Flash-and-fill or just seal well and fill?
Hello, We are talking about building a pretty good home with a local contractor in a semi custom solar ready community. I am of the mind, we should reduce energy consumption before adding solar, but the builder is trying to create an affordable option for the average person.
I appreciate and respect what he is trying to do. That being said, I have been pushing him to make our potential home more efficient than the average house in our community. I should start with, we are in climate zone 5. It is a moderate climate generally and very dry here.
Currently his wall assembly is 2×6 24 on center, sealed with spray foam and netted blown in cellulose with sheet rock on the inside and osb sheething, tyvek, lab board siding. They are carefully sealing headers, footings, cutouts, ect and have blown 3.0 ach/50psc. Not fantastic but much better than the average home being built here.
I have challenged him to add 3 inches of ridged board to the outside of my home 2.5 in. being the minimum according to my calculations of 27% in the outside for our climate zone and minimum precipitation. R23 in walls R9 or better on the outside to avoid dew point problems.
He is also doing a partially conditioned crawl space and has agreed to a fully conditioned crawl for our house, upgrading to spray foam around the perimeter for better insulation and sealing. He also agreed to go from a typical gas hvac to a minisplit system. We are currently debating water heaters but he has also agreed to helps us fit our water heater within our conditioned space.
He will not budge on windows so they are typical windows (hopefully) well sealed and installed. Surprisingly most of our bigger windows will be south facing and I plan to add overhangs at some point to reduce summer sun, helping a bit in the winter passively. The ceiling will be well sealed and have R50 blown in.
Back to walls, I proposed 3 in. ridged foam out board of the osb sheathing with furring strips. My contractor said that option is very expensive in out region due to availability. He is suggestion 2 in. spray, flash and bat. Or a zip sheathing option with insulation (I need to clarify this option). I appreciate any and all suggestions. I would like this pretty good house to be as efficient as possible with out blowing our current budget.
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