Purchase the 2 common boards, making sure to get the 1 x 3 x 8 size. If your hardware store will make cuts for you (our Home Depot does this for a small fee), ask them to cut the boards into the following sizes: — 4 boards at 17 inches (the rungs) — 2 boards at 5 feet (the sides)
Set up the saw horses outside. Sand all sides of the boards using an orbital sander. You can use a sanding brick if you don’t have an electronic sander but it will just take a little longer.
Remove the dust with a rag or tack cloth. This is important to make sure there is no debris on any of the wood as you assemble and prep for staining.
Now it’s time to measure and mark the position for each ladder rung.
The first ladder rung (17-inch board) will be placed 3 inches from the top of the 5-foot boards. Measure and mark each 5-foot board accordingly.
The spacing in between each rung will be 12-inches. So, from that top rung, measure 12-inches below (or 15-inches from the top of the 5-foot board) and mark the placement for the second rung. Do this again for the third and fourth rung. Be sure to keep 12-inches between each rung (17-inch board).
Apply a small amount of Gorilla glue on the sides of the rungs (17-inch boards) and place in between the ladder sides. You want the rung boards to be angled so that the opposite corners are flush with the opposite side of the 5-foot blanket ladder sides.Look closely at the pictures and you will see what I mean for this position. They will look diagonal on the side boards. This position will give you more leverage for when you’re drilling in the screws to keep the rungs secure.
Carefully use a drill and 2 screws on each side to screw the rung boards onto the ladder sides.
Repeat the steps until all rung boards are attached with screws and glue.
Wipe off any excess glue.
Mix your stain and use a brush to apply it evenly to the ladder, one board at a time. Wipe each side of the board with a rag after you brush on the stain and move to the the next board.
Touch up the ends of the boards with stain, wipe and let dry overnight.