Gutters & Exterior · 5 min read
House Wrap and Flashing: What's Behind Good Siding
Published
Siding is a rain screen. Some water always gets behind it. What keeps your walls dry is the drainage plane underneath.
How house wrap works
It's installed shingle-style — upper courses lapping over lower — so any water reaching it runs down and out rather than in. Seams must be taped, and staples alone in high-wind areas will let it tear.
Window and door flashing
This is where most siding jobs fail. Sill pan flashing, jamb flashing lapped over the sill, and head flashing lapped under the wrap above are all required for water to actually exit. Caulk is not flashing.
Rainscreen gaps
A drainage gap between wrap and siding lets the assembly dry. Fiber cement and wood benefit substantially; vinyl's profile provides some inherent drainage.
Why you should care
You'll never see any of it after installation. That's exactly why it's the first thing a contractor skips under schedule pressure, and the first thing you should ask about.
If any of this applies to your own home, our siding installation crews handle it every week, and you can see how we work in your area on our Troy, Ohio roofing page. Inspections and written estimates are free either way — call 937-749-7767.