We (my dad and I, with some hammering slavery by LG) built a deck in our (mine and LG's) backyard over the 4th of July weekend (1997). It was a 4.5-day struggle, but we are (all) quite pleased with the result. For all the gory details, read on.
We built the deck on existing concrete, two adjoining slabs of different sizes, each of which sloped in two different directions (both away from the house, and both away from each other). We also extended it by a couple of feet more away from the house. As a final complication, we needed to stay under the threshold of the door that leads onto the patio, so at the high point of the slabs we had only about 11/16" of space for substructure; this sloped away to a maximum of just under 3 1/2" at the low point.
Support posts and general layout...
After an extended morning trip to the lumberyard, we got to work on the five support posts for the extended portion of the deck. We dug down 18" with posthole diggers, put in round concrete forms, stuck in the 4x4 posts, and poured in concrete, all the while keeping everything level, plumb, and aligned. Things went smoothly. Even the digging was a little easier than we anticipated: less clay than I've encountered elsewhere in my yard.
In the time that remained, we did some general layout of the deck. Stakes and strings all over the place. A line-level is a nifty and quite indispensable tool for this sort of work.
Substructure...
We used shot nails and concrete screws to attach the substructure to the slabs. The bigger slab was very hard concrete with lots of rocks, and neither the drilling (holes for the screws) or the shooting worked very well alone. After lots of trial and error, we got pretty good results by drilling a pilot hole, then using a shot nail to finish the job. Even this didn't always work great: sometimes the nail wouldn't hold well, and other times it would go in so deep that the nail gun's driver would hyperextend itself and get stuck in the hole.
Because attaching to the slab was such a pain, we wanted to minimize it, so we decided to go (on the slabs) with joists 24" on center, and then put braces in between them every 16" as nailers for the deck boards. The braces could be nailed in from their ends. For the off-slab part of the deck, we used a more standard substructure, with 2x8 joists about 20" on center.
For the on-slab portion of the deck, we ended up with 10 long joists (perpendicular to the house) and 74 braces. This was by far the most time-consuming and difficult part of the job. We had to measure, cut, and fit (and often, re-cut) every single one of these boards. We first cut each one to length and then cut along a straight sloped line lengthwise. We did all this with a circular saw. I'm getting to be quite the whiz with a circular saw now.
Decking...
We used 5/4" rounded deck boards for the deck surface. LG and I had been thinking that having the boards at an angle other than 0 or 90 degrees (relative to the house) would look better. Perhaps 45 degrees, or maybe perpendicular to the angled side of the deck.
When it came time to get to it, I noticed that we had (accidentally) ended up with one of the long joists pretty close to the middle of the deck. I wondered how it would look to have the boards meet at an angle along that joist. At first I was still thinking that (half of them) would be perpendicular to the angled side, which would have meant they'd meet at a 60-degree angle in the middle. This would mean a lot of waste, though, both in materials and in work time. So we tried out having the boards set at 45-degree angles, so they'd meet at the middle at 90 degrees. We liked it, so off we went.
Much of the substructure, especially the part in the middle, near where the two concrete slabs meet, was too thin for the 2-1/4" deck nails we used. As a result, we had to custom-cut many dozens of deck nails. The best tool we had to do this was a pair of side-cutters, which will do the job all right, but only with quite a heavy squeeze. By the end of Monday morning, I hoped that I would never have to cut another deck nail for the rest of my life.
We used 1/4" spacer boards to keep the deck boards evenly spaced as we laid and nailed them in place. Since they met at 90 degrees in the middle, it was straightforward to match them up there. At the other ends, we left them overhanging by enough that we could cut them off to the right length later.
We placed the first two boards to meet more or less at a random point along the middle joist, and started going relative to that point. We didn't really consider what might happen when we got to various corners, edges, and obstacles elsewhere on the deck. But we got lucky time and again that the spacing worked out just right. For example, at the corner nearest to the kitchen door, we ended up with just the right amount of space to use a deck board without ripping it narrower to fit; the same thing happened in the inside corner near the living room door.
The final step was to cut off the ends of the overhanging deck boards. We marked them with chalk lines, then I cut them off in one (well, several) fell swoop(s) with the circular saw. (Remember what I said about being a whiz?)
Railings, pergola, benches, etc....
Ahead in the plans are railings, a step down into the back yard, and a built-in bench or two. We had hoped to get to these this summer, and have talked quite a bit about the design, but the likelihood of the work occurring is diminishing rapidly (as I write this on 11 August). Even farther ahead will be a pergola or some other roof-like structure.