Keeping it Real

I made the mistake of going Christmas shopping over the weekend and was forced to contend with the masses in the ritual of adorning the base of our tree with a bunch of stuff that nobody really needs. The experience made me think about the window industry. One outgrowth of our capitalistic society that I am disgusted with is the consumption-based mentality that has rapidly grown over the past fifty years. Manufacturers, advertisers, and the media have promulgated a lifestyle that is based upon fashion and instant gratification rather than substance. Just take a look at the hordes of people in the malls over the next couple of weeks if you don’t believe me. This boom of consumerism has given birth to a replacement society. When our cell phone breaks down, we replace it. When our television malfunctions, we swap it for a cheap replacement. Most of the clothing and furniture sold in the United States is cheap stuff manufactured in China that will need to be replaced before it goes out of style. And riding high on this trend for disposal is the window replacement industry.

Instead of pontificating about all the reasons one should restore historic windows rather than consider replacement, I'd like to address just one issue: replacement windows can ruin the look of a good building. Whether you are looking at vinyl, aluminum, wood, or steel replacement windows, there are very few manufacturers who offer acceptable facsimiles of the originals. These manufacturers contend with constraints that influence their engineering. Some are unable to replicate old windows because they use materials that cannot match the originals. Others are dedicated to sustaining a low price point and neglect to invest in suitable designs. And still others just don’t get it or don’t care to even pay attention. For the most part, the replacement window industry does a very poor job in offering products that look like the existing windows.

Even given vast improvements in UV inhibitors and advances in finishes, the vinyl window industry continues to produce primarily stark white products. Some manufacturers now offer a tan color. Talk about a segment that is mired in the Henry Ford era. They also contend with restrictions on size given the weak structural characteristics of the vinyl material and internal reinforcement. It is not uncommon to see two vinyl windows occupy an opening that once had a single double hung window simply because they cannot match the original window size. The vinyl window manufacturers are also under a great deal of pressure to maintain a competitive price point so most designs are very simplistic and ignore many of the profiles that add substance to the architecture.

The aluminum window manufacturers are very excited about the historic window arena given the state of the economy. They have become masters of attempting to make a standard window look custom. The formula they subscribe to is that you can make a standard window look like a replica by adding specially extruded trimmings to a basic window series. By applying a decorative brickmould and a surface-applied coped muntin bar to the window, it can now be promoted as “historic.” Most will even try to replicate the window lugs on the top sash by screwing a cast aluminum block to the lower corners of the upper sash. Unfortunately, the boxy appearance of the standard window design with stiles and rails that are much wider than the original completely alter the architecture. Many of these installations are set into an aluminum frame that is installed over the existing wood window frame, further infringing upon the sightlines of the original window.

The aluminum clad wood window manufacturers operate in a very similar fashion to their aluminum counterparts by taking standard products and adding trim such as brickmould and muntins that come close to matching existing designs. Stile and rail dimensions still fail to match. Their designs have size limitations on venting window units because of a an average sash thickness of only 1-3/8” and a cheap block and tackle balance system. This forces large units to become fixed or combined with other windows or infill. Most of the manufacturers have two options for replacement windows. One option is a package of two sash that are set in the original frame with a cheap plastic jamb liner that fails to match the existing finish. The other option is a window in a smaller frame that can be installed in the existing frame’s sash pocket just like a vinyl replacement window. The aluminum clad wood window manufacturers like to wrap the frame with aluminum break metal or profiled brickmould. This metal is often secured with exposed fasteners and caulking at all joints which attracts dust and fails within a couple of years. Often the break metal has a different finish than the window and fades at a different rate. Another disadvantage is a design that inhibits the ability to repair the window. If the glass breaks, the entire sash and often the entire unit must be replaced. So these manufacturers have successfully designed a bona fide “replacement window”.

So if you find yourself getting caught up in the spirit of consumerism this season and begin to have dreams of sugar plums and iPhones, remember that your work is your signature.  You really don't want to have your name associated with some of the common replacement window problems pictured below:

These stark white vinyl window replacements

had to be fixed windows since the window

opening is too big for a vinyl double hung.

 

 

 

And they even added decorative trim

to the infill for this aluminum window

replacement.  If you are going to ruin a 

building, you might as well do it with style. 

 

 

 

Note how these aluminum replacements

attempt to simulate a double hung

window with a fake horizontal rail.  I guess

if you are going to put an awning like

that over the entrance, it doesn't matter

what the windows look like.

Take a look at the aluminum window replacements on the

third floor compared to the original wood windows on

the second floor.  If this picture doesn't convince you of

how aluminum window replacements will change sightlines

than nothing will.

The reduced sightlines of an aluminum

replacement window don't look any

better from the interior.

This is a common situation where the

aluminum window manufacturer cannot

make a venting window of this size so

they settle on a fixed/hopper combo.

Look at the infill panels on these

aluminum replacement windows.

This aluminum clad wood window replacement shows how

the sightlines have been completely changed.  The aluminum

break metal has none of the profiles of the original millwork.

Also note how the window has faded at a different rate than

the break metal.

Note the exposed fasteners and dirty sealant

lines on this aluminum clad replacement window.

Observe the stark contrast in metal colors due

to using different finishes on the window and the frame.

Note the fake sash lug on the corner

of the upper sash.  Why even try to

match the original when it looks this bad? 

Architectural Felonies

I was looking at the construction documents for a county courthouse restoration project last week and was absolutely appalled at what the construction team was intending to do to this landmark property. Here is a building that was originally constructed in 1876 and is one of the most significant functioning courthouses in the State of Missouri. One would think that the restoration of such a building that is listed on the National Register of Historic Places would respect the integrity of the design and the existing materials. Instead, the request for proposals was asking for the original wood double hung windows that span 14 feet tall to be replaced. These monumental windows are the signature of the building. They are without a doubt a defining characteristic of the architecture. The architect for this project specified a complete replacement with a fixed aluminum system with small operable awnings. The replacement will look like a flat storefront system instead of a double hung window. How does this happen? How does a significant piece of architecture that is listed on the Register get butchered like this?

I am not a bleeding heart, tree hugging, fanatic who feels that every building must be saved and that nobody should make design changes to current architecture. I like to think of myself as a pragmatist who is capable of rationally evaluating the social and economic impacts of various preservation strategies. I am also sensitive to changes in design that might be required for repurposing a building. But there is a problem when compromises are made to significant architecture that defines a community. Although we are supposed to have checks and balances to prevent this from happening such as the National Park Service and the State Historic Preservation Officers, projects still fall between the cracks. So how does this happen? I think the following factors can contribute to what I would call an architectural felony.

1. Underfunded Budget

An underfunded budget is often responsible for compromises in the architectural details of a preservation project. It can initially be much less expensive to replace a historic wood window with a cheap vinyl unit than to restore the original. The low budget helps people ignore the fact that they are replacing a 100 year old window with a window that has a life expectancy of 20 years. I am constantly amazed at how lack of funds can inspire irrational behavior.

2. LEED Programs

Programs such as LEED promote a window replacement mentality for preservation projects. Since the USGBC is partially financed by building product manufactures, they encourage replacement with new materials rather than restoration. You can get points by replacing the windows with windows that have Energy Star Ratings, have a published U-Value under a certain amount, or utilize FSC lumber. Little consideration is given to options that enhance the energy performance of the existing windows. Also, this program ignores the costs of disposing of 100 year old windows with replacements that will last for only 20 years.

3. Anti-Terrorism Design

In the wake of the 1995 terrorist bombing of the AP Murrah Federal Building in Oklahoma City, the GSA adopted blast resistant standards for federal facilities. Since the window openings are vulnerable to blast exposure, the goal to upgrade the blast integrity of the fenestration often conflicts with the historic character of the windows. The design of blast resistant windows has no historic relevance and fails to match the existing systems. It is possible, however to make compromises where both agendas can be satisfied. Re-View has restored historic wood and steel windows and then installed a blast resistant storm window into the opening. We have also adapted existing windows with laminated glass.

4. Owner-Driven Preferences

Often the owners of the buildings and their maintenance departments get involved in the design phase of a preservation project and insert their agenda on the scope of work. This contingent usually is very focused on reducing maintenance costs and improving energy efficiency. There is a misperception that if one can replace the historic wood windows with aluminum or vinyl, you will never have to worry about painting again. Since this group has no formal preservation training, they tend to gravitate towards short-term solutions that have lower costs. These decision makers only hope that they will retire before the replacement windows have to be replaced.

5. Inexperienced Architects

There are a lot of very talented restoration architects in the United States. They achieved success by becoming students of the trade and learning on the job through the school of hard knocks. In these tough economic times, it is not uncommon to see architectural firms stretch beyond their competencies in the pursuit of other business opportunities. We often run into architects who have little to no experience on preservation projects. These newbies are inclined to utilize means and methods of new construction because that is their frame of reference. Inexpensive window replacements are a common specification item for inexperienced architects.

I guess I shouldn’t get upset about the windows on a single courthouse. Last year a tragedy occurred in Toledo, Ohio. The commissioners of the Seneca County Courthouse voted to demolish an architectural gem because it was less expensive to build a new courthouse. This signature building constructed in 1884 succumbed to the wrecking ball while protesters cried on the sidelines. One thing we could all learn from our friends in Europe is to show more respect for historic architecture. As preservationist we need to view ourselves as the stewards of the historic environment.

These magnificent double hung windows are
being replaced with aluminum storefront

Seneca County Courthouse Before Demolition

Seneca County Courthouse Demolition

Good Question!

Let's Not Get Too Testy

Testing in the fenestration industry has been practiced for many decades especially in the commercial sector. It has long been a common practice to conduct mockup tests on custom curtainwall designs that are project specific prior to fabrication and installation. These tests assure that the details as designed will perform as intended under the harsh realities of Mother Nature. The industry has also accepted testing of new window and door products to equip the consumer with an understanding of what they are actually purchasing. There is a big difference in structural, thermal, and air/water infiltration ratings for the hundreds of different window designs made from steel, aluminum, wood, vinyl, and fiberglass. Testing of these products enables one to determine the differences between various products. Architectural window testing has served the industry well in defining performance, influencing design, and establishing quality control. It is only natural, therefore, to be tempted to apply standardized tests to existing historic wood and steel windows for a preservation project. For this to be a rewarding experience, however, one must think before applying a boiler plate testing standard to a preservation project.

There are several agencies and organizations that are involved in the testing of windows and doors such as American Architectural Manufacturers Association (AAMA), American Society for Testing & Materials (ASTM), Window & Door Manufacturers Association (WDMA), Canadian Standards Association (CSA), and the American National Standards Institute (ANSI). ASTM for instance has drafted testing methodologies for windows and doors that evaluate specific performance metrics for the specimen. For example, an ASTM E2068 rates the force required to open a window, ASTM E283 tests for air infiltration, and ASTM E547 evaluates the water resistance of the window system. These agencies often work together in defining new standards. Back in 2008, AAMA, WDMA, and CSA combined to draft a standard that is widely used in North America called the 101/IS.2/A440. A full battery of tests on a window will include evaluating the window’s resistance to forced entry, structural integrity, deflection of the window under structural loads, resistance to water and air, and the force required to open the window.

So if these agencies have contributed so much to understanding the integrity of newly manufactured window systems, one would think that you should be able to incorporate similar testing towards the evaluation of historic wood and steel windows. Unfortunately, that isn’t always the case. Most historic wood and steel windows that were manufactured 75+ years ago were not designed to pass modern-day testing standards. That doesn’t mean they are unsuitable for the structure, it just means they won’t pass many of the current test standards. Air infiltration and water resistance testing are most commonly requested on historic windows. I will save you $4,000 and a lot of headaches by informing you that a 75 year old wood double hung will fail an AAMA 502 water test. You can minimize this effect by installing storm windows, but a redesign of the sill and weather stripping must be done if you are going to achieve modern performance levels on a water test. It is important, therefore, to understand what are the realistic performance expectations of your existing historic windows prior to considering applying a testing criteria to the project.

There are situations where testing of historic windows makes sense. We have found testing to be very valuable when you have a situation where the entire window system must be replicated. In these cases where everything is going to be replaced with a custom, one-of-a-kind window, this distinct design should be tested. Re-View has manufactured thousands of complete replica window units that match the original drawings of a historic building. We recommend testing any new design that hasn’t be subjected to the testing criteria in the past as a means to insure that the product engineering performs as anticipated. Since the tests are designed to subject the window under peak stress conditions, product design deficiencies quickly rise to the surface. We learned a great deal about adapting the design of the sash, glazing, frames, finishes, and weather stripping as a result of our many test experiences.

I thought it might be helpful if I shared some actual lessons we learned while testing windows over the years:

• The area where our frame jambs meet the sill had to be completely redesigned after a test many years ago because water penetrated this joint. Originally our means of sealing this joint was similar to very widespread industry practices. If it weren’t for the water test, we wouldn’t have known that this joint is a common weakness in many window designs.

• One would think that windows fabricated by large international manufacturers would easily pass a random water test, but we had catastrophic failure on a field test of a frame design of a standard product offering from one of the largest wood window manufacturers in the world. So don’t completely trust published testing statistics on existing designs.

• We have experienced immediate failure on water testing of standard historic double hung windows because the rise in the sill isn’t high enough to withstand the rise in the water when it is put under pressure during the test. That is why you see modern windows with a sill design that rises above 1-1/2 inches.

• We experienced glazing leakage very early in our history during a test that influenced a total redesign of our glazing design and methods of application. The results of this test inspired us to invest in automated glazing equipment, purchase different types of sealant, and redesign the glazing rabbit on our sash.

• We discovered that ballistic glass will fail if you hit the same area with a second round.

• Our engineering team enjoys pushing the tests beyond the standard criteria. It is quite common for us to take the tests to another level to push the window to a point of failure. We have learned a great deal about structural issues and water penetrations by amplifying the testing way beyond the published standards. It can be pretty alarming to see a massive window specimen literally blow up before your eyes when exposed to pressures many times the test standards.

• We conduct accelerated testing of paint finishes whenever we evaluate a different species of wood or alternative finishes. We also incorporate adhesion testing of field applied finishes as a quality control mechanism. Our plant uses non-destructive paint mil thickness testing as another QC tool.

Take a look at our Facebook page to see pictures of many of the tests we have conducted on our historic window designs in the past:

https://www.facebook.com/media/set/?set=a.405489146173765.95095.118211914901491&type=1#!/media/set/?set=a.405489146173765.95095.118211914901491&type=1

Scantily Clad Windows

What many of our customers don’t know is that the ownership of Re-View cut our teeth in the window business by selling and installing aluminum clad wood windows. We have installed thousands of windows manufactured by the largest window manufacturers in the world, including Andersen, Pella, Marvin, Eagle, and Weather Shield. Over the past five years, these manufacturers have made significant efforts to market their products as replacements for historic wood windows. Designers who are attracted to the prospect of low maintenance and energy efficiency are buying the message and specifying aluminum clad wood windows as replacements for wood windows that have lasted for 100+ years. Unfortunately, there is a serious problems with using aluminum clad wood window replacements in historic applications.


The big selling point for the aluminum clad wood window manufacturers is the concept of a low maintenance exterior. Clad windows are designed with an exterior skin of aluminum applied to the exposed sash and frame parts that has a baked on finish applied at the factory. The manufacturers use either roll-formed cladding or extruded cladding on their windows. Roll formed cladding is very thin which makes it easy to bend and form into tight shapes and profiles. It is less expensive than extruded aluminum since the material is so thin. Extruded aluminum, on the other hand, is much thicker and must be extruded through a die to create a desired shape. Extruded cladding is more impervious to denting than roll formed cladding. The cladding is typically connected to the wood through a clip system or other mechanical methods.

The marketing tune played by the large manufacturers includes never having to paint your windows again. This is a very attractive message for schools, courthouses, and offices that don’t have annual maintenance budgets for finishing. Unfortunately, most of the major manufacturers have catastrophic errors in their cladding and sash designs that seriously limit their life expectancy. You may not have to ever paint the aluminum clad wood window, but you will have to replace it within a 10-30 year timeframe.

The cladding on the sash of most of the window manufacturers is sealed to the glass with either a glazing tape or butyl sealant. Both of these methods have a 10-year life span at best so at some point, water is going to penetrate this seal. Many of the manufacturers recommend applying a cap bead of silicone to the sash to prevent leaks. Unfortunately, none of the major wood window manufacturers incorporate water management into their designs. The glazing pocket is typically unfinished wood that has only been surface treated with a wood preservative. There are no weep holes built into the glazing pocket to allow water to escape. Once water breaches the main seal, it will be contained within its built-in sarcophagus, accelerating the wood rot process. This major design defect is the primary reason the wood window industry is under attack. Just get on Google and type in “class action lawsuit against wood window manufacturers” and you will see what I mean about the wholesale wood rot epidemic eating at the heart of the industry. These wood rot problems have also fueled the growth of aluminum, vinyl, and fiberglass window alternatives.

Another problem with aluminum clad wood windows is how the sash design does not allow for replacing the glass. Although there have been outstanding quality developments in insulated glass technology over the past ten years, you can be fairly certain that the seal will break sometime within the first 30 years. The clad wood window manufactures build the sash around the glass making it virtually impossible to replace the glazing. The main reason these manufacturers do not incorporate a reglazing feature in their designs is that the glass provides much of the structural integrity of the sash. Once the glass breaks or fails, the entire sash must be replaced. Since these companies change the designs of their window products approximately every five years, the entire window will have to be replaced if the design is obsolete. It is almost like the major wood window manufacturers have built in a mandatory replacement mechanism to help sustain their business model into the future.

When one looks at the epidemic levels of wood rot for aluminum clad wood windows and the inability to replace glass on these windows, it is obvious that replacing a 100 year old wood window is not be the best course of action.

You can access our Facebook page to see pictures of these clad wood window designs and resulting problems.

https://www.facebook.com/media/set/?set=a.386861071369906.89473.118211914901491&type=1#!/media/set/?set=a.386861071369906.89473.118211914901491&type=1

Can't See the Forest for the Trees

Over the past five years we have seen a dramatic increase in specifications that demand the usage of Forest Stewardship Council (FSC) certified wood. This is a result of the FSC being the only organization recognized by LEED so the design community has adopted it accordingly. As a result, our company has been influenced to provide FSC wood on many projects. Like lemmings to the sea we all march with our FSC logos. Since the FSC has gained such widespread acceptance through its connection with LEED, I thought I would check into whether the FSC is really adding value. My take on the whole issue is that FSC has failed and has only succeeded in adding cost to the procurement of wood products.


I fully subscribe to the tenets of environmental stewardship. In addition to believing that all wood used in construction should come from properly managed forests, I also recycle, commute to work by bicycle, and even own multiple programmable thermostats. But seriously, our company is dedicated to working with established mills to assure that all of our wood comes from well managed forests.
If you look at the FSC website at www.fsc.org you will be bombarded with a very impressive message that states that we “shall promote environmentally appropriate, socially beneficial, and economically viable management of the world's forests.” After spending a couple of minutes on the site, one gets a warm feeling that the FSC is saving the environment, supporting underdeveloped economies, and improving labor practices across the globe. I truly felt proud about being associated with such a great organization after reading the vision and mission statements. That is until I looked into the major problems with the program.

Although the FSC has over 150 hectares of global forests certified currently, this only amounts to 2% of the world’s forests. It is estimated that approximately 85% of those certified acres relate to wood used in paper production. So the FSC influence is minuscule when one looks at wood used for building materials. Since LEED only accepts forest products certified by FSC, this organization has been perceived to be the gold standard in wood certification. What many people don’t realize is that there are many other credible certification programs available on the market today. The American Tree Farm System (ATFS), Sustainable Forestry Initiative (SFI), Timber Legality and Traceability Verification (TLTV), and Tropical Forest Trust (TFT) just to name a few. Currently the US Green Building Council (USGBC) is considering expanding the certification programs because the coverage of the FSC is so limited.

The FSC certification process also burdens the system with unnecessary costs. Not only does the FSC certify forest managers and owners, but they have a chain of custody (COC) certification for manufacturers and subcontractors who utilize certified wood. This means that small furniture manufacturers, casework companies, and millwork shops need to go through the cost and bureaucracy associated with securing and maintaining a certification. Since there is little to no policing of the certified parties to confirm they are practicing the proper utilization of certified woods, the certification amounts to little more than a right to use the FSC logo in marketing materials.

Some early adopters of the program have benefited from marketing the certification and are commanding higher prices in the marketplace. Not only is there an added cost for FSC wood due to the costs of certification, but this wood is being marketed as special when that really isn’t the case. Recently we purchased FSC certified mahogany from a mill. The cost of the certified wood was 20% greater than wood without a certification. The strange thing about this scenario is that the mahogany that was certified was the same mahogany that had no certification. The certified mahogany came with a three page document verifying the certification of the forest and all parties who touched it. In our current economy do we really want to add such a useless tax on the industry?

It seems to me that there is a better solution for creating a system where all wood used in construction comes from properly managed forests. There has to be a solution that doesn’t add needless cost to the industry and does a better job of policing compliance. A manufacturer shouldn’t have to spend thousands a year to maintain a certification when there are less costly ways to document that all wood was purchased from managed forests.

Don't Get Finished on Historic Windows

One of the most overlooked processes in a historic window project is the exterior finish. Many of the specifications that we see have an old paint spec cut and pasted from a previous project that references products that are 20 years old. There is little attention given to surface preparation requirements such as removal of old finishes, neutralization of strippers, moisture content of the substrate, or desired mil thickness. This neglect in using the best materials and proper means and methods has given window restoration a bad name and driven professionals to pursue aluminum or aluminum clad replacements to achieve a low maintenance finished product.


This post will address many of the challenges in finishing historic wood windows. If you follow the basic fundamentals of finish application, your historic window restoration will last for decades.

Neutralization

Most historic wood window projects involve the removal of existing finishes. Although there are several ways to perform this task such as steam ovens and infrared heat guns, the use of chemical strippers is most commonly used. If you use strippers, the stripper must be properly neutralized after existing paint removal or the new finishes will fail to adhere. Unfortunately, the lead-paint abatement function is sometimes performed outside of window restoration on commercial projects so the coordination of paint removal and neutralization is never achieved. We also see a lack of quality control in the field where no testing of neutralization is conducted as a matter of course. Re-View has learned that it is critical to test the pH levels of the window components prior to application of the primer. You want to use pH paper to make sure the wood has reached a level of at least pH7. We often will have to perform multiple neutralization applications if caustic strippers are used since they are absorbed into the fibers of the wood.

Moisture Content

There is nothing a painting contractor hates more than having to check the moisture content of the wood substrate prior to applying finishes. We like to have a moisture content of between 6 to 12 percent. Moisture readings in the high teens and into the 20s will cause the paint to crack or peel. We use a moisture meter made by Lignomat because it is quick and efficient and will test the moisture below the surface level. Sometimes it is challenging to achieve a proper moisture content on a historic window project. The wood can easily achieve moisture contents in the 20’s after neutralization of strippers. Rain on the project site can also contribute to higher than desired moisture readings on the window frames. Other conditions such as ambient temperature and the prevailing relative humidity can affect how long the window component needs to dry to achieve desired readings. We also find that windows located on the North or East elevations tend to dry at a slower rate than the South and West. Given all of these variables, it is understandable why the moisture content of the wood isn’t a cut-and-dried subject.

Surface Preparation

It also makes sense that the surface to be painted should be clean from debris, oil, mold, or dust. In this industry, however, surface preparation is often the most neglected function. We have seen many painters who will apply paint to most anything that doesn’t move. In fact, I saw a dead dog years ago that had a street line painted over it. Although proper surface preparation such as power washing prior to painting forces another step in the process and adds time to the project, it is an essential element to a long lasting finish.

Quality Control

Another step in the finishing process that is often neglected is quality control. We like to incorporate mil thickness and adhesion testing in all of our projects. The mil thickness test can be performed by using a non-destructive testing device that doesn’t damage the finish. Although this meter is expensive, it can be good insurance and forces the painters to pay attention to details. You might be able to gain access to this tool by asking your paint supplier. The adhesion test is another quality control process that can be accessed from the paint manufacturer. Our Sherwin Williams representative has been very helpful in conducting random testing on the adhesion of the finishes to assure proper surface preparation and finish application. A simple cross-cut test can verify if all means and methods have been correctly followed.

Although the content of this post is very elementary, we see far too many projects where the basics are often neglected. If you pay attention to the finishing fundamentals, your historic window finish will perform for many years. Click on the following link to see a slideshow about historic window finishing: https://www.facebook.com/media/set/?set=a.348985885157425.83223.118211914901491&type=1#!/media/set/?set=a.348985885157425.83223.118211914901491&type=1

The Makeup of the Mockup

I was in Birmingham, Alabama yesterday at a historic window mockup review and thought that addressing the importance of a mockup for preservation projects would be a good topic. Re-View is based in the “Show Me State” so we have always been believers in the value of a mockup.

The primary reason one would want to go through the extra cost and time of producing a sample historic window installation is to make sure the owner, architect, general contractor and window subcontractor are all on the same page. Misinterpretations of the scope of work can exist with any of these parties. These constituents might also learn something from performing a complete restoration of one window that might change the initial scope of work. The following are some actual examples of these types of lessons learned during the mockup process:

• We have had many projects where the scope of work called for restoring the existing frame and replicating the sash with an exact match to the existing in mahogany with insulated glass. The frame restoration called for removing loose existing paint, repairing the frame, and then finishing the frame in a matching color to the sash. When the mockup was produced, a new sash with a crisp factory finish and smooth surface was mounted into an old frame with a rough surface finish over the remaining lead paint. In some cases, the contrast of new to existing finishes are more than the owner and architect desire, calling for a change in frame restoration scope.

• On another project we had a requirement for an independent 6 pound water test to be performed on the mockup of an existing historic window. Unfortunately, there are few historic wood windows that were designed to perform at that level. In order to achieve that kind of performance the window needs to be redesigned, which often contradicts the historic intent of retaining the original look of the existing system. The independent test confirmed that a redesigned sill, stool, and weather stripping would be required. Be careful in applying modern ASTM testing standards to historic window designs.

• We had a project that called for laminated glass on a 12-lite over 12-lite double hung window. The specification called for including the mark found in the lower right corner of the glass designating the glass as safety glass. This mark is useful in a conventional one-lite window so the glass is easily confirmed to be laminated. To the project team’s dismay, we discovered how awful 24 glass marks look on a true-divided-lite window. The mockup was convincing evidence that we should eliminate the safety-glass marks on all window panes.

• A State Capitol project demanded historically correct ballistic windows in certain areas of the building that matched the other existing wood windows. The specification called for the window system to withstand a shot at 2,760 feet per second with a 7.62mm 150 grain, lead core full metal copper jacketed ball shot at a range of 15 feet. The construction team decided it was important to secure an independent test of a mockup to provide insurance to all involved that the custom design would in fact perform as required. This mockup helps shield the project team from the legal liability of product performance.

• On a courthouse project with four radius wings, we used two mockups to determine whether the glass and sash should follow the same radius as the building. We installed a flat glass sash next to a radius sash with bent glass in two windows. It was quite evident that the radius unit with bent glass was the preferred design based upon this visual test.

A mockup can also be very valuable for the window restoration subcontractor and the manufacturer of the historic replicas to learn how to perform the work outlined in the construction documents. In this business, every project presents different challenges and means and methods might have to be altered to achieve the desired effect. The construction documents might also be incomplete on certain elements that present themselves during the mockup process. We feel that learning these lessons before full-scale production work begins saves everyone a great deal of costs and headaches. The following are some actual examples of lessons learned from the mockup procedure:

• We had a steel window restoration project that called for a fluoropolymer finish paint combined with a linseed-based glazing putty. During the work on the mockup, we discovered failure of the paint adhesion on the putty. It is not uncommon to discover incompatibilities in paint finishes, putties, sealants, interlayers of laminated glass, and edge seals of insulated glass. Since these incompatibilities are not well documented by the manufacturers of these products, a mockup is a good way to determine whether the prescribed system will perform.

• Back in 2005 we restored 29 triple hung windows that had a sash opening of 8 feet wide by 24 feet tall. Each sash was 8 feet square with nine lites. The specification called for saving the existing glass and replacing broken glass with ¼” clear glass. As is typical of a project requiring the reuse of original glazing, a high percentage of the original glass was broken. The 91-year-old original glass had been permanently tinted by pollutants. The mockup we produced displayed a checkerboard effect where original polluted glass was matched up with new clear glazing.

• Many specifications call for restoring the existing locking hardware onto either a replicated sash with insulated glass or a restored sash converted for receiving insulated glass. We discovered during a mockup a long time ago that the original keeper that receives the sweep arm of the lock is too large to be reinstalled in the area that now has insulated glass. It is possible to purchase precisely replicated hardware to match the existing that has a modified keeper for just this type of application.

• There have been many instances where a manufacturer of historic replica windows failed to perform a mockup installation to test installation methods and fit within the wall cavity. We run across many different wall conditions with varying relationships from exterior masonry, interior framing, interior plaster, and existing trim.

Although a window mockup will add cost and delays to a project, it is certainly a worthwhile investment for all involved. Click on the following link to see pictures of these mockups on our Facebook page: https://www.facebook.com/media/set/?set=a.324097157646298.78668.118211914901491&type=1

The Great Debate

Re-View often gets dragged into the debate on what is the proper scope of work for historic windows. It is often a heated subject that is vented out at tradeshows, meetings, and internet chat groups. As is the case with any good brawl, the emotions often run high from all constituents.

Anyone who has been involved in a project with historic fenestration has had to confront the question of what strategy to adopt concerning the windows. There are two opposing camps that best define this debate on historic windows. The following definitions of the window manufacturer and the tree hugger are done in the extreme for dramatic effect:

The Window Manufacturer: This group has one goal and that is to sell more windows. Profitability of the corporation and market share are paramount. As a rule, this group is more interested in increasing volume than doing what is right for the building. Attention to historic detail, performance, and quality are only considered if they are deemed contributory to the bottom line. The use of attractive photographs, slanted test results, and mass advertising has enabled this group to establish a strong influence.

The Tree Hugger: The biggest regret for this group is that they didn’t make it to the Woodstock concert back in 1969. They are extremely passionate about retaining historic fabric on a preservation project. All means, methods, and materials must be focused on restoring the window system back to its original form. Any deviation from that course is an abomination. Since this group is so fragmented and lacks the sex appeal or the marketing budgets of the manufacturers, they often remain the soft voice in the debate. If one listens to their common sense position on the subject, however, the message is very compelling and powerful.

So if you are an owner, architect, or general contractor how do you make sense of these diametrically opposed viewpoints concerning the subject? Do you replace your historic windows with new units, or do you restore every element back to its original state? The answer to that question depends on a number of factors such as the historic significance of the property, the use of the building, the budget, and the construction schedule. It also depends upon where the owner and architect land on the debate spectrum.

I am a firm believer that it helps to have input that is void of emotion to assist in determining an opinion on this subject. Unfortunately, there are few unbiased studies that exist on the topic. If you ask the manufacturers for data, they will produce internal test results that allege 74% energy savings with their products and claims of no future maintenance. If you ask the tree huggers, they will argue superior performance through complete restoration combined with a storm window and pull out the social responsibility card.

We have seen an independent study that is worthy of consideration. Robin E. Whitehurst and Susan Turner of Bailey Edward authored a study in 2009 that evaluated different treatments for windows at Lincoln Hall at the University of Illinois. The study compared replacing the windows with aluminum clad wood units, restoring the existing windows and retrofitting them with insulated glass, and adding a storm window to a repaired window.

The three courses of action were evaluated on energy performance, initial cost, maintenance costs, life cycle costs, and effects on the historic fabric. The study makes for good reading if you are wrestling with how to attend to historic windows on your project.

You can access the study through the following link:

http://www.illinoishistory.gov/ps/Lincoln%20Hall%20Window%20Life%20Cycle%20Study%202008%20%20Univ.%20of%20Illinois%20at%20Urbana%20Champaign.pdf