For similarly easy shelving plans, see: http://www.instructables.com/id/Cheap-easy-low-waste-bookshelves/
For similarly easy dining table plans, see:http://www.instructables.com/id/Cheap-easy-low-waste-trestle-table/
As a professional carpenter, furniture maker, and designer/builder, I see a lot of home carpentry projects that are grossly overbuilt and over-engineered. One of the goals of this Instructable is to avoid the unnecessary overbuilding that I frequently see on this site, and that I see every day working in the residential construction industry. Many of the building methods we (in the US) use today are horribly wasteful despite the advances that have been made in materials science and structural engineering, because most people in the residential building industry, from architects and engineers to carpenters, are mired in tradition, doing things a certain way "because that is how it has always been done", rather than consulting the best available science, or even questioning their own assumptions about "the right way to do it". I don't intend to knock tradition, either. Many of the tricks, techniques, and tools that I use daily are definitely "old-school", but seem to have been forgotten.
This bed is designed to be cheap, lightweight, sturdy, and produce a minimum of waste, using a minimum number of tools. It is intended for use with a futon or mattress without a boxspring and provides storage space underneath sized to fit common cheap plastic storage bins. It also provides good ventilation for the futon or mattress, something that I learned was necessary after my expensive futon grew a large mold/mildew patch on the underside. For those who might think that this bed is flimsy, my wife and I use it nightly, and I am 6'-5" and weigh 240lbs. I wouldn't jump up and down in the middle of it, but it will easily take any other abuse you commit upon it. When I calc it out, this bed uses 23.16 board feet of lumber (1 bd.ft.= 144 cu.in.), or 1.93 cubic ft., and produces only 42 cubic inches of waste, about 1.25%.
Instructables member frazeeg has posted a SketchUp model here.
Step 1: Materials and Tools
(4) 14' 1x4 #3 and better pine
(1) 10' 1x4 #3&btr pine
(2) 10' 2x4 Std&btr fir larch
(8) 3" #10 wood screws
(66) 2" #10 wood screws
Try and pick fairly straight, pitch (sap) free lumber, if your local lumberyard lets you do so. Some yards are stingy about this. Try telling them that you are building a bed, and that you would rather not have pitch all over your mattress/futon and floor.
The finished dimensions of the top of the bed are 76" x 55". A queen mattress is 60" x 80". The slight mattress overhang covers up the ends of the slats and keeps the user from bumping their legs on them, and uses standard lumber lengths efficiently.
A note on screws: I am a professional carpenter and furniture maker, and I make things easier on myself by NEVER using Phillips head screws. The Phillips head was designed to "cam out" at a fairly low torque for assembly line work before the advent of adjustable torque limiting drill/drivers. I use only Robertson square drive or Torx head screws, and save myself a lot of time and frustration.
Saw (Skil, hand, jig, or miter. Shown is a Skil)
Square (Speed, framing, or try. Shown is a speedsquare)
Drill (Cordless or corded)
Appropriate driver bit for your screws
#10 pilot bit/countersink
Step 2: Measure, measure, mark, and cut.
Start by checking both ends of each board for square, and mark and trim square if necessary. Never assume that anything about a board is square.
From three of the 14' 1x4's cut nine pieces at 4'-7" each.
From the fourth 14' 1x4 cut one piece at 4'-7" and five pieces at 1'-9"
From the 10' 1x4 cut one piece at 4'-7" and three pieces at 1'-9"
From each 10' 2x4 cut one piece at 4'-0" and one piece at 5'-11"
Step 3: Predrill, countersink
Step 4: Assemble and square up frame
Step 5: Lay out and attach slats
1) Turn the frame over so that the cross brace is underneath.
2) Face a long side of the bed frame.
3) Holding the tape in your left hand, hook the end on the edge of the frame on your right.
4) With your right hand, make marks at the following lengths, and draw an X to the right of them.
5) Make the last mark at 71-1/2" and this time make the X to the left of the mark.
6) Repeat the process, but in mirror image, along the other long side of the frame.
Attach the slats using (4) 2" screws per slat. Place each slat over each X and align the slat edge with the layout line. Use a scrap of 1x4 to gauge the overhang as in the second photo. Note that the first and last slats will overhang the top and bottom of the frame be 1". Check the slats for bow, and put it up, so the weight of the futon pushes it flat later.
If you can't find the eleventh slat, it is still screwed to the bottom of the frame to keep it square. Taking it off now is O.K., because the screws through the slats will hold everything square.
Step 6: Build and attach legs
Turn the bed over, so that it is slats-down. Place a piece of 1x4 scrap in the inside corner of the 2x4 frame. Insert a leg, butting it to the 1x4, and attach it with (2) screws per 1x4, on the diagonal. Look at the photo. Remove the scrap, move it to the next corner, and repeat. The gap provided by the scrap helps to prevent squeaks.
Pay attention to the orientation of the legs, because in cross section one side is longer than the other. Structurally, it doesn't matter, but if you take the time to make a symmetrical layout, it will look better.