Deck

We've been working on a small building. It's 10' x 12', with a 6' covered deck. It could be a small cabin, or a sauna. It would be easier to build if it was close to the ground, but I want to be able to get underneath, and I want the floor height to match the yurt.

The gable roof overlaps the yurt roof enough to give a dry passageway.

2x8 beams at the perimeter, with 2x8 joists on joist hangers. Beams attached to the faces of posts. 

Beams attached to the sides of posts. It's stronger to notch posts, or to set beams on top of them. I wish I had put beams *under* the joists, as it's so much stronger. Then I probably could have dropped down to 2x6 joists and gotten a stronger floor. It might have made bracing simpler, too. 

When we built the yurt, digging the footing holes became this never-ending nightmare, and we wanted to avoid a repeat. I think I overcompensated. I aimed first for 6 posts, but according to span tables the beams wouldn't be strong enough for a 10' span. So we split that one with another post, giving spans of 5', 5', and 6'. The lumber we found wasn't as good as I had planned for, so I decided to add still more posts. We're now up to 11. *sigh*

Footings are pier blocks set a 4"-6" below grade. Frost depth here is minimal, so we just dug down far enough to find solid ground. Where it was deep, we added 3/4"-minus gravel, tamped, to come back up to the right height.

Lumber: 2x8 12', 2x8 16', 4x4 treated 10'.

The treated 4x4s were chopped up in to posts. Left them long, since we can cut them down later. Then we attached a beam to 2 posts, and set the height & level. 

My plumb bob hanger has a 2" offset.

Once we're plumb, added temporary bracing.

The first joist. Doubled. Through-bolted.

I don't advise you to copy this building method. Through-bolting is a little less secure than other methods of attaching to a post. Also, these bolts are near the end of the joist, where the wood is weaker. These bolts are 8" x 1/2" hot-dipped galvanized. 

I didn't have a long enough drill bit, so we clamped the joist in place, drilled through it, removed the joist, and finished the drilling. I picked a snug hole size, and used a sledgehammer to drive the bolts in, which knocked a few things out of alignment. I know that tight is stronger, but I think a slightly bigger hole would have been a good idea. I did eventually buy a long drill bit to use elsewhere.

The joist doesn't really need to be doubled. The main reason is that it will be under a wall, so it provides a little wider bearing surface for the wall, instead of supporting it on edge. I don't know if that's actually important, since the wall is pretty rigid already. Alternately, I suppose I could have put blocking between this joist and the next one, at the same spacing as the studs. *shrug*

To get everything square, I needed another joist and beam. But once the 2nd beam goes in, it would interfere with access to the yurt *and* would get in the way of removing the yurt steps. So we had to do a bunch of stuff in one day.

In preparation, I used a shorter stick as a temporary beam, to get things close to square. Then on the big day, we removed the steps:

No steps!

Then we removed the steps (they're really heavy!), swapped in the correct beam, squared everything, added the tall posts next to the yurt, installed joists in the deck area.

Nails ready for joists.

My carpenter friend said that joist hangers can be a pain to work with. He suggested we attach the joists to beams with nails first, then come back later and add the hangers.

Dylan installed this joist hanger himself.

Dylan is sure-footed. 

Here you can see our strategy for attaching beams to posts. I'm using a Simpson Strong-Tie Deck Joist Tie DJT14Z. These can work with either through-bolts or #10 structural screws; I'm using the screws.

Once the deck-area joists were installed, we placed 5/4 x 4" cedar decking. It's planed smooth and the edges are round. This will be nice under bare feet.

5/4 is slightly more than 1" (and will shrink more when dry). The 4" is of course 3.5". I have 12' to cover, and 41 * 3.5" = 143.5". So I bought 21 sticks, 12' long, cut in half, for a total of $90.

We didn't fasten the decking, except for the first 1 and a cleat after the last one. So we can walk on it but I don't have to commit yet. I still need to work under the deck, so I can just pick up the pieces in the way.

Finally, we hauled the steps in to their new home. They're not perfectly level, but they work.