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Lots of plywood at Home Depot have the letters RTD in the title, with no further detail. Many of these have multiple user questions of the form "What does RTD mean?" Answers seem to be split 50/50 between what it actually means though. On the one hand are those who think RTD stands for the manufacturing process. Almost all of these answers (and others on the internet) seem suspiciously close to this wording on theplywood.com which makes me suspect that a single source from 2017 has been repeated over and over on the internet enough times that it's being accepted as infallible.

Example:

RTD refers to the method used to manufacture the plywood. This is, essentially, next generation CDX plywood which is manufactured with a quality control system using RTDs (Resistance Temperature Detectors) to maintain correct temperature during the bonding process. This process helps ensure complete bonding of the layers to minimize delamination.

On the other hand are those who think RTD just means it's "rated," here's an example:

RTD is an abbreviation for RaTeD. Yes in the manufacture of plywood the use of Resistance Temperature Detectors is normal to ensure delamination does not occur later on. But this generally applies to all plywood manufacturing, not just to those listed as RTD.

So which is it?

brentonstrine
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The “RTD” in RTD plywood stands for Resistance Temperature Detector.

You have your normal CDX plywood for exterior sheathing. This plywood is made to function better outdoors - deals with temp changes and moisture better than other forms of plywood. The main difference between this and your normal plywood is that you will have less delamination.

Now RTD takes the CDX a step further and has controls for the amount of glue used, types of glue, and most importantly making sure the bonding temperature is highly accurate for each layer of veneer.

This will result in less delamination for CDX and makes it superior for outdoor use.

The grading difference between the two most common types of plywood can be summed up in that CDX is Exposure 1 rated (which means that water hitting it won't hurt it) and RDT is purely Exterior rated (yes I know CDX is still used as exterior sheathing in some places). Being exterior rated means it will withstand constant exposure to temp changes and moisture.

Depending on the price difference we may buy CDX for subfloors but RDT is used for everything on exterior, including walls and roof.

DMoore
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This might give you an appreciation for the difference:

Below is a basic old fashioned plywood press machine, the kind that has been in use since plywood was invented. Stack a bunch of layers of veneer on top of each other, some with glue between them, ever so often no glue, which differentiates the individual sheets. Then you press them together with a 400 ton hydraulic press and wait for the glue to set. You know an AVERAGE amount of time it takes under pressure, but to make SURE, you add more time just in case. enter image description here

In a more modern system, the glued and unglued veneer sheets are fed in between plates of steel before being pressed by the hydraulic rams. enter image description here

Those plates have small tubes carrying steam though them to heat the product as it is being pressed and buried in those plates are RTDs, Resistance Thermal Detectors, that tell the computer exactly how hot the plywood got. This way the computer KNOWS when the glue is set, so it eliminates the guess work and cuts the cycle time to make each batch. It's a more expensive process, but results in a more consistent product quality and a higher production volume, resulting in more economies of scale and thereby, lower costs.

JRaef
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But to confuse things even more, there are devices used to measure temperature in demanding applications that are called Resistance Temperature Detectors, or RTDs. These devices see a lot of use in space applications, where they have been used since the early days of the space program in the 1960's.

Goodrich Aerospace is one of the manufacturers of such devices.

Not anything to do with plywood .

SteveSh
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