Togue and groove pressure treated lumber

[Jeffrey Mohr]

Ihave an old house from 1892 and am restoring the porch. The porch is severely deteriated. I am waiting for someone to fall thru it. The orgional slats run perpendicular to the house. They are tongue and grove and are 72" x 3 1/8" x 5/4 fir boards. Has anyone had sucess routing a tongue and grove on pressure treated lumber and jioning them all together. Warpage? Any recommendations?

[Steve Schlumpf]

Just moved this over from another forum and thought you folks could help Jeffrey out. Don't know if he still has a need for the info but the subject makes for a great conversation!

[Joe Petersen]

Don't know about tongue and groove, but some hidden fastener systems use grooves to mount. Eb-ty. (http://www.ebty.com/)

[Randal Stevenson]

A few years ago, I considered this, as well as replacing the boards with the typical tongue and groove boards. What I discovered, was all the predone tonque and groove boards I found locally, were junk (and there was a shortage that year on top of it), and the pressure treated stuff is real wet. I would be concerned with more cuppage/warpage/twisting with the pressure treated.

[John Wiedmeyer]

I have used pressure treated wood to repair old porch floors. The trick is to find the right boards. You need to find 5/4 decking that is vertical grained and has a tight ring spacing. It is not easy to find, but the bundles at the home centers sometimes have a few boards in them.
Next you need to dry it down to as low as you can get it. I try to get mine down to about ten percent before milling the tongue and grove. Seal the end that is exposed to the weather. I soak about four inches of the end with Smith's CPES to avoid checking. Next, back prime the bottom and edges using an oil base floor paint. Install the board, sand flush as needed, and apply one coat oil floor paint to the top side. As the board weathers, it will cup a little bit. I've found the cupping is less than the commonly used fir porch flooring. After a month or so, sand the board smooth and apply two coats of oil floor paint.

[Bruce Wrenn]

Here locally we have a pressure treatment plant. They used to treat T&G for me, but now stock it. Already been stacked and dried. Only way to go. The difference in price between SYP and pressure treated is less than the cost of deck paint. "Cox "sells it in lots of places.

[Jim Becker]

The one concern with PT for this application is that it's generally quite wet and will shrink significantly as that moisture is released. If you can get dried PT T&G as Bruce talks about, that would be preferable to milling your own.