OK, well regardless of the request at hand it was an excuse for me to build something out of wood, so I thought why not. The steps which were requested were based on what she could have purchased for > $200 from an online retailer. The product is called a 3-Step Animals Matter Companion Stairs. Based on the dimensions provided (Three-Step: 30"L x 21"W x 21"H.) I could figure out how to build a set. Now I wasn't about to provide the nice soft cover this company offers, but I certainly could fashion a set of decent looking portable stairs for well...a dog.
For the construction of the stairs I used 3/4" Baltic Birch Plywood. I was able to cut all the pieces from a 4' x8' sheet with plenty left to spare. Back calculating from the overall dimensions I was able to determine the rise and run dimension for each step.
Since the overall height is to be 21" this means each step needs to be 7" high. The depth (or length) of the steps is 30" so this means the top or run of each step needs to be 10".
So my first step was to cut the boards required to make the rise and run of each step. The treads need to be 10" wide and 21" long while the risers need to be 7" wide by 21" long. I needed to cut 3 boards of each type for a total of 6 21" long boards. To cut the 7" and 10" widths I just rip cut them on my table saw. I then cut them all to length (21") using my chop saw. At the same time I cut a bunch of stringers which would provide support between the two sides. These stringers (6 of them) were were cut to 19-1/2" long by about 4" wide. The width is not critical as it just provides a structural support frame between the two sides.
The two sides (21" high by 30" long) were the most difficult part to cut. I debated if I should cut it our of a solid piece of plywood or build it by joining several 10" pieces of board. Overall I think that 3 10" wide pieces of length 20-1/4", 13-1/4", and 6-1/4" and just butt join them together would have been simpler, I didn't have a plate joiner at the time (which would have made this easy) so I decided to just cut the panel out of a 21" x 30" sheet. I laid out the lines of the sheet, drilled the corners and used a sabre saw to cut the pattern. The edges needed a bit cleaned up and straightened so I used my flush trim bit in a router against a straight edge guide to square everything up. Once I had one cut I just made an exact copy for the other side.
I started the assembly by first attaching the bottom stringers and one top string to hold the two sides square. I used #10-2-1/2" wood screws (counter sunk) to fasten the stringers to the side panels. Once I had the overall two sides up and square I attached the other stringers.
Once all strings (6) were attached and the glue at the joints had dried, I began attaching the riser and treads from the bottom to the top. A couple of #10 screws at each end holds them in place. I continued this until the entire stair case was covered. I finished assembly by sanding all edges and checking to make sure the steps were square throughout.
To finish the steps I putted all counter sunk holes (dozens of them) and sanded them flush with the surface. Then I lightly caulked some of the seams which looked like they might be problems. Once everything was sanded to about 1 120-150 grit, I put a round over on all the edges to give it a kind of finished look which will also be easier to paint. Final sanding was with 220 grit paper and then lightly with steel wool. I washed, cleaned the steps and primed with latex primer. Final painting was about 2 coats of "Simply Tan" latex paint. A few days to completely dry and it was done.