Exterior foam wall sheathing vs flash & batt
I saw an article by Steve Easley about changes coming in the 2021 IRC for wall insulation and I’m wondering about what current options are going out the window. Any insight from fellow GBA readers would be appreciated.
Continuous exterior insulation on walls – I’ve been using flash & batt on walls and it works great, even though there are still thermal bridges at studs. The effective total wall insulation is more than adequate. It makes for an airtight wall. And vapor control works in all climate zones. My designs are stock house plans that can be built in any climate zone, so I need solutions that require only minor adjustments between zones. Flash & batt fits the bill.
A downside of exterior foam is the complications it adds to waterproofing door and window openings (significant labor expense), as well as installation of heavier exterior finishes such as cast stone veneer and stucco.
An alternative is Huber Zip-R sheathing, IF it can satisfy shear wall requirements for seismic zones. I don’t like to use vendor specific products though. Other companies need to start producing similar panels.
What are your thoughts with regard to 2021 changes and the above?
Will flash & batt still be a code viable solution?
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