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· I have gas!
2,447 Posts
Discussion Starter · #1 ·
I went to HD looking for CDX plywood but they didn't have it. In the spot where they usually stack CDX, they had RTD plywood. It was Exposure 1, SYP (Southern Yellow Pine) but I have no idea what RTD stands for. Anyone know?

· the Musigician
10,405 Posts
found this.....

Exposure durability classifications are assigned on the basis of raw material composition and
adhesive bond durability. Panels are typically produced to one of two classifications: Exterior or
Exposure 1.
Exterior panels are designed for applications subject to permanent exposure to weather or moisture.
They are fully waterproof. Exposure 1 panels are suitable for uses that are not permanently exposed
to the weather, but where panels must resist effects of moisture due to construction delays, high
humidity, or other conditions of similar severity. Exposure 1 panels have a fully waterproof bond and
are made with the same exterior adhesives used in Exterior-rated panels. However, building products
distributors and builders are cautioned to store panels on skids off the ground and to tarp the unit
when there is potential of heavy rain or snow.
In the case of plywood, Exterior-rated panels are manufactured with C-C and better grade veneers,
while Exposure 1 panels are classed as "Interior with exterior glue" panels because they can be
constructed with veneer of D grade and better.

anything that touches the ground or sits on outside concrete has to be made for "ground contact".
different PT chemicals, and REALLY heavy as it's pretty much soaking wet.....


· Custom Cabinet Maker
1,097 Posts
Mouse! C D X C face, D face X exterior glue :}:}

RTD? Ready to take a dump??????????? :laughing:

Seriously tho, from what I read and searched for it seems that RTD is a process used to make the plywood. It supposedly improves the glue bond between layers thru better control of the heat and steam needed, therefore less delamination in use. At least that is what I brought away from reading.

· Civil Engineer
5,832 Posts
An RTD is a resistance temperature detector. It is essentially a thermocouple, designed to provide real time, very accurate temperature readings. RTD plywood appears to be exposure grade 1 plywood manufactured using RTD technology to control the temperature of the glue during application and curing. Presumably this makes the plywood superior to CDX plywood, which by the way stands for C face on one side, D face on the other side, exposure grade 1.

CDX is NOT exterior grade plywood. Exterior grade plywood uses superior glues to CDX. Since CDX is exposure grade 1, it is suitable for use as a substrate in damp environments, such as sheathing for roofing, or underlayment for tile. RTD plywood appears to refer to the manufacturing process; the only way to know the exposure class on RTD plywood would be to check the rating on the sheet, it should be stamped on the sheet.

· Registered User
11,730 Posts
I agree with Daniel on the rtd, as anytime I found it mentioned was to plywood manufacturing. Though all my research has shown APA uses the same glue in Exterior and Exposure 1 grades, only the bond durability has changed from the application. Also, 1/2" CDX is not warranted by the manufacturer for underlayment for tile, only as roof or wall sheathing, because of the knot holes and other voids. But now I'm nit-picking. Be safe, G

· Registered
1 Posts
I bought some of thaRTD at HD and "Ready to Delaminate" seems most accurate. Several 4 X 4 pieces I had stored in a covered protected outdoor area warped badly and started to delaminate after a rain. They did not get wet, only exposed to high humidity. Some scraps I left out in the actual rain completly came apart !! I am not impressed with this stuff. Guess thats why its cheap at 13+ $ a sheet.
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