When my daughter went to grad school, she wanted to travel light, so she decided that her bed would consist of a futon and a set of Ikea roll-up slats. Though, as her principal mover, I appreciated the idea of travelling light, I also thought her bed was bit too minimal - I wanted it at least to be raised off the floor. and I thought that without a basic frame the slats would shift and move. So I came up with a simple design that could be built cheaply and with a very minimal set of tools, transported easily, and assembled with very little effort, yet still creates a raised platform for a futon bed. The result has served her very well (she's moved once, and will possibly move again in another year). The total cost for this project was $40 - $50 ($30 for a set of twin bed slats from Ikea, and $10 to $20 for a couple of 2x4s and 2 pieces of 1/2 x 3/4 inch trim, a handful of small nails, 4 wood screws and 4 bolts). For tools, you'll need nothing more than a tape measure, a hammer, a marker, a hand saw (needed only to cut the wood to length), a hand drill, and 1/8" and 3/8" drill bits, and a screwdriver.
Step 1: Choose Your Bed Size and Gather Your Supplies
The first thing you need to do is decide what size bed you want. My daughter settled for a twin size and selected the Luroy slats from Ikea (Luroy Slats from Ikea). We bought the slats first, then unrolled them and measured both the width and the unrolled and length (with the slats pulled taught) so I could have the frame pieces cut to the right lengths. To build a simple frame for this set of slats, you'll need two 2x4s that run the length of the slats (mine ended up being 75-1/4") and two 2x4s to span the width (37-3/4" + 2" to allow for the trim). I opted for two 10-foot 2x4s and had them cut to length at the lumber yard, to avoid having to drag them into my shop. You'll also need two pieces of 1/2 x 3/4 trim to fasten along the edge of the 2x4s to help hold the slats in place. I bought two 8-foot pieces and had them cut to length as well. Most lumber yards will make one cut per board for free, so this saves you having to even use a saw for this project. In addition to the lumber, you'll need four 3/8 inch by 2-1/2" bolts, four 1-1/2" #10 wood screws, and a small package of 1-1/2 inch brads.
Step 2: Nail the Trim Pieces in Place
Once the pieces are cut you need to fasten the trim pieces along the edges of each of the long 2x4s, as shown in the photo above. I also ran a bead of glue along the bottom of each strip to provide extra holding power, but it's not necessary. I used trim nails and drove them flush so they would not catch on the mattress and tear it. a nail every 10 or so inches is more than sufficient. Notice that the trim is held back about 1/4" from the edge of the 2x4, because the 2x4s I used have a rounded edge.
Step 3: Fasten the Slats to the Rails
Once the trim pieces have been fastened to the rails, you need to drill and fasten the slats before you can assemble the rails to the cross pieces. Place the rails (the long 2x4s) on the floor and unroll the slats onto the rails, positioning them between the trim pieces, aligning the end slats with either end of the rails. Once they are positioned properly, drill an 1/8 inch pilot hole through the end of each of the end slats (bot don't drill into the 2x4s), and fasten the slats in place with the 1-1/2 inch wood screws.
Step 4: Position, Drill and Fasten the Rails to the Cross Pieces
The final assembly step is to position the cross pieces under the rails so you can drill the 3/8 inch holes for the bolts that hold the rails in place on the cross pieces. The only trick in positioning the cross pieces is to make sure that they are between the slats, so the bolts don't interfere with the slats. I positioned them about 1/4 of the way in from each end, then adjusted the position so they fell exactly between two slats, as you can see in the photo above. before drilling the holes, place a scrap of wood under the cross piece to protect the floor in case you happen to drill all the way through. Then use a 3/8 drill bit to drill the holes for the bolts, as shown in the photo above. As you drill each hole, drop the bolt into place (you might have tap it a bit, and if it's too snug then work the drill bit around a bit to produce a loose fit. The bolts don't need to be fastened or even tight, since their only function is to hold the rails in place on the cross pieces.
Step 5: Mark the Pieces for Easy Re-Assembly
The frame is now ready for the futon mattress, but before you put your bed to use I highly recommend numbering all of the pieces with a permanent marker as I did. This makes it much easier to re-assemble your bed after moving it, since the holes might not all be perfectly aligned if you happen to move the pieces around relative to one another. The other thing my daughter did was to put some adhesive floor pads on the rails to hold the rails slightly off the floor and protect the floor from scuffing.