Installing Window in Concrete Wall
I am looking for ideas on how to air- and water-seal a window in this concrete wall.
We are doing our best to build an energy-efficient house. The remainder of our windows will be installed in wood framing, and we already have the details planned (see attached photo). The contractor planned this window detail without me, and it appears that it will be installed as an “innie” window on the concrete buck that was poured… and will be “through-frame installed into the concrete.”
Our other windows will be installed on the outer 1/3rd of the wall framing with zip sheathing and exterior foam insulation. We will be using zip stretch tape for the sill and zip tape around the remainder of the stud frame for water sealing.
This window was originally planned to not have siding on the exterior and leave the concrete showing. I don’t see how this is possible if we are using a liquid applied flashing (like Prosoco) and using other products to air-seal around the exterior of the window because you will be able to see these products.
I can’t find a detail online, other than applying spray foam around the window and I am not ok with this method, as it is prone to air leakage.
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Replies
Not the most ideal..
Cover the concrete outside the window frame by like 1.5-2" polyiso and run the siding on top of that around to the frame of the window. Basically use the whole frame height as room for insulation and siding/stucco (which might allow more insulation).
This is not ideal but the best you can do. Optics will suffer or energy...
If possible seal concrete against the frame and the polyiso to the frame again (backer rod + silicon) to have two water repellent layers to the frame.
If you want, apply fully adhered WRP from outside of the wall around the opening to inside of the frame to prevent moisture through the concrete wicking out - maybe a bit overkill but then you have the sealing faces for the window install like in all other places.
regards
I am curious what you would have done to mitigate this if you planned this directly? If it would be not to have the buck, can you not just cut the concrete lip off around the perimeter and seal from the inside as needed?