Bunk beds are a great way to save floor space in a small living space. If you have three children you may consider using a triple bunk bed to save space. You may go with a more traditional bunk bed or look at alternative ways to save space.
Determine the height that you want your bed to be. You should allow at least 36 inches between bunks. You can lower the overall height of the bunk bed by placing the bottom bunk directly on the floor. Cut your corner pieces to that height. Mark where you want each frame to attach to the corner posts. Sand all of your wood smooth with an electric sander.
Measure your mattress size and cut your boards for the frames to that size. Cut the slats, 3 for each frame. Screw the boards together in the frame placing the 2 smaller boards within the outer boards.
Screw slats along the bottom of each frame. Each frame should have at least 3 slats evenly spaced along each bed frame.
Use carriage bolts to attach each frame to the 4 corner posts at the determined marks.
Add steps to the outside of the frames with wood cut to the same length as the width between the two posts. Use screws to hold firmly in place.
Stain or paint the pieces of the bed.
Allow to dry and put the mattresses in place.
To create more head room you may want to have the middle bunk jut out from the bed at a 90 degree angle from the other 2. If you do this you will need additional 2 additional corner posts for the middle and shorter corner posts for the head of the middle bunk. You will build the bed the same with the middle bed frame coming out and attaching to the shorter corner posts on the bed. Another option to save headroom is install a trundle bed underneath a normal bunk bed. The trundle would roll under the bed during the day to save room. This prevents the bed from being as high up. You may want to paint or stain your wood pieces before you begin assembling them. This is especially true if you plan on assembling the bed in the bedroom. Carriage bolts will allow you to detach the bed frames and makes moving the bed much easier.