Part 3: Understand rail and frame installation early.
Once we get past the sale of the decking and we get the decking on, it is equally important that a homeowner understands the importance of the rails and their installation. There are tons of rails available, made from materials ranging from PVC and wood plastic composites (WPC) to steel, aluminum and wood.
There’s a new building code in effect that took place in January that says that composite deck rails have to have a label attached to the exterior of the box to be code compliant. If it doesn’t have that label, deck installers can’t use them. That’s a building code rule. This change is particularly important to lumberyard owners. As a retailer, you don’t want to bring in a bunch of inventory and then not be able to sell it. Unfortunately, LBM dealers see that all too often. We see salespeople or manufacturers try to sell us decking or railing that is not code-approved and not well thought-out.
Before you get the decking, you have to put the frame up. Today we have a lot of choices in framing materials. There’s a difference between wet-treated lumber and KDAT kiln-dried treated lumber. KDAT treated lumber is like preshrunk jeans. It’s pre-shrunk in the treating process, and is pressurized with chemicals into big cylinders, and that makes the boards swell up and so they vary in size.
But over the first six to nine months, those boards are going to dry out and start to shrink back down. If you’ve got your decking on and they start to shrink, your decking will become undulated, it will start to telegraph and it will show by the joist underneath it that it has shrunk or moved. A lot of contractors recommend planing off the tops of joists to reduce any unevenness of the joists. All that is going to do is be a temporary fix that’s going to work for the first month, then they’ll start to shrink. Now those joists that you planed down are going to be shorter than all the rest and so you’re going to actually cause a bigger problem.
The right way to do it is to use a kiln dried treated lumber that’s kiln dried after it’s been treated (KDAT), or use steel framing. Steel is a very expensive choice, but that also provides a stable surface.