TYPAR Flashing in lieu of PT wood plate?

[Ben29]

I'm pretty sure there is nothing in the code that says you can use TYPAR Flashing Flex Roll in lieu of a 2x PT plate. But if there is, please tell me. Because I have a guy who built a 4,311 SF house on CMU piers without a 2x PT plate and now he needs a structural certification saying its OKAY.

 

[jayrod12]

Doesn't there need to be a connection between the two?

But to the original question, around here we also accept felt or poly wrapping of untreated lumber when in contact with concrete. I don't know if I personally consider Typar in the same league as those options, but it does prevent direct contact between the wood and concrete.

 

[XR250]

Not sure of the answer but I go into crawlspaces all the time where no barrier or connection was used and rarely see an issue.

 

[hokie66]

Your guy can't even align the piers and bearers. He doesn't deserve a certification.

 

[dhengr]

Come on, Hokie, they are in the same crawl space, what do you want/expect?

 

[BAretired]

@Ben29,

Apart from the TYPAR issue, would you be prepared to certify that installation?

BA

 

[Ron]

No, Typar is not a substitute for PT. Code does not recognize that as an application. Check the Typar Evaluation Report for applications.

 

[Ben29]

I guess I should just give the guy his money back and tell him to find someone else to certify it. I'm not sure what else I can do. I can tell them to prop up the girders and have them chisel out the top of the masonry pier and then slide a 2x treated plate in there? There are 36 piers!

 

[XR250]

What about jacking and replacing with sheet metal?

 

[Ben29]

XR250 - I like that idea. I was wondering if that would be an acceptable option. I considered how Simpson offers the column caps for GFCMU and concrete piers. Is sheet metal listed as an approved moisture barrier? Is there a list of approved moisture barriers somewhere?

The image below is from NCMA. See how they call out, "pressure treated sill OR use moisture barrier" What is an acceptable moisture barrier?

https://ncma.org/resource/concrete-masonry-foundation-wall-details/

 

[phamENG]

Depending on your climate, EPDM roofing material may be a better choice. I've seen aluminum termite shields that were not properly installed build up condensation and saturate the bearing edge of a wood member.

By the way - if you're in an area with subterranean termites, make sure you address that portion of the code in your certification - even if it's just a "there's no termite shield, ensure a suitable termite control method is employed per R318.1."

A moisture barrier is essentially a non-permeable material. Metals, rubber, heavy plastic (I believe you want <0.1 perm to call it a moisture barrier, where 0.1-10 perm is a vapor barrier - somebody wiser in the ways of building science is welcome to correct me there).

 

[dauwerda]

Take a look at section 317.1 of the IRC.

https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning#IRC2021P1_Pt03_Ch03_SecR317

The way I read it, you technically would not need PT for any supports on the interior of the crawlspace (assuming you meet ground clearance requirements, which it looks like you do). And you would only need it for the exterior if it is less than 8" above the ground.

 

[Ben29]

@dauwerda, I think this prevents us from having to use PT wood for the actual floor construction (i.e., the wood and joist themselves do not need to be PT because they meet the clearance).

 

[Ben29]

@pharmENG - thank you for the bit about the termites. I will be sure to include that verbiage in my letter. And thank you for the clarity on moisture barriers.

 

[dauwerda]

I do agree with that Ben29, but it also does not require PT in your situation. If it was required, this is where it would be. The code does not require the use of PT wood (or an impervious moisture barrier) in the situation pictured.

 

[phamENG]

I agree with dauwerda on his code interpretation, but I don't agree with the code. This can be a regional thing. Here in the mid-Atlantic, our crawl spaces can get very wet and humid. I'm not a fan of leaving untreated wood in contact with masonry in this area in any part of the building and for any reason. Ben's in PA - could be eastern or western - so it's up to him to consider the local environmental implications. Considering the fact that the inspector has questioned it makes me think it's worth a look. Could be the inspector is just used to seeing it, but it could be a local requirement.

 

[Ben29]

This house is in Maryland, FWIW. And actually, the inspector did not review the first floor framing at all, so that is why they are requiring a PE to certify the first floor, along with some other areas.

 

[phamENG]

Oh. It's one of those. Unless you've worked with this guy for a long time and this is a 'one-off' mistake (unlikely), I'd say thanks but no thanks.

 

[XR250]

Here is a pic from a recent crawlspace adventure. Previous high moisture levels and a pretty good point load here..

The house is 40 years old and did not have a vapor barrier for most of that time. That being said, I was in a few others this week with similar construction and age with no distress. This is in humid, central NC.