There’s different materials that you can use to build a deck. We’ll be building this deck out of pressure treated lumber. Pressure treated lumber has got preservatives forced into it to protect it from termites and rot. Now it comes in green or brown. The green kind of weathers to a grayish color over a couple of years.
But before we get into all those details, let’s first take a look at the deck we’re going to be building here and some of the structural elements supporting it. The deck is going to be sixteen feet across and will come out twelve feet from the back of the house. The supporting system is made up of joist. On a simple deck the joists usually run perpendicular to the side of the house in to the deck boards. The outside joists are called a perimeter joist, or rim joist. Joists are supported by posts.
One common configuration is to reinforce the rim joist that runs across the end of the deck and then put posts underneath it. There are a couple of names for this arrangement: Flesh Header, or Beamless Deck, or an Upbeam.
The configuration that we’re going to use has a beam that runs under the joist. With this design the end of the deck cantilevers out past the beam. You can also set the post in a little from the sides of the deck as we’ll be doing. Your posts have to rest on solid footings in the soil. Now the minimum depth of the footing varies from region to region, so it’s really important to find out what’s required in your area. Our footings will be solid concrete. They start 42” below the ground and they’ll rise to about 4” above the ground.
A variation for the footing that’s also popular is to have a concrete pad below the frost line and then run the post down into the ground to rest on it. Now where the joist meets the house they’re supported by a piece of lumber called a ledger board. And once you’ve worked out your design installing the ledger board is usually the first construction step in building a deck.
After removing some of our vinyl siding, we mark the location of our ledger board on the sheeting. We need to make sure to take into account any rim joist that will butt into the house next to the ends of the ledger board. To prepare our ledger board the first thing we do is to cut it to length. Always wear safety glasses when using a circular saw, and we tend to wear particle masks when sawing pressure treated lumber.
Our next job is figuring out where do we install the joist hangers that support the ends of the joists? We’re going to double up our side rim joists. These get special hangers that we don’t have to worry about now. The rest of the joists, the field joists, will be spaced 16” on center from the outer rim joist. These joists will be held in place with joist hangers and we want to attach the hangers to the ledger board before we install it. So I measure out 16” from the end and mark for our first regular field joist. I also put an “X” to show which side of the mark the joist will go on. Now I can mark all the rest of the joists. The tape measure has special marks for each multiple of 16” so it was pretty easy.