Seeing Right Through Retrofit Windows


Retrofit windows, being a very popular home upgrade, have become a huge industry in the western United States. It is easy to understand why homeowners find it enticing to install retrofit windows on their homes. Retrofit windows can be a very cost effective approach to replacing old aluminum windows. In many cases, retrofit windows can be a fraction of the cost of installing a nail-on type or “new construction” window on an older structure. Retrofit windows are a much less evasive means of installing new windows, they provide an updated look to your home and when installed correctly can provide significant energy savings. However, the problems that could occur and more importantly the problems that (more often than not) get covered up can greatly outweigh the positives.

Aluminum Windows and New Construction
To start with, it is important that we understand what is protecting a structure from the elements. Common single and multi-family dwellings in California are constructed of wood framing covered by a primary moisture barrier that is typically asphalt impregnated construction paper or felt integrated into window and other wall penetration flashings which are applied together in a manor to shed water out and away from the structure. There are a wide array of products used in this application and is a whole different topic of discussion all together. The secondary moisture barrier is the exterior finished surfaces that consist of or a combination of stucco, brick, vinyl, various wood products and more recently fiber cement exterior claddings. These exterior materials are applied in a way so that vapor and moisture that finds its way beyond the exterior finishes will drain off of the primary waterproofing and away from the building.

Aluminum windows are secured to the building by fasteners and the use of sealants through an integral nail-fin that is a part of the aluminum window frame. The window is integrated into the window flashings and thus is a very critical part of the primary moisture barrier. As with any window installation, it is extremely important that these components are installed correctly to avoid future leaks.

However, aluminum windows (as with anything) have a serviceable life, which can vary depending on the quality of the product, installation techniques, weather exposure, earth movement, etc.  Aluminum windows have a history of failing at the corners among other things, which in many cases allows moisture to penetrate beyond the primary moisture barrier. This type of water intrusion is often unseen until a great deal of damage has occurred..

How Retrofit Windows Work
Before considering retrofit windows, it is a good idea to understand how they are installed. The existing glass and any obstructing mullions are removed from the existing window, leaving the old aluminum frame in place. The new vinyl retrofit window having a wide outer flange is then slid into the old existing aluminum window frame with the retrofit window flange being embedded into the bead of caulking. The wide vinyl flange covers the old window frame and is sealed with caulking once again around the perimeter of the flange to the building surface. The gap around the interior window perimeter is insulated (such as with an expanding foam) and trimmed with the appropriate materials depending on the existing interior surfaces.

Look Out
The caulking around the flange of the new retrofit window is generally the first area to fail. Once it has, what we are left with is the old aluminum frame, its old paper and flashings (if it exist) to protect the building. How do we know if these components are doing their job or even exist if we do not expose them?

The life of the caulking used at the retrofits windows exterior perimeter greatly depends on the quality of the product being applied, how it is prepped for application, weather exposure and if it is regularly inspected and maintained. Lets face it, regular inspection typically does not happen and damages usually goes unseen until a big ugly water stain on the ceiling, green fuzzy stuff on the wall, strange mud tubes climbing from the floor, or mushrooms growing out of the carpet somewhere in the vicinity of the window are noticed. The point is, when things go this far, the damage that we cannot see is usually far worse and extremely expensive to fix, not to mention the headaches that it can cause for the homeowner and in some cases the homeowner association and management. In the end, the costs are staggering as compared to what it would have cost to put in a new construction or “nail-on type” window in the first place!

Are Retrofit Windows Right for You?
Here are some considerations when choosing between a retrofit window and a new construction window. Are the windows being installed on a multi story dwelling? Is there enough cover provided by the building so as to allow minimal moisture contact during a substantial wind driven rain? Will the existing exterior cladding last as long as the new window? Is there a history of leaking windows at your home or in your community?

It is understandable that single-family residential homeowners as well as condominium, townhouse, and planed unit development associations find the cost of retrofit windows to be very enticing. However, in most cases, the retrofit window salesman is not going to educate a homeowner on the pitfalls of their product. So, having the foresight and knowledge to make the right decision for your type of structure can save you thousands of dollars down the road.

And remember, regardless of the type of window being installed, proper installation is absolutely critical to the performance of your new window. Improperly installed windows will not perform to their designed optimal life and become an overwhelming financial liability to homeowners and communities.

SPACE Sample Images

In these images, an infrared survey was conducted during daytime hours to reveal a central area of a ceiling that is saturated with moisture and in need of immediate repair.

In these images, an infrared survey was conducted because of a continued electrical issue which caused the breakers to trip. The 110 Amp circuit breaker, B phase exceeds 80 percent ampacity and the temperature exceeds the breaker rating, causing the breaker to trip.
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