Rainwall performance in windblown rain
Looking at using “rainwall” siding (vertical 1 by bats under the siding) on the Oregon coast. I plan to tie the vented area behind the siding on into the soffit and then venting the roof as well on through ridge venting.
Am I asking for trouble or avoiding it?
Replies
What's your proposed detail at the bottom of the siding?
I'm thinking of the problem of stopping bugs, bees, etc., getting in behind the siding while allowing the necessary air intake to maintain through ventilation.
IanDG
The wall frame is sheeted with 1/2" cdx, then covered with 30# felt, lapped 2" (local contractors have found that Typar et al is inadequate), then staple a strip of stainless screen all along the bottom of the wall, then nail 1x4's vertically at each stud location and around windows and doors, then fold the screen up onto those bats and begin siding.
Wog
Sounds like a very good spec. --- the thing to avoid is a 'dead' area with no through ventilation, such as below windows, where condensation can give you a rot problem.
IanDG
>> ... the thing to avoid is a 'dead' area with no through ventilation ...
So do you put a vent under the window sill, or leave gaps in the furring strips so the air can move sideways and go around the window, or what?
Put a horizontal strap under the window and keep the verticals a couple of inches short.
Around here you can get a rigid perforated 'J'mould for the bottom thats easier to work with than bug sreen.
Rain wall detailing is almost mandatory here now since the' leaky condo crisis ' of the last decade or so and the virtual collapse of the home warranty plan.I recommend it on walls with harsh exposure to the elements.
...............Rik...........
Thanks for the vent-around-windows pointer. This "J mold"----that some sort of vinyl piece? It'd be invisible and out of the ultraviolet.
On the Oregon coast wind can blow unbelieveable amounts of rain horizontally and even vertically, and the negative pressure created behind walls and inside structures and structural elements will suck water inside. Really a challenge right on the ocean. Do you think the rainwall could become a suck chamber?
The Jmould is apiece of perforated aluminum comes in ten foot lengths. Iv'e had the same stuff custom bent for soffit venting on custom homes.I'll try to dig up a piece at the job tomorrow and post a pic if I remember.
The rainwall won't be a suck chamber as long as all yer windows and stuff are detailed : we use peal and stick to the building paper(double layer 30 min)outside and caulk(satan pitch)to the vapour barrier inside.
When you make a house this tight you MUST make sure you ventilate and have proper amount of air changes per hour and all that fun stuff - thats for someone else to answer.
We only do this detailing on oceanside homes or homes with lots of exposure.
...............Rik..............Victoria BC
Here is a couple of pics of the perforated aluminum I was talkin about.
.............Rik............