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Historic windows, repair or replace?

With the new energy efficiency mandates issued by the White House, numerous consumers are faced with the question of what to do about the historic windows in their homes.  If they are leaking and need repair, what is the better option to pursue?  Repair or replace?

Repair:  if your historic home is in a historic district (under local or state designation) the best option is to repair the original windows, so that you will remain in compliance with the preservation ordinance.  Inspect your windows from the exterior to determine the extent of the repairs that are needed.  If the glazing around the glass is cracked or missing, that is your primary cause of cold air leaking into the house.  

Methodology:  Carefully remove the damaged glazing with a putty knife. A small steamer can be used to soften up stubborn spots of glazing. Be careful to not get it too close to the glass, as the heat can crack the panes.  If you accidentally crack a pane, your local glass dealer can cut new pieces for you, and it is relatively inexpensive to do so.  If you have windows with hand rolled glass (giving a wavy texture and slight visual distortions when looking through it), you can ask your glass dealer for salvaged pieces of historic glass or a reproduction historic glass.  For example, Restover is one such brand that is available on the market.  When applying the new glazing, angle the putty knife at 45 degrees to creat a slope so that rainwater will shed off the window and not pool along the wood rails of the window. 

Next, you will want to inspect the condition of the wood framing around the window.  If the paint is peeling or missing, you will need to scrape and sand the wood to get a good clean surface.  If there are areas of rot, there are several good wood composite products on the market that can be applied to the rotted areas to reinforce the wood framing.  Once the composite material has dried and hardened, it can be sanded smooth.  Next, apply a good coating of exterior grade primer followed by two coats of exterior grade paint.  Also, if you have wooden storm windows, these repair methods can be applied to them.  If the frames of the storm windows do not seal tightly in the window jambs, weather stripping can be installed along the edges to seal any air leaks.  Your local hardware store can help you obtain any of these products.  Remember, a properly maintained wood frame window will last at least 50 years, which is five times the length of time a vinyl window will last.

Replacement:  If your home was built during the 1950s or 1960s and has aluminum framed single pane windows with no storm windows, replacement is a better option.  Aluminum windows conduct heat and cold at a high rate thus making them inefficient.  If your home is in a historic district, obtain a copy of the historic preservation ordinance to find out what the guidelines are for replacing windows.  Copies of the ordinance can be obtained through your local or state government agencies.  If the ordinance requires an alteration to maintain the character of the original design, new windows can be fabricated to match the designs.  An application for a Certificate of Appropriateness will need to be filed and approved by your local or state agency.  If your home is not currently in a historic district, one should consider the possibility of future designation of your neighborhood as a historic district.  Therefore, the impact of the alterations to the integrity of the character of your home should be considered.

Frequently lower end vinyl windows have been installed in older homes to increase energy efficiency.  These windows have their own set of problems.  Vinyl becomes brittle over a period of time and usually will only last a maximum of ten years before cracking and failing.  Usually the first place they crack is in the tracks the windows traverse when opened or closed, thus restricting their movement and creating air leaks.  Another frequent problem with these type of windows is the failure of the seal between the panes of glass sandwiched together to stop air from penetrating the home.  Argon gas is used in the seal to keep the window panes clean from the inside.  Once this seal is breached, the glass becomes cloudy from condensation and is impossible to clean, thus creating an unsightly and annoying problem.  A much better option for a replacement window would be another wood frame window, or a wood frame with a fiberglass or composite exterior.  if you are the type of person that really objects to painting the exterior of your home, the latter option may be your best choice.  Another point to consider is the warranties on replacement windows.  Many manufacturers are offering "Lifetime Warranties."  Read the fine print on the warranty to make sure it means the life of the home, and not the life of the window.  If the latter applies, do not buy the product, as you will have to bear the expense of replacing those windows five times over a 50 year period, which is much more costly than repairing your original wood windows.

To see a historic window restoration project, visit my website, A History of Color

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