Rainscreen wrap issue

[OneWorld]

Hi, we have a project where we are using a rainscreen. We have cement board siding over a Benjamin Obdyke rainscreen mat. The wrap for the building was supposed to be roofing felt paper. Our contractor has told us that that our peel-and-stick flashing will not adhere to the building paper and wants to use a TYVEK product instead (something called Stuccowrap - described by TYVEK as a "water-resistive" wrap). We have always been concerned about water wicking through TYVEK and used roofing felts instead. Has anyone had issues with water wicking through TYVEK? Also, has there been issues with peel-and-stick flashing adhering to roofing felts?

Thanks for your comments.

Ken

[Bill Robinson]

Hey wait a minute, are you a construction pro?

The phrase "our contractor" makes me wonder.

FYI, I am adamant we do not engage with homers openly on this section of the forum. It is about supporting construction pros,so, what is your story?

Technically roofing felt is the wrong product. That said if it has worked in the past there is no reason to believe it will work in the future.

Compatibility is the game here, ask the roofing felt manufacturer what they recommend. If they don't then consider you are using the wrong product.

Moisture will wick when certain conditions are met, most of them should be addressed with the rainscreen.

It is the custom here to let us know a bit about your place in the world and all that jazz.

A self introduction of sorts.

[Mark Parlee]

I have seen water permeate through roofing felt and rot out the OSB roof sheathing below it

[Dick Seibert]

Technically roofing felt is the wrong product. That said if it has worked in the past there is no reason to believe it will work in the future.

Technically asphalt felt is the only approved product, Tyvek and other plastic wraps are not in the prescriptive code and must be approved under the alternative methods and materials section of the code.

R703.2 Water-resistive barrier. One layer of No. 15 asphalt felt, free from holes and breaks, complying with ASTM D 226 for Type 1 felt or other approved water-resistive barrier shall be applied over studs or sheathing of all exterior walls. Such felt or material shall be applied horizontally, with the upper layer lapped over the lower layer not less than 2 inches (51 mm). Where joints occur, felt shall be lapped not less than 6 inches (152 mm). The felt or other approved material shall be continuous to the top of walls and terminated at penetrations and building appendages in a manner to meet the requirements of the exterior wall envelope as described in Section R703.1.

Exception: Omission of the water-resistive barrier is permitted in the following situations:

1. In detached accessory buildings.
2. Under exterior wall finish materials as permitted in Table R703.4.
3. Under paperbacked stucco lath when the paper backing is an approved water-resistive barrier.

[Ted S.]

Years ago, pre 2000 prior to the change in energy codes here in MA we would use saturated felt in a brick veneer cavity wall. It was that way for decades. Last I remember we routinely used peel and stick flashings adhered to the felt. I believe it was W R Grace Perm-a-barrier at the time.

[Bill Robinson]

There are several building products that can be used that are not identified in the building code, that is technically speaking.

[OneWorld]

Thanks for the feedback guys. We have had wicking problems with Tyvek in the past if significant water got to it. Thanks for the Grace products lead - I will give them a call.

BTW: Aren't we all homeowners? I am an architect. I turned to this forum to talk to building pros who have more real world experience than product salespeople. I appreciate very much the technical feedback - not so much the request to justify my background.

Thanks again everybody.

Ken

[Mark Parlee]

Ken
This is a pro sight that we are somewhat protective of due to past problems.

On this section Bill keeps it tighter than on the building science portion of this site. We do get some homeowners that have had good questions and we all learned in the discussion that followed.

If you read the signup and posting regs you will find it is this way and Bill does a good job of protecting his/our territory and we do back him up on it.

You as a building design professional are welcome here and I am sure you can teach us a thing or two as well as learn a little as well.

Welcome to the forums; I hope you will continues to visit and participate.

if you need more information pleas do not hesitate to contact me by direct email or phone.
Contact info at my TBC website.

[Bill Robinson]

Thanks for the feedback guys. We have had wicking problems with Tyvek in the past if significant water got to it. Thanks for the Grace products lead - I will give them a call.

BTW: Aren't we all homeowners? I am an architect. I turned to this forum to talk to building pros who have more real world experience than product salespeople. I appreciate very much the technical feedback - not so much the request to justify my background.

Thanks again everybody.

Ken

Thanks Mark,

Interesting Ken, you even are asked some qualifying questions to get a membership at Costco, so why so protective of your background?



If your contractor had asked the question my response would have been different.

In addition to the stated posting recommendations one of my concerns is that most homeowners, post questions here and never, and I mean never give anything back.


FYI, persons making their living in the construction biz are not required to own homes to post on this site.