Is a rain screen ever needed behind vinyl siding?
MikeonLI
| Posted in General Questions on
Homeowner in Long Island ny. I live in a house with very few overhangs that doesn’t get a lot of sun in a part of country that gets a good amount of rain.
I’m planning on getting new siding and I am likely going to go with vinyl. I know that usually a rain screen is never used with vinyl siding but are there any situations where it’s a good idea? What about for vinyl siding that has foam insulation attached to it? Thanks!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
If by rainscreen you mean a gap behind the vinyl created by vertical firring strips or some kind of mesh, then no, vinyl siding does not need this. Spend your time and money on the WRB membrane, upgrading it if necessary and making sure it's properly flashed at all openings.
Thanks Andy!
Mike,
I agree with Andy. Vinyl siding is inherently vented, but can let some water through from the outside, so a good WRB and flashing details are important.
While a rain-screen behind vinyl may not be needed, it is required in some jurisdictions (like ours) which mandate that any cladding must have a clear drainage path behind it.
Malcolm,
Thanks! What specific flashing details are required for vinyl siding that are different from other claddings? So do you recommend the rain screen even though it’s not required because it’s inherently vented as Andy says?
Mike,
Nothing different or specific to vinyl, the details just have to be done with more diligence as any mistake can get punished, where with a full rain-screen you might get away with them.
Rain-screen strapping makes any wall assembly more resistant to moisture problems. I'm not sure all vinyl siding manufacturers allow installation on strapping though.
Thanks Malcolm. Final thing.
Is a drainage mat as a rain screen a good compromise for vinyl?
Second, what about continuous exterior insulation plus a drainage mat and then vinyl? Thanks!
Mike,
It doesn't appear a drainage mat adds much.
https://www.greenbuildingadvisor.com/question/is-it-a-good-idea-to-use-a-drainage-plane-behind-vinyl-siding
I think sticking with good WRB details done diligently is probably your best bet.
Thanks so much Malcolm!