Advantech T&G 3/4" sub floor

[Dave Zellers]

Anybody familiar with it? We're building a 3 season porch. The underside will be exposed to the elements 8' off the ground.

Is it built to withstand this over many decades or is it better to go with traditional CDX plywood? Just to be clear, after construction, it will never get wet but it will be exposed to high humidity every summer.

[julian abram]

It's great stuff. I had 3/4" AdvanTech down as a subfloor last summer that was exposed to rainy weather for 2 weeks. It remained flat, no warping/buckling or problems whatsoever. One corner of the floor was a little lower, so water collected and stood on it a couple days, water had no effect on it. It will darken in color a little after water dries off. Much better product than the old plywood days. It think it's impossible for water to penetrate it because of the all the resin that holds it together. I would use PL adhesive and screws or ring shanked nails to install it.

[Dave Zellers]

Thanks- it does sound like a good product.

[Randy Red Bemont]

I used it as the sub-floor for my house. It can take the rain when building and will make a great sub-floor for your porch. I will use it again on my next house and workshop in a year or two.

Red

[Neil Gaskin]

What type of flooring will you be putting over the subfloor? What type of windows will be sealing it off and I assume you will have the bottom of the floor framing closed off with a soffit material of some sort?

If it truly will never get wet either CDX or Advantech Will perform equally well. The Advantech Will handle getting wet and moisture in the short term better than CDX plywood from my experience. Either will cause problems albeit slightly different with long-term exposure to moisture.

[Bradley Gray]

Given the low quality of CDX these days I would vote for Advantech.

[Dave Zellers]

I assume you will have the bottom of the floor framing closed off with a soffit material of some sort?

This is EXACTLY the point! No- I am not planning on closing that off. After completion it will never get wet but it WILL be exposed to humidity, every year.

[Sam Murdoch]

Well I've never heard of it being used exactly in this way but it certainly has been used as a sub floor over a lot of crawl spaces and/or over otherwise damp environments. 8' off the ground with lots of air circulating and a dry top surface - I would not hesitate to use it that way. I might consider - just as a precaution, though I am confident that it is not needed - to apply a coat or two of a good exterior paint. It has a waxy finish on the top side but I think the underside could take a finish. Anyway - more a precaution and a visual clean up than a necessity.

[Dave Zellers]

Just to put a period on this thread for all who may come across it via search--

I just couldn't shake my concerns about using this in this application, given that if it DID fail years down the road, it would be disastrous to have the sub floor disintegrate. So yesterday I emailed Advantech and today I received this response:

Dave,

Thank you for your inquiry about AdvanTech. AdvanTech is a highly water resistant wood structural panel that is design to resist moisture related issues during the construction cycle; however, AdvanTech is still an exposure 1 rated product and is not designed to replace marine or pressure treated wood products. When used in recommended applications AdvanTech is highest rated wood structural panel on the market; however, for this application we do not have test data or field testing to show that the AdvanTech panels would be suitable alternative this application. We would recommend using marine or pressure treated wood panels.

Please contact us with further questions or concerns.


Given that both termites and carpenter ants are a problem here, I have decided to use Pressure Treated plywood as the subfloor.

[julian abram]

Just to put a period on this thread for all who may come across it via search--

I just couldn't shake my concerns about using this in this application, given that if it DID fail years down the road, it would be disastrous to have the sub floor disintegrate. So yesterday I emailed Advantech and today I received this response:

Dave,

Thank you for your inquiry about AdvanTech. AdvanTech is a highly water resistant wood structural panel that is design to resist moisture related issues during the construction cycle; however, AdvanTech is still an exposure 1 rated product and is not designed to replace marine or pressure treated wood products. When used in recommended applications AdvanTech is highest rated wood structural panel on the market; however, for this application we do not have test data or field testing to show that the AdvanTech panels would be suitable alternative this application. We would recommend using marine or pressure treated wood panels.

Please contact us with further questions or concerns.


Given that both termites and carpenter ants are a problem here, I have decided to use Pressure Treated plywood as the subfloor.

Well, you got the answer straight from the horse's mouth, think you came to the right decision. Your application is kind of special so no sense in gambling on a material that might not perform in the years ahead.