View Full Version : Drying Time for Pressure Treated Pine Decking?

Mike Peace
05-09-2007, 11:44 AM
I bought some 5/4 by 6" pressure treated pine decking boards to make a porch swing. It's very wet, straight from the Borg. I would appreciate anyone's input.

- How long do I need to wait before I can start using it on my project? I am most concerned about the 4 ft slats that I will be ripping 5/8 by 1" that I do not want to get all warped.
- If it needs to dry, should I dry it in my basement shop or outside?
- Plans are to use polyurethane finish.

Greg Cole
05-09-2007, 12:02 PM
Do not let it dry if you want it to stay flat & straight, thats what the fasteners are for.
Also the poly finish is not something that will hold up outside.



Cliff Rohrabacher
05-09-2007, 12:51 PM
Wet wood wants to check when it drys. It will dry faster if you cut it up but you will have some challenges keeping it from splitting.

Then when you think it's dry - it really won't be. You'll apply paint and it may sheet off in some months when the moisture causes the wood to move under the paint.

I'd wait to apply conventional paint some very long time maybe a year or so depending on exposure. Leaving the finished product in the sun will dry it much faster.

There are paints you can apply that will actually work with the moisture in the wood like 2 part urethanes and DURON has some urethane (one part) that uses moisture to cure.

I am finishing up a set of 9 reclining Adirondack chairs made from PT. I bought a whole bundle in the factory steel strap so the innards were swimming in free water.

I am planning on coating it with a deep penetrating 2 component catalyzing urethane tinted bright white.

I got the bundle home, broke it up, and stickered & stacked the whole thing placing fans to blow air through the stack. I cut the wood wet. There was not really any choice.

To control the drying (and you must control the drying) I wrapped poly stretch film over the ends of the pieces of wood. Each phase of cutting up lumber for the chairs say: seat slats, back slats, sides, etc., I'd sticker the pieces and wrap the ends so the moisture loss wouldn't cause massive checking.

Some pieces checked anyway. I drilled the check injected Titebond III with a large industrial syringe and a Yale 15G flat end needle and clamped 'em. End of check.

You Gotta seal the ends while the wood is drying or you will have massive splits.

On drying. I started these chairs by making my first run model. From that I built my plans. I used some PT decking that had been laying in shop for about 6 months.
It was still rather damp inside. I am unsure that it'd have taken paint well.

Lee Schierer
05-09-2007, 1:37 PM
I used PT lumber for the fascia boards around my grage doors. The previous ones had rotted. I had the boards home for about 1-2 weeks befor I cut them and put them in place. I waited about 3 m onths beofre I painted them. They were on the east side of the house and saw full morning sun. I didn't see any checking and the paint has been on them for over 5 years without any bubbling or peeling.

On your swing, you may encounter problems with any film type of finish you apply due to moisture absorption in areas where the finish does not completely seal the wood. Over lapped areas and joints will tend to suck in moisture from the rain and those areas will tend to peel or blister first when the sun comes out and the moisture tries to leave the wood through the heated surface. I gave up trying to paint the skirt boards on my deck for this very reason.

Kurt Forbes
05-09-2007, 1:41 PM
Are you certain you want to have your family sit on pressure treated wood?
That stuff is pretty toxic. A splinter in the rear would be a bad thing. you would be better off using some decent rot resistant wood or untreated wood and a water sealer.

Mike Peace
05-10-2007, 10:35 AM
I appreciate the input. Sounds like I will have more challenges drying and finishing than I thought.