When I visited my sister in 2008, she said having a small deck above the entrance porch would be nice. So having a look at the situation, there was room for a deck bout 7' by 8', and I figured I'd be able to build one in about a day. So I took on the challenge and built the deck...
The roof above the porch consisted of a slightly slanted roof, covered with "roll on roofing". I didn't want the deck to be at the same slant as the roof. I also didn't want it too high above the roof. So I used 2x4's, which I tapered towards the higher edge of the roof against the house.
In the picture at left, I put one of the decking planks against the brick to make sure I'd cut the joists to all come to the same height.
I fit the joists to the roof by marking a line a fixed distance from the roof with a pencil, while the 2x4 was propped at the other end to the right height plus the height of the offset I used with a pencil. The roof was sufficiently level that the lines were straight enough that I could cut them with a circular saw.
On the low side, there was already some pads on the roof from the previous railing that was there, though these needed some repairs. The pads are Basically a piece of pressure treated wood on top of the roof, with roof cement smeared around the edge, and a piece of shingle on top. This should keep water from flowing to where the load is applied, so hopefully there should be no leakage brought about by where the deck rests. Although on the end nearest the house, I just rested the 2x4 joists on top of an extra shingle I put on the roof. With them fitted to the roof, I figured they should apply pressure evenly and not cause a puncture.
Next was to put the decking on. I used 5/4" decking, which, with the usual actual dimension being a fair bit smaller than the specified 'nominal' dimension. The actual dimension was 1" thick.
I didn't want to have to rip the last board to make it fit, so I screwed down the first and last board, and then figured out how much space I had left. The space between the two boards at right is the total gap that I had to work with, and I spread the boards out evenly so all the gaps were about the same size. I first split the gaps into two gaps of equal size on opposite sides, and then screwed down the middle board, so that I only had to space out half the boards at once by eyeballing it.
I did want gaps between the boards, to allow some airing so that it can dry out after a rain.
To make the railings, I spaced the spindles evenly across the width of the railing, so that I didn't end up with an odd interval at the end. Of course, this meant that the actual spindle spacing worked out to some awkward number. I always use a calculator and a tape measure for this sort of thing. I use the calculator to work out the position of each spindle, and mark that with the tape measure. Even when working on a project that is all in inches, it's best to do this in metric, because at least metric is in decimal.
And screwing the railings together. I did this on the floor. It would have been better to have a pair of sawhorses to do this on to avoid having to bend over so much. But I didn't have any sawhorses handy, and there really would not have been room on the small deck anyway.
Each screw has one screw at the top, and two on the bottom. I used two screws on on end so that the whole ladder arrangement would have more rigidity to it, especially against being shifted side to side. Without corner posts anchored into something, it's the rails internal rigidity, and the fact that the rails are attached together at a corner is what keeps the whole thing standing upright and rigid.
One of the railings mounted. To attach it to the wall, I screwed the last 'spindle' into the brick with tapcon screws. Except I used a 2x4 instead of a 2x2 for the last spindle to give it extra strength.
You can also see a batch of spindles that I just cut to length towards the left. I needed shorter spindles than they had, plus I wanted the top end to be square, so I had to cut the end off all the spindles. I did this in batches by putting 10 spindles side by side and cutting them all at once.
This picture shows how the corner went together.
I really wanted the corner to be sturdy. The corner posts only rest on the surface of the deck, with a few screws driven in at a diagonal to hold them. This isn't strong enough to withstand the force of somebody leaning against the railing.
The railing is held up mainly by its own rigidity and how the corners are held together. So if the corners were to suddenly come apart, the whole railing, plus whoever might be leaning against it could suddenly come tumbling off the roof.
So the corners have lots of screws holding them together. The photo at left shows the corner assembly almost done. I neglected to take a photo of the finished corner before I attached the board on top for the railing.
The illustration at left shows how the corner is screwed together. The two upright 2x4's that make up sort of a corner post also help hold the horizontal 2x4's together.
Finally, I put some horizontal boards on top of the railings. this makes the railing a nice wide surface to put things like coffee cups on. Unfortunately, it also makes the railing a tempting place to sit, which is not such a good idea, considering how far down it is to the ground.
This shot shows better how the railing is attached to the wall. The upright 2x4 takes the place of the last spindle, and is screwed into the brick using five 3.5" long tapcon screws.
And here's my 18 month old nephew. He's got a thing for brooms, and as soon as he saw me sweeping up, he wanted the broom. His sweeping technique still needs a bit of work though.
And finally, the deck, as seen from below. With the trees up against it, it's actually a very cool and private space to hang out and watch the street from. I wish I had something like that on my own house!