Fast and cheap doesn’t always equal bad, just most of the time…
What do you see wrong with the pictures below? I see potential building failure…
1. Interesting timing to install one’s windows. Before, adding your water resistant barrier (house wrap)…
2. All windows will eventually leak, and this window is no exception. Unfortunately there is no sill pan installed below this window (they stopped at the nailing-fin). Consequently, the frame and sheathing will likely experience water intrusion (I’m guessing within 15 years). I’ve never seen this particular building sequence before.
3. Felt paper (the black stuff), is being installed under the stucco (fairly typical), but wait, where is the WRB (house wrap)? That lone layer of 60lb felt paper is going to deteriorate over time, especially when sandwiched up against warm moist stucco. Wood eating insects are attracted to wet wood…not good!
Better practice would be to:
1. Use a higher tier WRB instead of the cheapy felt paper. Use specified tapes and sealants to make that WRB into an air-barrier too, keeping warm humid air (a potential source of condensation) out of the wall cavity.
2. Slope all the sills on of the rough openings at least 5 degrees, sending water (entering from a leaky window frame) outside rather than inside the wall. This one’s so easy, but I’d bet less than 5% of builders do it!
3. Add a window sill-flashing with a sealed backer rod, keeping water out of the wall and onto our WRB, where it can harmlessly dry out without causing damage. This belt and suspenders waterproofing approach, also helps us with air sealing.
3. Employ the use of a 3/8″ thick rain-screen, providing the future stucco a capillary break and air-gap. The rain-screen keeps bulk water off the WRB, and allows the stucco to dry out from front and back. Because the stucco will remain less damp year round; peeling, cracking, and vapor drive into the wall are all significantly reduced.
Spending a little extra time and money up front, to get the waterproofing details right, could extend the life of any building by two to three times (or more). We like to think in terms of building homes for a bare minimum of 100 years.
Wait, didn’t we see the long term effects of a similarly fouled up felt paper install on my last blog post?…but at least that install didn’t involve stucco cladding. Yikes, I seriously wonder how long this home will last?
Doug Cameron is a Healthy, High-Performance Builder & Remodeler with EcoSafe Spaces in Austin, TX.