Guidelines to Full-Frame Replacement
When I presented replacement challenges in the March/April issue, I focused mostly on full-frame replacement. Most agree this is by far the most difficult replacement scenario. Requirements for structural performance, and stopping air infiltration and water intrusion, depend on the installation, but are even more difficult to satisfy in this case. In many circumstances, however, full-frame replacement is the only good replacement option. This usually leads to several additional concerns.
Dealers and installers would do well to frequently check with their fenestration manufacturer―and manufacturer of weather barriers and sealants―for available new instructions for full-frame replacement. The continued release of this information will continue to grow, and some brands have quite a bit available even now.
Conversely, if you’re a manufacturer with these instructions already available, push that information to your installers. Don’t leave it on the table or hidden on your website. Push it out to the field. You’ve invested a lot of resources in these materials and getting it in the hands of the people who need it the most will benefit everyone.
If you’re an installer and instructions are not available, consider the following guidelines and concepts before you propose your replacement project. This is not intended to lead an installer into an installation he is uncomfortable with. The best guideline might be to not perform the replacement at all.
1) The biggest hurdle in full-frame replacement is preventing wa ter intrusion around the installation perimeter.
Pressure differentials between the interior and exterior can draw water through small penetrations, just like sipping through a straw, especially in more extreme regions and newer, tighter homes. The installation perimeter can be the weakest link. Your goal is to interface the fenestration with the membrane, or surface barrier, if possible. From a practical standpoint, this might not be possible. At the very least, do what you can to deflect water from the rough opening or lead it back to the exterior with drip caps, thruflashings and sill pans.
2) Consider the entire wall and its components as a system.
Whether it’s a surface barrier or membrane drainage wall structure, many elements work together to prevent water intrusion: flashings, sealants, fenestration, exterior veneers, and related components. A failure of any of these components can result in water emerging at the fenestration. Consequently, an examination of the entire wall condition should be taken into account before and during fenestration replacement. I’ve even seen a roof leak and improperly installed gutters cause water to trickle into the wall and down to the interior of fenestration.
3) Consider entire facade replacement at the same time as fenestration replacement.
Obviously, this will add substantial expense, but there are situations when this is justified, especially where siding is decaying or no weather resistive barrier exists. Replacing the entire facade enables a new construction installation practice with a proper new membrane, flashing and unquestionable results.
4) Consider risk factors.
Eliminating the risk of underperformance, air infiltration and water intrusion is the ideal goal. Many issues factor into the risk level. Minimizing these risks is the next best thing and should be considered in less-than-ideal fullframe replacement situations. Some risks to consider include:
- Regional weather: wind speeds, rain amounts, climate
- Exposure of the fenestration: orientation to incoming weather, soffit and overhang protection, tree protection (wind break)
- Elevation: Higher up means higher wind speed
- Existing structure: Does it have a weather resistive barrier for the membrane drainage system, and is it in good condition? What is the façade condition? Will you have full access to the nail fin by removing casing or cutting back siding?
- Replacement product: Are you replacing with the same frametype product or is some adaptation needed?
Installer’s skill level and experience: This leads to a “comfort level” discretionary call by the installer or contractor, and in some cases, I discuss it with the client. I’ll warranty the fenestration installation but not the entire wall system. Full disclosure up front is much easier than “excuses” after the fact.
In the end, with or without written instructions, you must have confidence in your replacement and be able to stand behind it.