of Home Improvements
*Framing your Deck*
Set the Rim Joists
On this particular deck we chose to set and square our rim joists as our next step. We cut the rim joist to length and leveled the frame using temporary 2x4 supports. We then squared off the frame using the old 3 4 5 method.
Set the Girder
Now that our frame was level and square we were ready to set our posts and install the main support girder.
We hung a nice tight string line where the girder was to be. Since we were using 2x8's we measured down from the string to the footing bracket and then subtracted the width of the 2x8 to get the length of the 4x4 post.
We then installed post brackets on both the top of the post and onto the top of the footing. The main girder was then assembled by attaching two 2x8's together.
To give us some working room we used longer temporary supports to raise the frame of the deck. We inserted the girder into the top brackets of the posts and secured it with 1 nail driven into the post. We used 1 nail so that we could easily remove it for a final adjustment if needed. With some extra help we moved the girder into position and carefully removed the temporary supports.
Now that we had
the frame resting on the footings, we again checked the frame for level
and square. When we were happy that our frame was perfect we attached
the post brackets permanently.
Set the Ticos
It was now time to set the ticos on the ledger board. Since we were using 5/4" cedar on a 45-degree angle as the decking material, we set the ticos at 12" on center intervals.
The span and spacing vary widely. It is always good to consult your local building dept if you are not sure of the local requirements.
Here are some general guidelines that you can go by.
Span refers to the distance between support points beneath a joist or a beam. Spacing denotes the gap between parallel joists, studs, rafters and the like.
Span ratings depend on the species and grade of lumber you select, as well as its size. Builders and lumberyards have span tables you can consult to find out what size your joists need to be to span a given distance.
For example, you can use a treated pine 2-by-6 joist to span up to 10 feet, while a 2-by-10 joist of the same type can span up to 16 feet.
The thickness and composition of the decking material also affects joist spacing. Cedar, redwood and pressure-treated pine or fir are the solid woods most often used as decking.
Decking sold as 2-by lumber-actually only 1 1/2 inch thick-can be installed over joists spaced 24 inches apart on center. Decking designated 5/4 inch, which is actually only 1 inch thick, requires joists spaced 16 inches apart on center.
Most synthetic or composite decking materials also require joists spaced 16 inches on center, though some manufactured boards require 12-inch on-center spacing. It's best to check with your supplier about spacing and span ratings. (See article on composite decking)
Set the Joists
After all of the ticos are secured in place and you have marked the front rim joist, measure the distance between the ledger board and rim joist. The measurement should be the same for each joist. If it is not, check for any bowing of the rim joists and also make sure that the frame is still perfectly level and square.
After you are sure that the frame is good you can cut your joists to size. Most boards have a slight "crown" to them. To check for crowning, hold one end of the board about a foot from your nose with the other end resting on the ground. With the wide side up, sight down an edge of the board. If there is any crown, your eye will easily see the edge as being slightly curved.
When you install your joists, place all the joists with the crown up. In so doing, you'll get a more consistent floor surface. Each board should be toe nailed to the main girder and the outside rim joist. Some areas might require ticos instead of just nails.
Installing the Decking
It is very important
that the first board be installed perfectly. We used a large speed to
make sure that the first board was at a perfect 45-degree angle.
All decking boards should extend past the rim joists to accommodate any trim you may plan to use.