You’ll want to begin installing your deck frame at the sturdiest, most solid point on your deck. In the case that you’re mounting to your house, that point is where the deck begins to leave the house. Measure from one corner to the farthest corner of your outer post. (Optional: Depending on the lengths of lumber that you are dealing with, it may make more sense for you to add 3” to this measurement and have your outer frame extend 3” past the corner on this side. This connection will be explained later.)
Cut two pieces of 2×6 pretreated lumber to this length.
Clamp the two pieces of lumber together in two directions: (1) to keep the boards pressed together, and (2) to keep the sides of the boards flush with each other.
Use 2-1/2” exterior wood screws to attach the boards. A couple of screws every 2’ or so is plenty; you don’t need to go wild here.
In the instance that your outer deck frame abuts with a
Use a heavy duty kreg jig to drill four pocket holes into your doubled-up 2×6, two on each side at one end.
Have your 2-1/2” heavy duty pocket screws handy.
Prop the doubled-up 2x6s up so the tops of the lumber are flush with the connection lumber (in this case, the wall-mounted lumber). Use 2-1/2” heavy duty pocket screws to attach the boards.
Install pocket screws into all four pocket holes, two per side. The outside edges of your corner should now be flush.
Place a level on your doubled-up deck frame boards to see where it will attach to the corner post.
In the instance that you are attaching this doubled-up 2×6 to a bracketed 2×6
Don’t fear. Simply use a hammer and chisel to remove the portion of your deck frame that will go over top of the bolt heads.
Measure how far out the bolt heads and washers extend, and measure the size of the bracket rectangle itself, then chisel out that much.
Set a level on the doubled-up boards, and make sure it’s level as you align the floating end with the post.
Keeping the level and your doubled-up deck frame boards in place, predrill holes for your lag bolts (try to reach the drill bit into the corner post if you can). Drill out about 1/2” deep with a removal bit that is slightly bigger than your washers.
This will allow the bolt heads to go into the lumber, rather than stick out, which will help immensely when you go to install your exterior deck boards.
Use a ratchet drill bit to install your lag bolts WITH WASHERS. Don’t ever forget the washers on these. (These are 3/8” diameter 4” long lag bolts, which is long enough due to the countersinking.)
As you can see, the face of your deck frame is flush, with the lag bolts countersunk into the pretreated lumber.
Install a full lag bolt and washer to hold the board in place while you do the other lag bolt. Repeat the process for a second lag bolt. You can install a third and/or fourth if you’d like, but it’s not necessary.
Now that the two corners are installed, use the same lag bolt process for attaching the doubled-up deck frame to any center 4×4 posts.
Now that the first doubled-up deck frame perimeter piece is installed, you’ll use its end to begin your second section. This next section will be installed much like the first, with a few things to keep in mind.
When you measure this second stretch of outer deck framing, you’ll want to measure to a mountable point. In this case, it was halfway through our second pergola post. You may find yours to hit a 4×4 post; measure to the halfway point of this so that both ends can be attached.
Also, and this is very important, you’ll need to measure from the OUTER corner of your frame. In this case, now that we’ve added a doubled-up lumber frame, you’ll measure to the outside corner of these boards instead of the corner of the post. The corner of the post means nothing to you anymore, with relation to frame board length. (However, if you chose at the beginning to add 3” to your original board length and now have a 3” overhang of doubled-up deck framing, you’ll measure to the inside of these boards.)
Fortunately, the bracket of your pergola post only has to be dealt with on one side, so at least one of your deck frame installations won’t require chiseling. Hooray!
Begin the next section of deck frame install at the end point of the last section, which should be at the center of a deck frame post. Two lag bolts should provide plenty of support at each post, if you’ve done the research and spaced the boards out according to recommended spatial-weight ratios.
When you come to a point on your deck that doesn’t allow you to mount a bracket, neither does it allow you to install pocket screws onto both sides of your doubled-up framing boards, you might have to get creative.
In this instance, pocket holes were drilled on one side of the doubled-up boards as well as on the top.
A 6” corner bracket was then installed with #8 nails to add additional support.
While it’s not how a deck would be framed in the ideal world, you sometimes have to get creative when dealing with obstacles and retrofitting something in place. This setup will provide plenty of support in this little corner.
Note, again, how you must carefully consider which side of a corner can accommodate the additional 3” length of your boards. You can’t simply measure to the corner of the post on both sides, because that would leave you with a 3” blank square on the very outer corner of your deck.
In some instances, the lag screws must be installed from the post side out to the doubled-up deck frame. That happens when there’s a permanent obstacle on the outer edge that won’t allow access to that side of the deck frame. If this is the case, countersink about 1” into your 4×4 post so that a 4” lag screw will hit into the second (outer) 2×6 pretreated lumber of your deck frame.
Some sections of your deck frame might incorporate a variety of these deck framing methods, and that’s perfectly fine as long as each is installed with sufficient support in its own right.
At this point, following this routine procedure, you should have completed the outer perimeter of your deck frame.
It can’t be stressed enough, as you work on this, to check and double-check for level and flush at every point. Being precise and accurate at this stage of the game will not only make it easier for you as you begin working on the deck floor, but it will also make the end result turn out much better.
Depending on the size of your deck, though, you may need to add in a bit more framing for support. This deck will be 14’ by about 25’ at the longest point, so we will need two additional framing beams running across the deck. Note: Install these support beams in the same direction as you want your deck floor boards to run.
With your tape aligned on the sides of the posts that you will be using for these support boards, measure from the inside edges of your deck frame. Mark this length on two 2×6 pretreated lumber boards, and cut them one at a time. Stack the boards and give them a two-directional clamping all the way down the boards.
Once again, you’ll want to screw these boards together.
These beams will be in the center of your deck and, thus, will carry the bulk of your deck support responsibilities. 5” lag screws will be used for these.
Holding the doubled-up boards in place, flush against the two posts that they will be using for support, place a double 2×6 bracket against the wall-mounted framing board.
Mark the position of the bracket, including the inner sides and the top. Be sure that a helper is holding the other end of the beam flush and in line on the other side of your deck frame, so that your markings are accurate. Note that the bracket will NOT be installed flush with the top of the 2×6 frame; instead, it will be installed a little bit lower so that the beam it holds is flush.
Use #8 nails again to install the bracket, using your pencil marks as guidelines.
Place the beam into the bracket.
Pound in the additional nails into the beam lumber; there should be two diagonal nails into each of the 2x6s on your doubled-up beam.
Clamp the other end of your beam in place, keeping all edges flush and paying particular attention to the tops of your framing boards. These need to be evenly flat.
Install the other end of your post using the same steps for deck frame installation that you’ve used previously: predrill, drill countersinking hole, ratchet in lag screw and washer. Repeat.
Next, move onto mounting your beam to the middle post, since both ends are now firmly installed.
You’ll probably want to clamp the beam to the post while you’re predrilling and ratcheting in the lag screws. Even if it’s flush to begin with, the beam has a tendency to push away from the post as you’re screwing it in.
Repeat for the other center beams.
Congratulations! You’ve completed installing the main support beams for your deck.
Next will come joists, installed perpendicular to the beams.
But, for a minute, sit back and enjoy what you’ve created so far. It’s becoming a reality, and you’re getting things accomplished. Well done.