If it’s worth building, it is worth building ‘to last,’ so here are three tips for working with pressure treated lumber.
Avoid Drying Out Your Boards
When you get your pressure treated lumber you’ll notice it is heavier than regular lumber. The exact moisture content varies, but pressure treated lumber has a high moisture content because it was recently submerged in the liquid preservative.
Unfortunately, this means that if your boards are allowed to dry out before they are nailed to a house or a deck, they will often end up significantly warped, bowed, and twisted.
To avoid the headaches caused by trying to install warped decking, most professional deck builders try to order their pressure treated lumber very close to when they need to use it. Once a board is nailed into a structure, it simply cannot warp or twist as much as it can if it’s laying around loose.
If you have to pre-order your pressure treated lumber you can still take some steps to slow down the drying-out process (to minimize warping). Simply stack the boards tightly together. That way their own weight can help pin them down and keep them straighter. And a tight stack restricts air circulation, slowing the drying process. Some people also cover the stacked lumber with a tarp, to further slow the drying process.
Handle With Caution
Pressure treated lumber is not ‘super dangerous” stuff, but it’s good to have a healthy distrust of chemicals and to take a few common sense precautions. These usually include wearing gloves, and not inhaling sawdust. Some people wear a dust mask. Some people sweep up sawdust from pressure treated lumber and deposit it into the trash. It’s always best to read and follow the precautions suggested by the manufacturer
Seal Up the Cut Ends
The pressure treatment process forces a chemical preservative into outer layers of the wood. When you cut off part of a piece of treated lumber, you’ll be able to see the darker band of chemical saturation—and you’ll see the newly exposed portion of the lighter, untreated ‘core’ wood.
In order to protect that newly exposed part, buy a quart of the ‘End Cut Solution’ NAME and apply it with a paintbrush. (Follow the manufacturer’s safety precautions, such as wearing disposable gloves.) Some people put on two or three coats for added protection. This helps seal and preserve the cut portion—but it’s never as good as the “factory application” because only the factory can use pressure to force the solution deep into the wood.
For that reason, the “factory end” should—if you have a choice—always be the end in contact with the ground or concrete. This is an especially good trick to remember when setting porch posts. Putting the factory ends down will help ensure your posts last as long as possible.