Expanding the back deck (part two)

back deck first day crossbeam joists

After getting started Friday on expanding the deck by installing the crossbeam and pre-cutting most of the joists, I started early Saturday morning placing and aligning the 8 new long joists that will form 3/4 of the expanded part of the deck. (The rest of the landing will be extended out again by 4 feet for the rest of the expansion.)

Wrangling the 2x8s into place was surprisingly easy with the big crossbeam there to lay one end down on, which allowed me to just stick one end of a 2×8 up in the air and rest it on the beam. Then I only had to lift up and hold the other end to get each aligned on the mark (spaced 16″ apart on center) and flush with the top of the ledger board for a level surface for the decking to come.

Since I don’t have a framing nailer and decided not to use this project as an excuse to buy one, I used 4 to 6 3″ deck screws in each joist to hold them in place temporarily until attaching the joist hangers later on. After just about two hours of work, I had all eight of the new 8′ joists in place.

back deck joists attached back deck joists attached

My plan all along has been to keep and use the existing structure of the landing. That adds some extra support for the entire thing with two additional 4x4s in concrete, the existing ledger board, and the overall frame around it that I was planning to connect shorter joists to.

So I ripped up the old decking off of the landing and then attached shorter 4′ joists to bridge the gap between the old landing and the crossbeam. To add some extra strength, I put carriage bolts in the rim joist and the band board on the old landing before attaching the shorter joists.

I also came up with a nifty solution to the “how in the world do I lift up this 16-foot 2×8 rim joist by myself and get it lined up with the joists and attached” problem.

I built two little holders that I attached to the joists out near the ends, so I could (similarly to the crossbeam for the joists themselves) stand the 2×8 up and lay it into the holder, and then lift up just one end and lay it into a holder on the other end. Then I could easily adjust the level on each end as needed before screwing it into place.

rim joist holder back deck

I also, of course, squared up the joists (measuring 90º in the corners) and marked the exact spot for each on the crossbeam before putting in the joist hangers. Then I screwed the joists into the crossbeam to hold them into place until attaching the hurricane ties on Sunday. By 4 in the afternoon, I had all the new joists, the rim joist and the band board in place and ready.

back deck all joists in landing

After ripping up the old decking, I could even move the 5/4 decking onto the deck and start dry fitting to measure and also have a place to walk and sit without fear of falling through.

back deck joists finished decking ready

This is where it got more complicated.

If you look in this picture above, you can probably see that the new joists to the left of the landing are higher than the existing joists to the right. I stupidly started building without checking the slope of the landing, which was sloped away from the house pretty significantly, and much more than the 3/8″ slope that is typical for some decks. (Water running toward the house on ours is less of an issue because of the fact that our deck doesn’t connect to joists or other wooden structure inside the house — the ledger is drilled into a concrete slab and waterproofed. I added some more sealant but this is getting more boring than this post was already so I’ll stop now…)

I laid the new joists to slope slightly away from the house, but at less of a slope than the old landing. So I had to find a way to get those joists to line up.

I ended up doing a mixture of just adding in new joists with less slope, sistering up new joists to old ones, and finally shimming two of the old joists where I couldn’t fit in or sister up new ones.

Here you can see two joists that were sistered up to the old, too-low joists. I added carriage bolts to ensure strength and stability. To the left of those, I actually ripped out two of the old joists and just replaced them with new ones. I couldn’t do that all the way across because of where the bolts were in the ledger board.

back deck uneven level out new joists carriage bolt sister

For the the two outermost joists that I could neither sister up or easily remove, I just ripped down a shim for to match the slope of the newly added joists.

back deck uneven level out new joists shim

With that problem solved, I then had to find a way to bridge the gap between the new joists, as the old rim joist was obviously lower than the rest. So I just ripped a short piece of decking that was the appropriate height already to lay between the joists.

back deck uneven level out new joists

All in all, this is what prevented me from being able to finish this project all in one weekend. I was burning daylight on Saturday night trying to finish these joists, and ultimately stopped because it was 8 p.m. and loud things like hammering in joist hangers would have to wait until Sunday.

But by early on Sunday morning after trip #2 to Home Depot for the extra bolts, hurricane ties and other supplies, I had the platform 100% ready for decking.

Coming next: installing the decking and railing and coming to grips with what was probably a hilariously comical deadline of finishing it all in one weekend.

back deck joists all finished ready for decking

—

The back deck expansion

Comments are closed.