Age is not the only thing that makes a building historical. The traditional materials and craftsmanship in the original construction of your historical building are an essential part of its historical fabric. Preserving its architectural integrity can only be done by using the same traditional materials and craftsmanship that made your building what it is today – a picture of the past. Original or historically-accurate siding on a historic home or building is an overt example of a building’s era and unique characteristics. 


Photo by Pierre Châtel-Innocenti on Unsplash

 

Synthetic vs. Wood Siding: Life-span

  • Synthetic siding has a potential life of at least 50-60 years
  • Wood siding has a potential life of at least 200+ years

Wood was abundant in Early America (and continued to be so throughout our history), and thousands of historical buildings in the Northeast are adorned with wood siding. Often, owners of these buildings look to alternative siding methods to replace wood siding deteriorated beyond repair. Their rationale for such practices is that they want to reduce the cost and effort of its maintenance, or to save on energy costs; conventional building wisdom maintains that vinyl and other synthetic siding lasts longer, requires less maintenance, and wastes less energy. The truth is this: in almost every instance, installation of synthetic siding will not save energy and maintenance costs. It will last a very long time; there are buildings that still retain their original synthetic siding applications from when they first appeared 50-to-60 years ago. And while that sounds significantly durable, it rather pales in comparison to the fact that there are historical buildings from 200+ years ago that still retain their original wood siding (siding that doesn’t sit many, many years in landfills when it needs to be removed). Synthetic siding won’t only add to landfills, it will also compromise the building’s historical integrity, and can cause irreversible damage to the building. 

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Synthetic vs. Wood Siding: Energy efficiency

  • Since walls are not a significant source of energy loss, synthetic siding proves, at best, a nominal energy savings

The myth that synthetic siding is more energy efficient than wood siding is pervasive and persistent – perhaps because it is easy to fall into the habit of assuming newer is always better. Newer is not always better, and even newer-with-an-insulated-backing is only nominally, if at all, better. The National Park Service’s Preservation Brief No. 3 highlights the fallacy regarding the weight placed on siding for energy efficiency, noting that walls aren’t even where the most heating and cooling energy is lost in historical buildings – the roofing system is. Spending money to replace wood siding with synthetic siding will not usually return the investment in energy savings for this reason. A much more cost-effective focus for energy savings are the windows, doors, and roofs of historical buildings.

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Synthetic vs. Wood Siding: Maintenance

  • Synthetic siding materials require much maintenance and can even create additional maintenance for other parts of the building

Synthetic siding materials are not maintenance-free. Aluminum will dent, and if painted, requires the same amount of paint maintenance as wood siding. To properly maintain and preserve aluminum siding, it must be cleaned regularly. Vinyl is a plastic and vinyl siding is subject to the same pitfalls as any other plastic: it cracks and shatters if impacted, it deteriorates with exposure to the extreme temperature changes of summer-to-winter and back again, and it simply cannot be installed to maintain a tight fit in both summer and winter because of the amount of expansion and contraction those extreme temperature changes cause. Vinyl siding will even interfere with a building’s ability to “breathe” and result in excess moisture retention and airflow problems causing unhealthy air quality for the building’s occupants, actually creating additional maintenance needs for other materials, systems and areas of the building.

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Synthetic vs. Wood Siding: Historical integrity

  • Synthetic siding does not preserve the many features of wood siding applications that contribute to the very fabric of a building that makes it historical

Synthetic siding will compromise the building’s historical integrity. The National Park Service’s Preservation Brief No. 8 explains that the materials of a historical building contribute to its historical fabric, noting that “Preservation of a building or district and its historical character is based on the assumption that the retention of historical materials and features and their craftsmanship are of primary importance.” There are many features that make wood siding of primary historical importance to your building. The tools used, geographically-specific craftsmanship techniques, types of clapboards and how they are manufactured and installed, the profiles, decorative edging, and patterns of application that make historical wood siding worthy of preservation are all lost when synthetic siding is used. For example, wood siding on Mid-Atlantic buildings from the early 1800’s to the early 1900’s had distinctly different looks, features, and craftsmanship techniques than those in New England during the same time frame. The stock synthetic siding options available today simply cannot achieve that same level of variation between historically significant architecture styles. 

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Synthetic vs. Wood Siding: Serious health problems

  • Synthetic siding not only masks the health of a historical building, it deteriorates it, endangering both the building and the people who live or work in it

Synthetic siding causes more serious problems. Wood siding on a historical building is also one of the most easily read indicators of the general health of the building. Paint peeling from wood siding can be an early warning signal that there are moisture problems threatening the building, and can sometimes even indicate where those problems are rooted (e.g., gutters or downspouts that aren’t working, improper flashing/weatherproofing, etc.). If wood siding is replaced by or covered with synthetic siding, it often masks any early signs or symptoms of moisture issues and results in more extensive moisture damage. Not only does synthetic siding mask the health of a building, it deteriorates that health. Since synthetic sidings to not allow a house to breathe the way wood siding does, it exacerbates any moisture problems that are present or develop in the future by essentially locking the moisture in the building. In doing so, synthetic siding encourages the growth of molds that turn the building’s air quality into a toxic environment that endangers the health of its occupants. Vinyl siding specifically also carries other health and safety concerns like the toxic fumes it emits when heated, and the cancer risks currently thought to be connected to the polyvinyl chloride plastic resin vinyl siding is made out of. 

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Synthetic vs. Wood Siding: Damage

  • Synthetic siding can result in permanent damage to the character-defining features of a historical building

Synthetic siding can cause irreversible damage to the building. An uneducated, and often heard argument claims that when need be, vinyl siding can simply be removed if it is applied over top of the original wooden siding. This is in part true, but it is in part reflective of a naïve understanding of what contributes to the historical fabric of a building, and how even seemingly simple changes can result in permanent damage to that fabric. Once again, Preservation Brief No. 8 from the National Park Service sets the record straight. It states, “there is frequently irreversible damage to historic building materials if decorative features or trim are permitted to be cut down or destroyed, or removed by applicators and discarded.” During the installation process of synthetic siding, even if it is only being applied over existing wood siding, the original wood siding can be permanently damaged by furring strips nailed onto the walls to create a flat surface to install the new siding on. Windows, door trim, cornice, decorative trim and molding, and other projecting details are sometimes permanently altered because the cost of custom-fitting the new synthetic siding to retain their character is too much.

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Evaluate your building’s siding:

  • Do any areas of my historical building have synthetic siding materials applied over wood siding?
  • If yes, do I have a plan for restoring the original wood siding?
  • Are there areas of my wood siding that have already been replaced because of deterioration?
  • Were they replaced with comparable wood materials and craftsmanship features?
  • Do they blend in with the original siding?
  • Is my wood siding evaluated regularly and properly maintained? Is it re-painted every 5-10 years?
  • Do I have a maintenance plan and agreement with a qualified and competent historical restoration company to ensure proper maintenance of my wood siding?

 

FALL MAINTENANCE FOR YOUR HISTORIC HOME Fall is here. This brings Halloween fun, Thanksgiving, fall abundance, and cooler weather. It also signals the transition to winter and harsh conditions for our homes. We have often repeated, maintenance is essential for a home, especially an old or historical one. Read on for your fall maintenance checklist. 

Autumn Leaves. Photo by Greg Shield on Unsplash.

 

Take a walk around your property and determine what needs to be addressed. Here’s a list of common fall maintenance tips to get you started:

  1. Make exterior repairs. 
    • Look for general damage to your roof, siding, and foundation – schedule repairs before winter
  2. Inspect your roof. If you have a steep roof or a multistory house, avoid injury by using binoculars to inspect your roof. Common signs of damage to your roof include:
    • Buckling, cracking, missing shingles – these should be replaced immediately
    • Rust spots on flashing – remove rust, and if metal is worn through, paint with metal primer and metal paint 
    • Large amounts of moss or lichen – this likely indicates your roof is decaying underneath, so call a pro roofer to evaluate ($100-$200). You can also prevent this decay by laying a wood shingle roof on lathe rather than sheathing (modern approach) as air can circulate and dry out the wood 
    • Cracked or loose boot(s) (rubber collars that fit around plumbing vent stacks) – call a pro roofer to evaluate (they will charge $150-$300 to replace a boot)
  3. Schedule chimney cleaning and fireplace/heating system maintenance. 
    • Blockages in the chimney – cleaning the chimney (and furnace and boiler) are important safety precautions before turning on your heat
    • Missing chimney cap – add one to prevent wildlife crawling down the chimney. You can find custom chimney caps at certain companies for non-standard sized chimneys
    • Damper not working – look up into fireplace flue if the damper is not opening and closing, to see if there is an obstruction (you should be able to see daylight at the top of your chimney)
    • Clean creosote buildup from your flue every other year – a professional chimney sweep will charge $300-$500
    • Missing or cracked bricks in firebox – request a professional fireplace and chimney inspection if you see any damage (professional inspections run between $160-$500)
  4. Clean your gutters and downspouts. If you are not comfortable using a ladder, be sure to hire someone who can help with this important task. 
    • Clogged gutters may allow water to pool which can damage your roof or siding – remove leaves and debris 
    • Flush gutters with water, inspect joints, and tighten brackets if necessary
  5. Direct water drainage away from your foundation. 
    • Soil that is too flat near the foundation of the home may soak and cause leaks or cracks – make sure soil slopes away from the house at least 6 vertical inches over 10 feet to prevent this
  6. Check the foundation and entire exterior for cracks and gaps. Both animals and natural weather forces can enter and destroy your home. Loss of heat can also increase your heating costs.
    • Cracks or unsealed areas – caulk around areas where masonry meets siding, pipes or wires enter the house, and around windows and doorframes. Do NOT use small cans of spray foam at wood contact areas – it will cause rot
  7. Conduct an energy audit. 
    • DIY – instructions can be found at energy.gov
    • Professional – trained auditors can assess your current energy efficiency and provide a list of recommended improvements like upgrading to Energy Start appliances, adding insulation to your attic or adding more weather-stripping ***The caveat is you should pay for their service – otherwise their “solution” will be what they are selling, including replacement doors and windows which we do not generally advocate for older homes. Also make sure they are familiar with historic buildings and their unique concerns
  8. Increase warmth in your house. 
    • After you’ve installed storm windows and doors (and removed all screens) adding weather-stripping around windows and doorframes can not only keep your house warmer during the winter months, but also cut energy costs
    • Drafty doors – place door sweeps at the base to keep the cold out and the heat in
  9. Shut off exterior faucets and store hoses inside. 
    • Shutting these off can protect pipes from freezing
    • Drain hoses before storing indoors
  10. Check walkways, railings, stairs, and driveways for winter safety. 
    1. Loose, slippery, or uneven surfaces – make sure to tighten loose railings, correct uneven walkways, and free drains of debris
  11. Check safety devices. 
    • Test smoke and carbon monoxide detectors – replace dead batteries
    • Check the home for radon (you can find radon monitors here) – with cooler weather, windows are shut more and radon can become trapped inside the home – hire a professional to address radon issues  
    • Check expiration dates on all fire extinguishers – replace if expired 

 

For further resources and reading:

  • Read our previous post – here – on the importance of maintaining a historical home
  • Read our previous post – here – on how maintenance IS preservation, and find a myriad of additional resources related to home maintenance in that post
  • Sign up for our free Maintenance IS Preservation Report here

A few months ago I came across an article from DWM Magazine (DWM = Door and Window Market) about a lawsuit filed on Oklahoma against Pella Corp by a homeowner that alleged the Architect Series windows have design and manufacturing defects as result they are leaking and causing premature wood rot and damage.  You can read the article here: https://www.dwmmag.com/lawsuit-alleges-pella-architect-series-windows-were-defective/

Replacement windows come in a wide range of options and price points – unfortunately paying more doesn’t always equal greater quality when choosing a replacement window (and if you have your original windows they most likely can be repaired and as energy efficient as replacement windows – science backs this.)  You can read more here:  https://practicalpreservationservices.com/put-replacement-windows-to-shame-what-that-nice-salesperson-doesnt-want-you-to-know/

Reading the article about the lawsuit against Pella I wasn’t surprised by the issue the homeowner had.  They had purchased aluminum clad (wood wrapped in aluminum) ‘designed and manufactured to protect the wood’ and I’m sure they also tout the maintenance free aspect of the design.  The complaint alleges, “[An] investigation revealed that the defendant’s Architect Series windows aluminum exterior cladding had design and manufacturing defects allowing rain water to drip in to the interior wood and that the rain water dripping in to the interior wood over the years resulted in rotted wood  internal destruction of the windows.”  This is a common issue when wrapping wood (I won’t even get into the fact that the pine they are using is inferior to old growth wood) and is one of the reasons the Secretary of the Interior advocates for NOT wrapping wood in metal or synthetic siding: https://www.nps.gov/tps/how-to-preserve/briefs/8-aluminum-vinyl-siding.htm

“Since aluminum and vinyl sidings are typically marketed as home improvement items, they are frequently applied to buildings in need of maintenance and repair. This can result in concealing problems which are the early warning signs of deterioration. Minor uncorrected problems can progress to the point where expensive, major repairs to the structure become necessary.

If there is a hidden source of water entry within the wall or leakage from the roof, the installation of any new siding will not solve problems of deterioration and rotting that are occurring within the wall. If deferred maintenance has allowed water to enter the wall through deteriorated gutters and downspouts, for example, the cosmetic surface application of siding will not arrest these problems. In fact, if the gutters and downspouts are not repaired, such problems may become exaggerated because water may be channeled behind the siding. In addition to drastically reducing the efficiency of most types of wall insulation, such excessive moisture levels within the wall can contribute to problems with interior finishes such as paints or wallpaper, causing peeling, blistering or staining of the finishes.”

Trapping the water behind the metal and against the wood is the same issue that is being alleged as a design fault in the Pella lawsuit.  The lawsuit also alleges that the company had known this was a design defect since 2006 (there had been previous class action litigation).  The complaint sums this up, “[Pella] breached its duty to disclose to plaintiff that its Architect Series windows had a substantial risk of leaking because of design and manufacturing defects and that the leakage would result in rotted wood and that after the purchase of the windows defendant breached its duty to inform plaintiff that defendant’s Architect Series windows had a very high likelihood of leaking that would result in rotted wood”.

As I stated previously I wasn’t surprised by the cladding causing wood rot and I do think a window manufacturer should understand this and design to avoid the condition, but most people move every 7 years and if the previous homeowner paid the expense of replacement windows when the windows begin to fail it is a ‘necessary’ cost of maintaining a home and the replacement cycle continues.

 

Videos

Title: Designing a Sympathetic Addition to a Historic Home

Danielle Keperling talks about the importance of making sure your work is never something that can not be undone. Important tips included such as make sure your new addition is compatible and differentiated from the historical building, and best locations in a home to build sympathetic additions.

Title: Existing Building Code Impact on Current Projects

Danielle Keperling talks about Pennsylvania’s existing Building Code and Universal Building Code that was adopted in mid 2000’s. Existing building code is not often known by contractors and home owners, but it allows some variation and gives exemptions from modern code as long as the use of the building is not changed.

Title: Energy Efficiency of Older Homes vs. Newer Homes

Danielle Keperling talks about the energy efficiency between older and newer homes. If homes were built before 1950, the older homes are still as energy efficient as newer homes. The Federal Government has conducted studies of homes built between 1950 and 1970 and found they are the biggest energy users. You can improve energy efficiency by having an energy audit done by a historically sensitive energy auditor.

Title: Hiring The Right Contractor

Danielle Keperling talks about the importance and how to find the right contractor. Look for someone who specializes in historic homes. Any contractor should have license and registration, but for an historic contractor, check references and look at their portfolio work, compare size, and have a good relationship with them.

Title: How Do I Maintain My Older Home

Danielle Keperling talks about how to maintain an older home such as evaluation of all the systems of the home that can fail and then see what can be done by most pressing to aesthetic by preparing a semi-annually/annually maintenance plan. “Older homes” are considered homes built before WWII (mid 1940’s).

Title: Planning a Historical Building Project

Danielle Keperling talks about the best way to approach a historic building project such as creating a plan focused on your needs, know how space is being used, and create a wish list focused on the historic nature of the building. Next is project development which includes interviewing contractors, getting prints, investigating building codes, and having a budget.

Title: Advantages Of Using Lime Base Mortar

Danielle Keperling talks about the advantages of using Lime Based Mortar over Modern Portland Cement preventing irreversible damage to brick allowing water to escape during the freeze/thaw cycle.

Title: Maintaining My Non-Historic Older Home

Danielle Keperling talks about the stewardship of homes and preserving buildings such as removing extinct components, even though they are not officially historic and keeping historic fabric intact.

Title:Choosing Replacement Parts

Danielle Keperling talks about choosing replacement parts such as documenting deteriorating or missing pieces and replacement in kind (replacing with the same type of material, same/similar methods, same color, and same consistency.)

Title: Installing Synthetic Materials

Danielle Keperling talks about using synthetic materials for structural reinforcement (kept in a non-heavily trafficked area and non-visible.) When selecting a substitute material, make sure it has a proven track record and will not damage the historic fabric of the building.

Title: Vinyl Siding

Danielle Keperling talks about the damage of synthetic siding such as moisture causing deterioration that is unseen and the damage done during the installation process.

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Preservation and sustainability. What does one have to do with the other? If we examine these terms more closely, we can see that older buildings are inherently “green” or sustainable because of “embodied energy” (all of the energy used to build the building that would need to be expended to build something else). In fact, the report from the National Trust for Historic Preservation “The greenest building” states:

“This study finds that it takes 10 to 80 years for a new building that is 30 percent more efficient than an average-performing existing building to overcome, through efficient operations, the negative climate change impacts related to the construction process.”

This statement about life cycle analysis indicates that the construction process is resource intensive (both in production and transportation of new materials and landfill debris – about 20%-25% of landfill waste is construction-related). Reusing an existing building is the ultimate recycling, so preservation and sustainability are often inextricably linked, and this link highlights the importance and value for sustainability inherent in preservation.  


Photo by Random Institute on Unsplash

 

PRESERVATION’S LINK TO SUSTAINABILITY

Not surprisingly, both the preservation and the “green”/sustainable initiatives have significant common ground and can work in concert with one another. This is particularly relevant in light of concerns regarding climate change and major environmental concerns. The National Trust for Historic Preservation formed the Preservation Green Lab in 2009 to strengthen the connection between preservation and sustainability, and updated the name to The Research and Policy Lab in recognition of expanded needs. The National Trust for Historic Preservation has increased focus on climate change impacts on our heritage. There is also an International Climate Heritage Network to address the intersection of climate change and other environmental disasters on arts, culture, and heritage.

However, at times in the recent past, green and preservation agendas have been at odds and there has been a bias in the sustainable building field to start over with new buildings and materials, as pointed out by Tristan Roberts, and The Washington State Department of Archaeology and Historical Preservation’s (DAHP) Sustainability and Historic Preservation Executive Summary from 2011. The Whole Building Design Guide’s Historic Preservation Subcommittee (WBDG) notes that there has also been a stigma attached to preservation and it has been (often inaccurately) labeled as inefficient and requiring overwhelming or costly procedures to retrofit energy efficient systems into old systems. Additionally, Roberts reports that certain sustainable products that are made of recycled content or other sustainable materials may not be approved by the National Park Service’s Secretary of Interior’s Standards for Rehabilitation simply because they disrupt a building’s character-defining appearance. However, preservation and sustainability are far from being mutually exclusive. As Roberts reports:

“Both the environment and cultural heritage suffer when buildings are treated as disposable.”

Below, we outline characteristics of preservation that lend themselves to sustainability:

  • Energy Efficiency. As noted earlier, it also takes less energy to maintain or rehabilitate an existing building than to demolish an existing building to construct a new building, even if that new building is “green.” Restoration involves less carbon emissions than new construction. Comparatively, DAHP noted in 2011 that new buildings accounted for 40% of all extracted energy sources and 68% of all consumed energy per year. DAHP also cited the U.S. Department of Energy (DOE) who shared data indicating that “commercial buildings constructed before 1920 actually use less energy per square foot than buildings from any other decade up until 2000.” New buildings made of new materials means one must consume energy to both create and ship those materials, and this also contributes to carbon emissions. DAHP adds that many historical buildings were designed with “passive systems,” or systems that took advantage of things like natural light, ventilation, and solar orientation when electrically-powered options did not exist. These passive system characteristics are all inherently sustainable and meet the same “green” goals of the sustainability camp. You can read more of our articles on energy efficiency in our archives here

 

  • Durability and Waste. Preserving a historical building reduces consumption of materials, and retaining old material creates less construction landfill waste. Green buildings should have materials that are both durable and repairable, whether that green building is new or old. Many new green building products are durable, but not necessarily repairable (read our repair archives here). Additionally, to build a new building with new materials, you have to create and ship the resources (both of which take energy), and often they are placed on newly cleared land which takes energy but also may be removing resources such as forest or farmland. Rehabilitating an existing or historical building eliminates a lot of these issues. Even reusing durable, salvaged materials from buildings that are torn down keeps those materials out of landfills and provides green materials for another building. However, more wasteful decisions are perpetuated, as Roberts points out that the construction industry often falls prey to “short-term thinking,” focusing on what works in-the-moment and disregarding long-term outcomes. Despite these benefits of preserving or rehabilitating older buildings, there can be challenges related to durability and waste in older buildings. Roberts notes that not all older buildings were well-built with durable material or construction, so in some cases, building damage is not due to neglect or abuse, but the way the building was constructed (e.g., some buildings with structural steel that is corroded cost a lot to repair). Further, as more modern buildings age and qualify as “historic” each year, these sometimes less durably-built structures pose new challenges for both the preservation and sustainability movements.

 

“GREENING” YOUR HISTORICAL COMMUNITY, BUILDING, OR HOME

Several efforts at the international and national level have been highlighted here for increasing connections between preservation and sustainability. WBDG’s Historic Preservation Subcommittee adds several guidelines that marry LEED guidelines for “greening” existing buildings with processes that incorporate specialization for historical buildings (here). However, there are several things individuals in and building and homeowners can do as well. On a community scale, The National Trust for Historic Preservation includes information on helping preserve your community and designating a historic place. Below are tips for owners of older buildings and homes. These are based primarily on the framework provided by the National Trust for Historic Preservation’s Meghan White in “8 Ways to Green Your Historic House“, listed below, as well as information from other articles and our own expertise:

  1. Conduct an energy audit. Know where energy may be leaking. White states “A popular example is the blower door test. This test involves using a high-powered fan to take the air out of the building, which depressurizes the interior. The difference in air pressure is then measured with an air pressure gauge.” The pressure difference allows outside air to come into the building via openings, which reveals areas you’ll need to seal.  
  2. Don’t replace windows (or doors, or siding, etc.). As we’ve noted several times, a big misconception is that historical windows are to blame for the drafts in homes. White reports “As the National Trust’s Research & Policy Lab (formerly known as the Preservation Green Lab) notes in their study Saving Windows, Saving Money, historic windows rarely deserve to be completely replaced. Instead, weatherstrip them or install minimally invasive storm windows so that they keep the drafts out and lower your energy bills. The study found that retrofitting windows are the most cost-efficient way to decrease a historic house’s carbon footprint. As a bonus, old growth wood found in historic windows lasts longer than modern day wood, so preserving your historic windows will keep you from having to replace them more often.” Similar points can be made for doors, siding, and many exterior home parts that separate the outside from the inside. DAHP adds that more energy is lost from plumbing openings and uninsulated ducts than windows. The key is to repair, restore, and maintain these protections from the outside elements.
  3. Insulate the attic and basement. White notes that energy escapes through uninsulated spots such as basements, crawl spaces, and attics. Insulating them can help to prevent air from escaping. They say “Cellulose is a great option because, unlike spray foam, it’s reversible.” They also caution “You should refrain from insulating walls because you’re removing the permeable vapor barrier inherent in historic structures. The walls of historic houses are made to breathe, but inhibiting movement of air and heat through and around the wall can lead to issues like trapped moisture.” This issue is closely related to our points about differences in modern mortar and historical mortar, and the inherent breathability of old wall materials. 
  4. Take advantage of your house’s natural passive heating and cooling. White says “Artificial cooling and heating methods can be some of the highest energy consumers in a historic house.” They suggest using your historical home’s shutters to cool your house naturally: open your windows and latch the shutters to allow natural air flow. The added bonus is it will shade your interior from the sun. Window awnings that are historically appropriate can also provide similar benefits. In cases where you want or need additional electric components, consider finding a preservation and sustainability-minded HVAC professional who can retrofit systems with little disturbance to your home’s historic fabric, as we discussed here
  5. Consider installing renewable energy sources. Installing solar, wind, or geothermal renewable energy sources on your historic property are also options to consider. White says “Solar panels produce electricity naturally and will help lower your bills. When connected to a utility power grid, modern wind turbines can also help create electricity using renewable resources and in a more cost-efficient manner. Read more about installing solar panels on historic properties here.” Tesla has also developed solar panels that are extremely sympathetic to the historical aesthetics of an older home, though it may be cost-prohibitive for many.
  6. Pay attention to your landscaping. Trees may help to conserve energy in your house,with deciduous trees providing shade in the summer and fallen leaves allowing sunlight to warm your house in late fall and winter. Another issue we acknowledge is environmental damage due to combined sewer systems in many cities. When it rains too much the system becomes overwhelmed and this causes untreated sewage to be dumped into streams and rivers and contaminates waterways. The EPA fines communities every time this happens. As an individual homeowner, you can prevent some of your own contribution to this problem by: creating a rain garden to divert the water away from the storm drain and also away from the foundation; installing permeable pavers laid in the traditional manner (with sand underneath instead of mortar); and you can build a drywell. Check with your local municipality to see if they have a grant to help defray the costs of to property owners who make these changes. 
  7. Change your Lightbulbs. White points out “According to the General Services Administration, High Efficiency Incandescent (HEI) lamps reduce energy by 50 to 75% and use only 25% of the energy that regular incandescent bulbs use. They also don’t alter the appearance of historic light fixtures where the bulbs are visible, like LEDs do. Otherwise, LEDs are a good option when the bulb is obscured by opaque shades or lenses.”
  8. Reuse old materials or salvage. White encourages readers renovating historical buildings to replace missing pieces with materials from salvage companies before resorting to all-new material. This helps preserve historical pieces and prevents some landfill waste. 
     

IN SUMMARY:

Preservation and sustainability have much in common, and destroying or demolishing old buildings is more wasteful than helpful, even when replacing it with a new “green building.” It is best to preserve what we do have, by repairing, restoring, and maintaining these buildings. 

A façade. What is it? Most of us know that its most basic definition is “face.” In the case of architecture, this refers to the exterior side of the building, usually the front. Façades on buildings are often the first defining features we see. As times change, so do architectural design styles, and this is reflected in façades on old and new buildings. Façades can provide varying amounts of information about the building’s past and current functioning, or they can simply be really nice to look at. Regardless, they are often the one aspect of architecture that almost anyone has access to simply by being in front of us. Read on to learn why historical façades are more than aesthetics.


Exterior shot of the Kosciuszko House, from our archives.

 

IMPORTANCE OF FACADES

You may be thinking to yourself: Why is a façade important? Isn’t it just for aesthetic-purposes? The answer is: Yes, it is partially focused on aesthetics. And one person’s visually-pleasing cup-of-tea is not someone else’s, so not every façade is attractive to every eye. However, a façade serves many more purposes and provides many other benefits than simply fulfilling an aesthetic goal.

  • Historical Streetscape and Cultural Landscape. The front façade of your home is an important focal point not only for curb appeal, but for the entire community. The rhythm of the entire streetscape is set by the street-facing façade. A well-preserved façade helps to maintain the historic fabric and cultural landscape of the building and the area around it, further contributing to the identity of its environment and community. The National Trust for Historic Preservation and Mainstreet America provide further information on the impetus to save and preserve façades in keeping with these community and cultural concepts.

 

  • Visual Historical Records. Even things that were considered merely decorative at the time of their construction may currently serve a function as a visual replacement for a historic plaque, by virtue of their historically-defining characteristics. Essentially, period-appropriate façades that are preserved are visual clues to the time period of the building, enabling us to visually “read” some aspects of a building’s history.  We can discern the time period of the building based on the style, as well as time periods of later additions. Style also indicates the socioeconomic status of the builder/original owner.

 

  • Form and Function. A preserved or period-appropriate façade also may include functional aspects. Although the nature of design has clearly evolved, we know that form and function often go hand-in-hand in older buildings and this often rings true even on a façade. The ingenious marriage of form and function in their designs often lend to the “charm” that modern people associate with them, and that is typically missing from newer buildings. For instance, historical shutters most-definitely served a function as much as they added to the decoration of a home. Their functions included protecting occupants from prying eyes or intrusion,  weather protection, as well as UV protection of items inside the home, including wooden furniture. They might also provide a breeze to come through without having the window gaping open, and in some cases were substitutes for glass windows. Porches also served dual functions, providing a grand decorative entrance to the home, while also allowing for outdoor socialization (as well as alternative sleeping accommodations in the case of sleeping porches). Other façade design elements can also be functional in many ways. 

 

ISSUES AND CONTROVERSIES

Contractors, building owners, city planning committees, and the public do not always agree on how façades or their buildings should be built, preserved, or maintained, leading to a variety of outcomes and controversies.

  • Façade lost or destroyed. In some cases, an old home or building’s façade is modified, rendering it unrecognizable from its original configuration, and important historical elements are forgotten or lost. Some of the aspects most-threatened by these facelifts include original windows and doors, due to homeowners’ concerns about energy efficiency, cost, and maintenance, and the highly-advertised “maintenance-free” trap

 

  • Façade preserved but interior lost or destroyed. In other cases and as is more common, the façade is preserved while the interior is not. The Secretary of the Interiors’ guidelines for Historic Preservation focuses on the preservation of exterior features (the façade) by allowing historic commissions/HARB districts to regulate changes to buildings within the designated districts to what is visible from the public street (“streetscape” is the term that is used).  The interior is not regulated even in historic districts – leading to gutting of interiors while the exteriors are preserved.  I think this is because the historic preservation policy is based off of community preservation (“rhythms and patterns” is the term that is used) balanced with property owners’ rights – which is still a tension in regulated neighborhoods.  Easements are the only preservation tool that can preserve the interior (if stipulated in the agreement). We will discuss more of this in an upcoming blog post on interiors.

 

  • Façadism. This term refers to an even more extreme example than the one above. Simply put, façadism is when the façade is preserved but the building behind is completely lost or destroyed, and replaced by a completely new building. This is often seen in the case of adaptive reuse. This obviously is a controversial topic in the field of preservation, and some believe it should not be associated with true historic preservation. Locally here in Lancaster, the preservation victory of preserving the Watt and Shand Department Store façade in downtown Lancaster for the Marriott Hotel and Convention Center has been controversial, but I’d rather see the façade preserved than lost.

 

  • Façade and interior restored or preserved. In some cases, façades and interiors are beautifully restored and saved. See this post on an example of one of our complete exterior and interior restorations from several years ago. Another unique local example is also part of the Marriott complex. The Montgomery house’s exterior was preserved as the convention center was built around and incorporated the home into it, and the interior of the house was renovated to meet modern needs, making this a more thorough example of restoration incorporated into adaptive reuse. 

 

FAÇADE PRESERVATION TIPS

There are several things you can do to preserve or restore your historical façade, and we’ve included a breakdown of each of the most common elements of your home’s façade, as well as comprehensive information on overall maintenance and aesthetic/architectural style elements.

  • Entrances (porches and doors). The entrance to a home is one of the most attention-grabbing aspects of a façade. Visit our previous post on porches and doors for more information on restoring or updating your entrance. You can also visit our porch archives.

 

  • Windows and Shutters. Windows are another key component of a façade, and we’ve discussed many times the importance of maintenance or restoration of old windows vs. falling for the “maintenance-free” new window trap that is heavily touted by modern manufacturing companies and many contractors. Visit the National Park Service’s (NPS) site on windows, and NPS’s National Center for Preservation Technology and Training’s website on windows, and our window archives for more information on approaching your historical windows.

 

  • Siding and Paint. Siding can be just as vulnerable as windows are to replacement with inappropriate modern materials. Paint poses its own challenges in terms of safety (lead in old paint) but also benefits of historically-accurate (minus the lead) paints and paint colors. Visit NPS’s briefs on exterior paint issues and substitute materials, as well as our articles on siding and painting your historical home

 

  • Roofs and Chimneys. Roofs and chimneys can be essential elements of a home’s design and are distinctively different across architectural styles. Visit the NPS’s preservation briefs on roofing and mortar, as well as The Trust for Architectural Easement’s piece on historic masonry chimneys. The Wisconsin Historical Society also has a piece on Preserving Original Roof Features of your Historic Building

 

  • Gutters. Although these utilitarian features are often overlooked when one thinks of more common aesthetic and functional features of a building’s façade, they are no less essential. The Trust for Architectural Easements discusses preservation of gutters and downspouts, and we’ve discussed gutters in our archives

 

  • Additions. Additions to homes, especially ones visible from the front of the home, are another important thing to consider when attempting to preserve most historical aspects of a façade. Visit NPS’s brief on exterior additions and Sheldon Richard Kostelecky’s article regarding sympathetic additions. 

 

  • Architectural character. Character is a major aspect of streetscapes and the cultural landscape, as well as period-appropriate architectural design style. Visit NPS’s brief on architectural character and our archives on architectural design.  

 

  • Overall maintenance. Visit our maintenance archives, including many recent and up-to-date articles on maintaining your home’s exterior. 

IN SUMMARY:

There’s more to a façade than meets the eye. If you would like help preserving or restoring your home’s  façade beyond the resources presented throughout this article, feel free to contact us to discuss your options. 

 

Well, it’s that time of year again. The weather is warming up a bit as we move into the Spring Season. In the 19th century, before vacuums came into common use, early spring was a time to open windows and sweep homes from “top to bottom” to herald the coming of warmer weather. Your spring maintenance projects can be handled the same way – from roof to foundation. Given that many of you are likely restricted to your homes during the crisis related to the Coronavirus, it might be helpful to think about maintenance as a means to manage boredom and anxiety until some normalcy returns. Afterall, maintenance is preservation for the long haul. Read on for our overview of the benefits of maintenance.

Photo from the National Park Service’s guidelines for maintenance of historic buildings.

 

WHY IS MAINTENANCE IMPORTANT?

I know you have heard us talk a lot about maintenance over the years if you have followed us for any period of time (certainly if you read our blog post on painting your home’s exterior from last week), but we cannot emphasize its importance enough, especially for owners of historical homes: MAINTENANCE IS PRESERVATION. To drive this point home, preservation is defined by the Secretary of the Interior’s standards as:

“to sustain the existing form, integrity, and materials of an historic property.”

Preservation is also the first step of “intervention” based on the Secretary of Interior’s standards and guidelines. Having a maintenance plan helps to preserve the building, slows the natural deterioration cycle, and helps maintain a budget of planned projects rather than major emergency projects (that can cause hasty decisions to be made that may permanently damage the structure).

 

INITIATE YOUR MAINTENANCE PLAN

You can begin to develop your maintenance plan and schedule by following the checklists in the National Park Service’s Preservation Brief No. 47 “Maintaining the Exterior of Small and Medium Size Historic Buildings.” The goal of the checklist is to ensure that the structure is sound and that water is kept out of the building. Having a regular routine looking at the exterior of the building – during a light rain or after a freeze – can help to determine where the water is coming in and can highlight problems that might otherwise go unnoticed.

 

REPAIR vs. REPLACEMENT

Once the maintenance plan is made, the decision to repair building components that have begun to deteriorate is an important preservation decision. Repairing rather than replacing helps to retain more of the historic fabric of the building (an important preservation goal). As we’ve noted in the past, and as the Secretary of the Interior’s Guidelines for Rehabilitation recommends, replacement in kind  is preferable. Replacement in kind means to replace with materials that are the same as what you are replacing: wood for wood, stone for stone, etc. There is a little bit of wiggle room for “compatible substitute material,” such as epoxy. We choose replacement over repair in cases where 50% or more of something is deteriorated, based on guidelines. However, this is a judgment call as there is no hard or fast rule for this. Usually someone who does not work on older buildings or someone that has a replacement mindset will set this bar much lower. Another factor in replacement in kind is the material selection. For example, old-growth wood is much more rot resistant and durable than the second-growth wood available now. We typically use a tropical hardwood or salvaged wood (from an architectural salvage dealer) to ensure that the replacement wood is going to be durable. Make sure the wood components are solid wood, not finger jointed (finger jointing is the process of making smaller wood lengths into longer pieces – most trim and modern window and door frames are finger jointed). This allows water more access points into the wood. And, because modern finger-jointed wood is (usually) inferior second growth pine the deterioration process is accelerated. Ensure that all replacement wood is treated with a preservative (like BoraCare) and prime-coated with an oil-based primer on all sides. If you are using epoxy repair (which we do for smaller repairs and non-wood repairs such as metal and masonry) make sure you remove ALL rotten wood, use consolidant, and then the wood fill epoxy. Most epoxies can be sanded, molded (if necessary), and then finish painted.

 

THE “MAINTENANCE FREE” TRAP

Many of you have likely seen ads for maintenance free products for your home, promising you that you will gain a lot of time by installing their product on your building. Sadly, many maintenance free products are maintenance free because when it comes time to maintain them you just replace it for the new version of the product. This may save time, but it also keeps you stuck in the cycle of replacement: continually buying replacements to keep the product manufacturers in business. Meanwhile, traditional materials are “greener” and more cost-effective in the long run because they are repairable. Cost and eco-friendliness aside, there are other issues with maintenance free products in older buildings. The National Park service’s Preservation Brief No. 47 “Maintaining the Exteriors of Small and Medium Size Historic Buildings” offers the following cautionary notice for historical building owners:

“It is enticing to read about ‘maintenance free’ products and systems, particularly water-proof sealers, rubberized paints, and synthetic siding, but there is no such thing as maintenance free when it comes to caring for historic buildings. Some approaches that initially seem to reduce maintenance requirements may overtime actually accelerate deterioration.”

Often times, we will see water and moisture trapped behind these maintenance free products causing rot that is unseen until replacement is necessary.

 

FURTHER RESOURCES:

  • Links to our Facebook live video series from last year regarding maintenance of your historical home.

 

  • Link to our Podcast from last year with more answers to older home maintenance questions posed by our listeners. The podcast included discussion of water infiltration through masonry walls, paint-related questions, as well as wood repair and preservation.

Winter may soon be coming to a close, but there’s still time during the tempestuous month of March for Spring to “come in like a lion,” as the old proverb goes. The uncertainty of weather related to climate change aggravates the issues we already see at the end of Winter as well, adding to the concerns of homeowners attempting to maintain the energy efficiency and temperature of their homes. With that in mind, we’re focusing on energy efficiency for historic buildings for today’s blog post. 


Photo by Alessandro Bianchi on Unsplash

First, let’s debunk a myth about old homes and energy efficiency. A common misconception about older buildings is that they are drafty, inefficient energy hogs. The truth is that the buildings with the worst energy efficiency were built between 1940-1970. Energy was cheap and there wasn’t a big push to conserve our resources during that time-period. Buildings constructed before 1940 were made with energy savings, thermal performance, and physical comfort in mind. By maximizing natural sources of heating, lighting, and ventilation, these buildings were comfortable in all seasons.

Still concerned about energy efficiency in your historic building or home? Read on for advice on improvements that will not sacrifice the historical integrity of your space.
________________________________________________________________________

TIPS TO INCREASE ENERGY EFFICIENCY

ON YOUR OWN:

  • Change your Habits.  Install timers or motion detectors on lights, attach self-closing mechanisms on doors that might otherwise hang open, install fans and raise your thermostat temperature, use LEDs in your lights and turn off “vampire” devices that use electricity in standby mode or that use electricity in standby mode or whenever that are plugged into an outlet.
  • Remove focus from Siding. Remember our previous post on siding on historic homes. Walls themselves are not a significant source of energy loss, so replacing original siding with new synthetic siding really does not cut costs or improve energy efficiency.
  • Caulking or Weather-Stripping. The easiest tip for increasing the energy efficiency of your building is to reduce the air infiltration using caulking and/or weather-stripping. You can do a self-audit of the envelope of your building (roof; walls and wall penetrations including doors, windows; floor, and foundation) to determine if these methods are necessary. If there are places that you feel cold air coming in you can add additional weather-stripping or caulking to the area and seal the crack. In warmer months this will also stop your conditioned air from escaping to the outside.           2 points of caution:
    • Only use the spray foam against masonry penetrations – it will cause any wood it is against to rot
    • Do not make the building too tight – older buildings were built for air to move and if all air movement is stopped it will cause problems with moisture accumulation
  • Combat the Stack Effect. The method above is helpful, but it does not give you the highest return-on-investment for making your home energy efficient because of the Stack Effect. To combat the Stack Effect, insulate at the basement floor (where the air comes in) and at the attic (where the air goes out). It’s also important to determine the R-Value (measure of thermal resistance) for your area to ensure you are most effectively stopping air leaks.  You can find your recommended R-Value here.                                                                                                                                                                Options for insulation:
    • “Green” or environmentally-friendly options (natural materials like cellulose and wool)
    • Fiberglass
    • Spray foam
    • Foam board (purchases can be made at big-box stores or SIPS)

WITH PROFESSIONAL HELP:

  • Seek Professional Assistance. Review our post on hiring the best person for the job. 
  • Have a Maintenance Appraisal Performed.  If you are concerned about identifying air leaks on your own, a maintenance appraisal performed by a qualified contractor will locate any source of air leakage and provide you with a plan-of-attack to remedy the problem without damaging the historic aspects of your home.
  • Schedule an Energy Audit.  Both the maintenance appraisal and an energy audit are absolutely essential things that need to be done BEFORE you implement any energy improvement measures in a situation where you do not have enough knowledge to take care of things yourself.  The energy audit will evaluate your home’s current energy performance and identify any deficiencies in both the envelope of your home and/or mechanical systems.

FURTHER READING:

Window repair, restoration, or replacement is an unavoidable topic of concern in historic buildings. Windows in your historic property are like the eyes of the home. They are an important piece of the historical fabric of the location, and also play an integral part in energy efficiency of the property. Simultaneously, they are one of the most vulnerable and “at-risk” elements of our architectural heritage. Replacement is not always the most cost-effective or energy-efficient answer. Determining the extent of disrepair in your windows is your first step in deciding whether to repair, restore, or replace them. 

Photo of our restoration work on windows at Franklin Street Station in Reading. 

Why are original windows important? They are considered a significant feature of a building, making up both exterior and interior architectural elements and usually 20-to-30 percent of the surface area of the building. The shape and materials, moldings, trim and window pane arrangements are all clues to the age of the building. To further illustrate these unique characteristics, here are examples of window styles and characteristics from the 18th, 19th, and early 20th century. The majority of the features that make original windows special are not replicable in replacement windows; you could replicate them in reproduction windows, but that is not what most people think of when they are discussing replacement windows. These elements include antique (wavy) glass, true divided light sashes, and traditional joinery.

Why are original windows endangered and at-risk? Several preservation organizations, including Maine, Virginia, and New York, have noted in recent years the endangered status of historic original windows. Even we have had first-hand experience talking with well-intentioned homeowners who’ve been convinced by saavy sales people to replace their original windows with modern ones under the guise that they are more cost-effective or energy efficient, only to regret the decision a few years later when the “superior” new windows are no longer functioning properly and are incurring more costs for energy, repair, and replacement. 

Are original windows energy efficient and cost-effective? Energy efficiency is a major concern when it comes to windows. We’ve noted in a previous post on Siding on Historic Homes that heating and cooling energy loss is associated most with windows, doors, and roofs, and this is often worse with modern replacements and materials. Meanwhile, original windows have a proven track record of durability that far exceeds that of new replacement windows, as long as they are properly maintained. In fact, most are 100+ years old. The National Park Service’s Preservation Brief No. 3 and their Testing Energy Performance of Wood Windows in Cold Climates both discuss energy efficiency in greater depth. The latter of the two aforementioned resources points out that replacing historic windows does not necessarily result in greater energy savings than upgrading that same window. If you’re short on time, you may instead choose to read one of our other brief articles on energy-efficiency and cost-effectiveness of original windows. On average, the energy savings after a replacement window is installed is less than $2/year. Restoring and repairing original windows can achieve almost the same energy efficiency, and is more cost-effective in the long-run because new windows will not last as long. 

Now that you understand the significance of original windows and the importance of saving them, how do you know if your original windows are repairable or restorable? First, consider that most materials and methods used to build the original windows are made to be repairable, so there is a higher likelihood that they are salvageable. Replacement pieces can be made rather than replacing the entire unit (consider our woodwork at the formerly abandoned Franklin Street Station in Reading, PA, whose windows were in a shocking state when we first encountered them; alternatively, you can see the results in-person while enjoying craft beer and a bite to eat at Franklin Street Brew Pub now in the station). Things to evaluate to see what repairs windows might need:

  • Loose frames and sash components
  • Slipped sills
  • Poor fitting sash and storm assemblies, and misaligned frames
  • Loose, open, or decayed joints at sash or frame corners
  • Loose hardware, broken sash cords/chains, worn sash pulleys, locking difficulties
  • Deteriorated weather-stripping
  • Broken/cracked glass, loose or missing glazing putty
  • Peeling paint
  • Window well debris accumulation

Some of these issues are easy to see and address. Others, including locking difficulties and window well debris accumulation might signal a misaligned sash and could necessitate the involvement of a skilled person to make those adjustments (or at least consult with you about what to do). All of these repairs will increase the energy-efficiency of your windows.

What do I do if a previous owner already replaced the original windows and updated replacement is necessary? There are several options to choose from:

  • Rebuild with antique glass
  • Rebuild with true divided lite and insulated glass
  • Replacement with modern replacement windows – The National Park Service’s Preservation Brief No. 9 has a list of what to look for in replacement windows, as well as ideas of where to find historically sensitive replacement windows

For more information and resources:

  • Visit our window post archives link
  • We typically recommend 2 Canadian manufacturers for modern replacement windows: Norwood Windows or Loewen

When most people think about the post-World War II era of the 1950’s, among the things they think about are iconic TV shows like “Howdy Doody” and “The Ed Sullivan Show,” presidents Truman and Eisenhower, Rock-n-Roll, the emergence of teen culture, James Dean and Marilyn Monroe movies, and the Cold War. But historical preservationists equate the ’50’s with Mid-Century Modern architecture.

taylor-simpson-ljhszooqvTI-unsplash.jpgPhoto by Taylor Simpson on Unsplash

WHAT INFLUENCED MID-CENTURY MODERN DESIGN PHILOSOPHIES?

Escaping Nazi oppression, founders of the 1920’s Bauhaus movement, such as Mies van der Roche and Walter Gropius, brought their concepts of clean lines, angular compositions, and simple forms with them to America. The basic tenets of the Bauhaus movement blended with American architectural traditions, particularly Arts and Crafts and Frank Lloyd Wright’s Prairie School designs, and evolved into what is called Mid-Century Modern Architecture, which extends beyond the contraction of houses to furniture and interior design and is characterized by the use of modern materials, horizontal composition, large expanses of plate glass (including sliding glass doors), open floor plans, and are typically one-story residential buildings. Often there are changes in elevation within the home design that make it distinctly different from ranch-style homes, creating a fresh new architecture that didn’t harken back to the past. 

MID-CENTURY MODERN DEFINING CHARACTERISTICS

GENERAL PROPORTIONS
Classic modern houses are one story, spread out, and horizontal

ROOF TYPES 
Flat, sometimes slight single pitch, often asymmetrical

FENESTRATION
Floor to ceiling glass in living sections, horizontal strips in less public areas of the house

STRUCTURAL & FACEWORK MATERIALS
No character defining material … stone, brick, wood siding (both vertical and horizontal clapboard) were all used … possible decoration: larger chimney made of brick or stone

SPATIAL DESIGNATION & FLOOR PLAN 
Very open plans, usually with kitchen, dining area, and living room as one continuous space … carports are common with the roofline acting as an extension of the main horizontal roof … basements and attics are rare

CHIMNEY PLACEMENT
Substantial and made of stone … often appears at the peak of the roof

ENTRANCEWAY
Somewhat formal main entrance with decoration limited to a floor to ceiling glass sidelight … often enters directly into the kitchen or utility room from the carport

COLOR
White initially, with warmer and natural colors introduced later in the period

PRESERVATION CHALLENGES: MID-CENTURY MODERN ARCHITECTURE

Mid-Century Modern Architecture is characterized by its progressive designs and minimalist aesthetics that became popular in the post-World War II era, and contrast with their ranch-style counterparts, due to the fact that the designs make no reference to earlier building styles, like the Colonial Revival. The goal of Mid-Century Modern designers was to create a look that broke with the past, which often lent itself to outlandish details and futuristic elements that might appear more at home in science fiction. 

The way things were built, including houses, changed after WWII. There was a demand for new construction for returning GI’s who needed housing for their families. Prior to the war, during the Great Depression (1929-1939), there wasn’t much new construction outside of public works projects that were created as part of the New Deal, and in the early 1940’s all resources were devoted to the war effort. Due to the housing demand, a system was developed to create housing fast and economically, as expansion into the suburbs, a phenomenon that began in early 1900’s, continued.

GI’s not only needed housing, but also jobs, which increased the existing labor force. Materials were made to be installed by less skilled labor. Manufacturers began making building materials that were meant to be replaced rather than repaired, which created a workforce of product installers rather than skilled craftsman (a trend that continues today). 

The modern construction techniques allowed architects to experiment with forms and materials. Steel framing, first used in Chicago skyscrapers at the turn of the century, was used in Mid-Century Modern buildings, and enabled architects to create the walls of glass and open floor plans that characterize the style. Open floor plans were designed to promote more casual and integrated living spaces that could accommodate a variety of uses. Large expanses of glass framed by thin structural elements allowed for more contact with nature.

So, you own a Mid-Century Modern house, how can you tell if it’s considered an historic structure?
A building older than 50 years (or newer building if a historically significant event took place there), is eligible for the National Historic Register. Of course, there are other criteria, which you can find by visiting the “Eligibility” page at: 

https://www.nps.gov/subjects/nationalhistoriclandmarks/eligibility.htm

and the “How to Apply the National Register Criteria for Evaluation” page at:

https://www.nps.gov/subjects/nationalregister/upload/NRB-15_web508.pdf