So we've had this very sturdy but extremely plain looking concrete porch in the back of the house, and we've always wanted to make it warmer and more inviting. The obvious solution, to us, was to replace it with a wooden one. Wood is by far warmer and better looking than concrete, and if you maintain it properly it can easily last a couple of decades before you need to start replacing a piece here or there. On the downside, obviously, is the commitment to maintain it regularly. And by regularly, I mean a thorough cleaning and restaining (or repainting) once every two or three years.
Replacing the concrete deck with wood could have been done in one of two ways: completely demolish the concrete porch and build a 100% wooden one in its place, or use the concrete as a base and just add wood on top of it. Since our concrete was in good condition and would offer a solid base we decided to keep it and just cover it all with wood.
Building a wooden deck this way does offer the advantage of not needing to worry about digging foundations, putting in joists, etc, but you do have to worry about the proper slope of the concrete porch, allowing for good water drainage, ensuring any parts that would be subjected to possible water pooling are treated against it, and such. I've done my best to protect against those things and take notes/photos of them, but I'm sure there's always room for improvement. If you're going to build something like this, remember this really important rule: an extra ten minutes spent putting in better water protection at this point will save you from headaches, lots of hours and $$$ in replacement materials down the road.
Step 1: Materials, tools, etc
The material should be pretty obvious - wood. And plenty of it. When you go buy your supplies, make sure you get at least 10-15% extra of everything, because some beams will have unsightly knots, will not be perfectly straight (even straight ones might warp a bit in the sun if left unused for a few days), etc. Same thing applies to screws - get a lot of them.
This one comes before anything else. I've gotten dust in my eyes more times than I care to count, and have felt my ears ringing more than once after drilling and cutting. I don't want to deal with that any more, and want to avoid any damage. You should be very concerned with this as well, so make sure you use a good pair of goggles that seal the space between the lenses and your skin, as well as good ear plugs. Do yourself a favor and get a pair that can be easily removed and put back on (like the pair in the photo) even if your hands are dirty, as you'll need to do this often.
Depending on where you live and what is available, you'll probably have a choice between treated yellow pine (the green stuff) and cedar. The latter is naturally water and bug resistant, smells awesome and looks great as-is. The former is three to four times cheaper. You do the math.
Treated pine can always be stained and painted any color you like, but make sure you follow the stain/paint instructions carefully. I'm staining our deck, and the instructions I found were that you basically cannot apply any stain for several months because the chemicals injected into the wood will not let the stain penetrate too deeply and this means it won't last long. I'm going to let the wood weather until next summer, at which point I'll apply wood brightener/cleaner to it and then the stain.
You also have the choice of going with composite decking materials which look like wood but are made of much more weather resistant materials. These will cost you even more than cedar but will last way longer. Their down side, though, is that they really don't feel like wood (in my opinion). You don't get the same feeling of warmth, the slight creaking, the color, etc.
Quantities - this one will depend strictly on what design you choose for the flooring, the railing and any extras like storage under the deck, benches, etc. I've used the most common sizes of available lumber, though:
2" x 2" and 1" x 2" - floor support, railing balusters
5/4" x 6" x 10' - floor boards, railing top caps
2" x 6" x 10' - skirts
4" x 4" - railing posts
2" x 4" - top and bottom railings
Screws and bolts
There are a whole bunch of screws you can use on lumber, but you must absolutely ensure the ones you get are meant for use with decking (i.e. weather and [if using treated wood] ACQ resistant). The chemicals in treated wood will interact with non ACQ-approved screws and cause them to corrode (due to high levels of copper in the preservative), so you want to avoid that.
Sizes - most of the screws I used were 2" long, as that would go through the boards and offer a good amount of catch onto the base beneath them. For the handrails I used 2" screws (and nails) for the balusters and 3" screws to attach the railings to the 4" x 4" posts.
You'll also need concrete screws (e.g. Tapcon) for attaching the floor supports to the concrete. I used 3" screws for this step.
Finally, for the railing posts, you'll need 0.5" x 6" (for notched posts) and 0.5" x 7" bolts (for non notched posts) to attach the railings to the sides of the porch. The concrete in my case is 6" thick, which is enough room to attach to bolts one on top of the other, about 2" apart. If yours is any thinner I'd suggest looking for alternatives.
I used 4" nails to attach the balusters to the railings (along with the 2" screws). Same rules applies as for the screws - get ACQ approved (perhaps even galvanized would work) nails.
I used a fair amount of construction adhesive for places like the floor support, the skirts and the balusters, so you'll need several tubes of it. I also used carpenters glue when gluing the supports for the benches, but could have used the construction adhesive there as well.
Anywhere the water has a chance of accumulating near wood should get extra attention, and the first place this happens is on the concrete next to the runners. The wood is already treated against water, but since these places will be inaccessible in the future you want to do as much as possible now to prevent water damage later on.
Treated wood is basically wood into which a preservative liquid has been inserted by using a vacuum and lots of pressure. It's important to note, though, that this preservative does not make it all the way to the core of the lumber, and only infuses the first inch or so on all sids. This is just fine if you'll be using the lumber as-is, but you won't. You'll be making a ton of cuts to fit the wood into different sizes and shapes, and will be exposing the untreated innards to the elements. To protect these areas against moisture and bugs you'll need to treat them with a wood sealer, which is basically a liquid that smells a bit like paint thinner. It is transparent and does not leave a trace (you'll see it for the first couple of days but nothing afterwards), and can just be brushed on to the freshly cut ends. Keep this stuff nearby as you'll be using it often.
I most certainly don't envy people who had to build stuff before the advent of power tools. Even with the following ones you'll still need a bit of strength for some of the steps.
A regular drill and a hammer drill - You'll be needing two drills throughout the whole process because the vast majority of the holes will have to pre-drilled before putting screws in them. You'll also be needing a hammer drill for the sections where screwing into the concrete are concerned, so I had a regular drill with a screw head on it, and the hammer drill with either the masonry bit or wood bit on it depending on what step I was on. You don't need the drill to hammer when drilling pilot holes in wood, so a hammer drill that can turn the hammering action off is preferable.
Saws - you'll need a regular handsaw (for finishing cuts), circular saw, miter saw and a reciprocating saw. The last one is optional, though. I thought it would be a help in trimming the posts to their final height but could have just done it with a circular and hand saw.
Usual toolbox of stuff - hammer, screwdrivers, level, chisel, etc.
You'll also need wood drill bits, as all screws should be going into pilot holes instead of into raw wood. Using pilot holes on everything will certainly take you longer, but will avoid cracking and reduce the stress on the wood helping it last longer.