Oregon Rainscreens

[Bill Robinson]

OK, what's the skinny with the rainscreen requirement.

What successes and failures have you seen and how is it working?

[Lavrans]

Well- I'm seeing a lot of people just not doing it. They aren't enforcing, or aren't enforcing very strictly. The last job I did the city gave a handout, but weren't very interested in showing up for any of the inspections, and certainly didn't come out to see the rainscreen... and opted to just believe me when I told him it was there.

BTW, it's a pretty minimal rainscreen requirement. DOW, et al, got their crinkle wraps ok'd as a "rainscreen". Because, you know- they sorta are 1/8" before you start installing siding, right? ;-), ;-)

I don't expect to see too many failures for another 2-3 years.

[dgbldr]

How about you explain to the rest of us unwashed pagans what you're talking about?

Does Oregon have a legal requirement for rainscreens? What is it? Code quote?

Thanks

Edit: Oops, posted same time as Lavrans. Still interested in details.

[Lavrans]

Yes- we have to use a "rainscreen". The original proposal required a 1/2" gap. That got reduced to 3/8" and then, after a blitz of glad-handing by the various crinkle & bubble wrap guys, it became a 1/8" or accepted product sorta rule.

There is an option that allows you to not use a rainscreen, and that's to use a double layer of #15 felt paper with through flashings under all doors and windows.

It's pretty "tough". wink, wink. nudge, nudge.

[dgbldr]

So this rainscreen is required regardless of exterior cladding/finish?

[Bill Robinson]

From the Oregon code.

To promote building durability, the exterior wall envelope shall be installed in a manner that water that enters the assembly can drain to the exterior. The envelope shall consist of an exterior veneer, a water-resistive barrier as required in R703.2, a minimum 1/8 inch (3 mm) space between the water-resistive barrier and the exterior veneer, and integrated flashings as required in R703.8. The required space shall be formed by the use of any non-corrodible furring strip, drainage mat or drainage board. The envelope shall provide proper integration of flashings with the water-resistive barrier, the space provided and the exterior veneer. These components, in conjunction, shall provide a means of draining in water that enters the assembly to the exterior.

[dgbldr]

The required space shall be formed by the use of any non-corrodible furring strip, drainage mat or drainage board.

Normal brick veneer installation doesn't meet that rule.

[MarkMc]

Neither do log cabins. If anyone were building a new house around here I'd go look, but they aren't but they are thankful stuff rots dependably.

[Bill Robinson]

How about you explain to the rest of us unwashed pagans what you're talking about?

Does Oregon have a legal requirement for rainscreens? What is it? Code quote?

Thanks

Edit: Oops, posted same time as Lavrans. Still interested in details.

Interesting response, do you feel washed now?

[dgbldr]

Yes I do. It's always good to post enough info so that non-insiders can enjoy the conversation. Thanks.

[Bill Robinson]

Yes I do. It's always good to post enough info so that non-insiders can enjoy the conversation. Thanks.

How can I be an insider if everyone knows?

[eightinchnails]

Most of the new projects around here are just ignoring it and a lot of the remodel ones as well. As in everything the rules are only as good as the enforcement or and I hate to say it but attorney's litigating compliance.

[NW Architect]

Bill, you failed to post all the Exceptions that are in that section.

OK, what the deal is is: Oregon had a lot of leaky buildings. Almost all were due to bad detailing around the windows and penetrations, to wit, non-compliant with the then-prevailing code. The code requirements we're all familiar with. Senate committee established, testimiony taken, and a lot of that testimony from building code dudes from British Columbia. So, now that one has spent the money for all this study, there needs to be a result, and that result is language in the Oregon Residential Specialty Code.

Its bad legislation IMHO since properly detailed buildings weren't having troubles in the first place. AND MORE IMPORTANTLY half or Oregon is high desert with a very dry climate. Then, as Lav has pointed out, the housewrap people got involved and got in the exception for drainage-enhanced WRBs.

Oh, and its only the ORSSC, not the regular old building code aka the Oregon Structural Specialty Code. So the requirements only apply to one and two family dwellings. Condos and multi-family, where all the problems were found, are unaffected by the code language.

Oregon codes are available online as read-only pdfs. Google Oregon Building Codes, and you will get there.

As to the log cabin reference, read your IBCs and IRCs in detail. Most of the old exceptions are gone. Irrespective of cladding type, and whether or not the building is intended for human occupancy, you must have a weather resistive barrier in the wall system. Only exception is for cladding systems tested to be water tight to a specified performance level, and masonry.

Pole barns, pre-engineered metal buildings, log cabins, carports as we knew them are no longer legit. Code revision needed - just bring back most of the old exceptions.

And, while I'm on my soapbox, the IRC IBC language about flashing of projecting trim deletes the word wood. So now you must flash all projecting trim, not just projecting wood trim. And "trim" and "projecting" are still not defined. A literal application means that if I put terracotta tiles around windows in my brick veneer wall, and that terracotta is in a different plane from the brick, then I need sheet metal flashing over the terracotta. BS. Continue reading the flashing section in the newer codes and tell me how some of those other flashing requirements can be met.

[Bill Robinson]

Bill, you failed to post all the Exceptions that are in that section.

My alleged failure allowed you to get something you obviously needed to get off your chest.

Feel better now?

[NW Architect]

And I feel much better as a result. Thanks, Doc!