Hi,
I have a question about using Pressure Treated lumber that is still fairly wet, to build frame-work for a deck. What do you need to do, or worry about, when you don’t have the luxury for the lumber to dry-out before using it. I know that it is going to shrink, but what techniques, or preventive measures, can be done while framing to prevent any problems later?
From building boxes and fitting face frames to installing doors and drawers, these techniques could be used for lots of cabinet projects.
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
You need to order it and have it delivered as soon as possible, they spread it out in the yard to dry. In the summer it dries pretty quickly, so even a day or two helps especially if it is held up off the ground on scraps of 2x4 so the air can circulate.
Conversely, if you are using PT deck boards, don't have them delivered until the day you need them, then lay them tight against each other and they will develop nice gaps as they dry.
I'm sorry, I thought you wanted it done the right way.
And when u look out on the lawn and it looks like u spilled a giant bag of pretzels u'll know its dry.
Ok. And your point is ... ?I'm sorry, I thought you wanted it done the right way.
heard thattyke
Just another day in paradise
I got your point . . . and you're right.
I got his point too, sort of. So what do you have for an alternate? Structural steel? If you're going to use PT lumber because it is rot and bug resistant, and because it is structurall yappropriate, then you have to learn to work with its shortcomings.
I'm sorry, I thought you wanted it done the right way.
I think he was making a funny point that drying PT before use is a little more precise than throwing it out in the yard. If you aren't in the mood for pretzels, it really pays to spend a little more time drying it out. I saw his humor, apparently some others didn't.Seriously, why is PT so dang wet? Would it take that long to dry it again after treatment? I think it is ridiculous to buy a product you can't use for several days. A common scenario: HO buys a fence full of 8 foot 4 x 4's, takes hours placing them precisely in a straight line, nails on his stringers and pickets, steps back, admires his perfect job with pride, and receives proper marital rewards. Three weeks later, the top of the fencerow looks as straight as Richard Simmons. Gone is the pride; but, thank goodness, the wife can't take back her prize.
I have had too many projects go to crap becuase of twisting PT....I won't use it except for what I thought it was intended for, contact with or near to the ground or concrete.
If I just use good quality 2X, Paint ,stain or seal it properly. It will last 30 years easy. May not be the Lifetime of PT but close enough for me. The next owner will rip it out and change it...just like I did. The PT was a damn mess.
You can certainly try to use KDAT (Kiln Dried After Treatment). You won't get the twisting and warping, and the wood is dry. On the other hand, it's also about twice as much $$, and isn't available everywhere....actually, it's hardly available anywhere in Ohio.
Or, you could sticker your wood in a shaded and dry location for a few weeks & it should air out & dry nicely, without getting nasty on you.
My daughter is building a deck. Based on what I read here, I told her to buy the lumber, sticker it in her garage & let it sit for three weeks. She noticed a big difference at one week, & a really significant difference after the 4th. It was nice & light, but started to bend, but most of the shrinkage was gone & it wasn't anywhere near as messy to work with.DonThe GlassMasterworks - If it scratches, I etch it!
That's exactly what I'm saying. KDAT, to my knowledge, is not available in my area. It makes sense to me that air drying, under more controlled conditions than my garage, would produce a significantly better product at very little more cost. This would increase PT sales and customer smiles. I also use PT only for ground contact and where codes insist. I would use it more if it were a better product.
I had a similar situation a couple of years ago. Made a small trellis over a patio next to our garage using PT 1x4's. Wasn't "informed" about the properties of the wet pieces and left them in the garage for a few weeks (more out of my own procrastination rather than foresite). Installed them when they were nice and dry, then cut one wrong and went back to get another one that was still green. Cut that one and put it up. Everything turned out nice and straight except for one piece. Guess which one it was?
Wood for treating is loaded on cars and run into the pressure chamber. As it comes out of the chamber, it is loaded for shipment and shipped---still dripping. It arrives at the lumberyard/HD/Lowes/Menards/etc. with the outer boards dry---and the inner boards dripping.IMHO, that was the major problem with CCA leaching arsenic into the soil/hand transfer---since the dry wood did much less of that. But, what do I know?I decided to stop taking life so seriously, it is, after all, only temporary.
Ed, IME the advisability of doing what you suggest with the decking boards …….depends. It depends upon how wet the wood is when it arrives, what the current weather conditions are when it arrives, how fast you can get it installed and the geographical location. It won't work well around these parts.If the wood is truly at the fiber saturation point when it arrives and you install it immediately as suggested (each board snugged up tight to its neighbor)…..then every time this deck wood returns to the fiber saturation point because of prolonged rainfall, those boards will be once again tight to one another and no individual board drainage can take place. Standing/ponding water results. I've seen guys take this approach with wet PT more than once and seen the end results of it. The one guy bought the lumber and laid the deck in the freezing temps of winter. You guessed it. That wood was indeed at or very near the FS point when he laid it because the wood froze on the transport truck and dried down very little in the three days it took him to screw it in place. That was about 12 years ago and that deck still ponds water today if it rains for three days straight. He grumbles about it every time.If a guy presumes the wood is at the FS point but it really isn't, then the end result of laying them tight could be even worse. I've seen this, too. When the wood reaches the FS point at some time in the future…..the swelling wood of floor has the potential to buckle if the fastening system isn't secure enough to prevent that. If it is well secured, then the boards would hopefully just compression set against one another……. avoiding the buckling,,,,,,but still would cause ponding water. When PT comes out of the treatment chamber, it is usually at the FS point. This doesn't mean you can assume it's still at the FS point when it arrives at your site and when you install just because it feels heavy and wet. The only real way to know if the wood is at the FS point is by knowing the FS point for the species in question and then using a meter on it.I will agree that your approach would probably work fine if the location doesn't ever receive enough prolonged rainfall to return that wood to the FS point….or "maybe" if the HO is truly diligent about keeping a viable coating of water repellent on the wood at all times. Very few HOs really do that.
Knowledge is power, but only if applied in a timely fashion.
Edited 7/29/2005 12:04 pm ET by GOLDHILLER
Good points. Down here the average humidity is under 50%, usually around 40%. Most of the PT lumber is wet enough that water squeezes out when you run screws into it. After one season of south Texas summer sun, I can't imagine the boards would ever soak up enough moisture to approiach how they left the plant. Don't forget that the treating process uses pressure to force the preservative into the pores of the wood.
I'm sorry, I thought you wanted it done the right way.
Just use it as it is, it's a deck. It's going to shrink, swell, crack and check for the rest of it's life. Nailing it up will at least keep it from turning into pretzels.
Beat it to fit / Paint it to match