Tips for building a deck

1. Never assume that any existing structure is square or level, always check existing structures for square and level and use screws, not nails, for fastening.

2. Ensure the back plate of the deck (the board that goes against the house wall) is perfectly level before you permanently fasten it. This will make leveling the entire deck much easier.

3. Mount the two side boards to the back plate and level. Hold side boards in level position using pieces of wood to brace it up.

4. Mount front board onto the two side pieces. Check level across the front of the deck. As long as your back plate and sides were installed level, the front board should be level. If it's not level, you'll have to go back and check the sides and back plates and make adjustments accordingly.

5. Now it's time to square up the frame. Using the 3,4,5 rule is the best way to square up your deck. Measure 3' down the side board, from the front corner, and make a pencil mark on the outside edge of the board. Now make a mark 4' from the front corner along the front, on the outside edge of the board. Now measure from pencil mark to pencil mark and if your deck is square the measurement between the two marks will be exactly 5'. Make adjustments by moving the deck frame from side to side until you get 5' between both pencil marks. Double check both corners before continuing.

6. Now double up all the boards of the outside frame from the inside. This will give you a 2 ply ring joist for the outside frame of the deck * when using 3" screws, make sure to put them in on an angle, so that you don't put the screw through the other side.

7. Now you're ready to install the joists in your deck. Joist should be run at 16" on center. Pick a corner to start from and make a pencil mark on the front and back plate at 15 3/4" from the outside edge. Now mark an "X" on the side of your mark, opposite to the side you measures from (ex. If you started from the right corner, mark the "X" on the left side of the 15 3/4" pencil mark. Your joist will be installed on the "X" side of the pencil mark. From the 15 3/4" mark, make marks every 16" along the front and back plates, and mark and "X"  on the same side of the marks as previous.

 8. Once all your joists are in, it's time to install the joist hangers. Make sure to use nails that are rated for joist hangers.

9. If your joist are 8' long or longer, you'll have to install a row of solid bridging along the center of the deck.  Make a mark on each side of the deck at the center point and use a chalk like to snap a line across all the joists. Make square lines down from your chalk line to ensure bridging goes in square. Stager the bridging from one side of the line to the other, to make it easier to fasten the bridging to the joists. The measurement for the bridging on 16 o/c is 14 7/16".

 10. Your now ready to install your deck boards. When installing the deck boards, make sure the seams are tight. A lot of people space the boards, which is a good thing, but when wood is left out in the elements it will shrink, so if you keep the boards tight, they will shrink to create a gap. If you space them you could end up with a much larger gap than you would like.

Sean Cunningham