How much through-wall flashing needed with full-thickness masonry?
I am about to clad my structure in full-thickness limestone veneer, and I’m getting conflicting advice about what constitutes proper through-wall flashing. Would appreciate feedback from anyone with experience in the matter.
From outside to in, my wall system is 3″-5″ thick limestone, 1″+ air gap, HomeSlicker with Typar (a drainage mat/WRB), then a liquid applied weather resistive barrier on OSB sheathing. Using Textroflash for the through-wall flashing at the base of the walls and tops of windows. It’s a self-adhesive 40-mil composite membrane.
Anyway, the masonry supplier who sold me the TextroFlash says it serves perfectly fine as a durable through-wall flashing. It comes with instructions, though, that say a stainless-steel drip edge flashing must ALSO be used underneath the TextroFlash. Supplier scoffs, says that is pointless overkill to double up the flashing.
Feedback?
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Replies
Andy,
You need the stainless-steel flashing, for two reasons:
1. You only build this wall once. If you have to remove the limestone to correct a flashing problem because your wall is rotting, the repairs will cost more than the entire cost to build your house. It's happened. (In addition to the cost of the repair work, the lawyers have to take their cut.)
2. You always have to follow manufacturer's instructions. That requirement is part of all building codes. Installing any material in a way that does not comply with the manufacturer's instructions is a code violation.