I had been thinking about buying a harder mattress and bought one spontaneously one day. But I made a mistake in thinking that I had a full-sized bed, when in fact, my bed frame was a queen! This wasn’t a bad surprise as I didn’t like the bed frame I had, but it did push me towards a new bed. I could not find anything online that appealed to me so I decided that it would be easier to like something if I participated in making it myself.

IKEA items used:
  • Slats from an old IKEA bed
  • Foam and mattress cover from an old IKEA mattress
Other materials and tools:


  • Hammer

Full-sized Bed frame:

  • 4 pieces of poplar wood cut to size
  • 6 L shaped mounting braces
  • Spax brand screws 1.25 and .75 inches long (size 8)


  • 4 pieces of pine cut to size
  • Foam
  • Padding
  • Fabric
  • Nails
  • Staplers

Hack instructions for KALLAX full-sized bed:

Bed frame

1. Build all three IKEA KALLAX shelves and place them in a U shape in the room where you want the bed to be.

2. Although using the official measurements of the KALLAX shelves the distance between the two side shelves was supposed to be approx. 63 cm, I found it was 68 cm. At Home Depot, I bought two pieces of poplar wood with a width of approx. 6 inches and a length of 68 cm.

I then connected the two pieces of poplar to the two bookshelves in the U facing each other using the 4 bed rail fasteners which I bought on Amazon. I didn’t connect them at the top but a few cm down. They were very easy to install. To install them into the poplar, I used a screwdriver to screw them directly in.

To screw the rail fastener into the KALLAX shelves, I had to drill holes first. I’m not sure how big the drill bit was since I eyed it. The screws I used for this step were 1.25 inches long.

3. Next, I used two L-shaped ½ inch mounting braces (with three holes for screws on each side) to connect each of the side KALLAX shelves to the shelf at the base of the U. To do this I drilled holes into the KALLAX shelves with the drill first, and then screwed in nails (.75 inches long) with a screwdriver by hand. With this step, all the shelves were connected to each other.

4. Next, I attached the 4 ¾ inch mounting braces to the shelves that made up the sides of the U (2 on each side). Then I took two more pieces of poplar that I got at Home Depot (about 3 inches wide and 147 cm long (the length of one KALLAX bookshelf) and screwed them into the poplar pieces attached earlier with the screwdriver by hand, and to the mounting braces in the previous step. The purpose of these pieces is to support the slats.

5. I used 14 slats from an old IKEA bed. I had to cut them down by a few cm to make them 68 cm each. I used Velcro tape under each slat.

DIY Headboard

1. I purchased 4 pieces of pine. Accidentally I didn’t purchase the correct length/width and worked with what I got, but ideally, the width should be the size of the bed, which in my case is 147+16.5+16.5=180 cm. The height of the wood is a subjective preference. I chose to go with 4 pieces of wood arranged in rectangular shape instead of one piece of plywood for a number of personal reasons (I don’t really lean into my headboard so it’s firmness doesn’t matter to me and a large piece of plywood was harder to transport from Home Depot than pieces of wood).

2. I used nails and a hammer to attach the pine together.

3. I cut the foam away from an old IKEA mattress. Since I didn’t want to use glue to adhere the foam to the pine, I used an old curtain to support the foam by wrapping the foam with it and stapling the curtain to the back of the pine. I also used these old curtains to cover the legs of the headboard. I used the mattress cover from the old IKEA mattress to create the back cover for the headboard (using the staple gun) and bottom supports you see in the picture.

4. I bought the upholstery fabric from Joann’s. The first time I bought it I didn’t buy enough since it shrunk when I washed it So I had to return to the store and buy more. The minimum you should buy is 2 yards of fabric for a headboard for a full-sized bed, but it’s probably better to buy a few extra inches just in case.

5. I used the staple gun to attach the fabric. It’s easy to correct mistakes when stapling by using a flat tipped screwdriver to remove the staple.

6. I realized that the sides of the top of the headboard were too “sharp” so I added additional padding to them.

Finished headboard

Right now, the headboard is not attached to either the wall or the bed because it doesn’t feel necessary, but the legs of the headboard can easily be screwed into the KALLAX shelves and the back of the headboard can be secured to the wall using Velcro tape.

Cost for my full-sized bed:

The KALLAX shelves were $46 each, the wood for the bed about $15, the wood for the headboard about $18, the fabric $40 (not counting the fact that I had to buy it twice), and the screws about $5. I reused some materials (slats, foam, mattress cover) and had access to the drill, screwdriver and stapler gun so these were free. So total was about $300 (if you include the 4 additional storage boxes from IKEA).

If you know what you’re doing and get all the materials together in one go, you can complete this project in a day. It took me 3 weeks though from the time I bought the KALLAX shelves in IKEA to the final screw!

What was the hardest part about this hack?

It took me a while to figure out how to connect the KALLAX shelves securely. Since I’d never done anything similar before my imagination in this regard was limited. The online tutorials I came across were inspiring but they didn’t give me a good understanding of the best way to connect the shelves. It wasn’t until a friend suggested I connect the two shelves on the sides of the U with wood to secure them, that I had my first “aha” moment.

A random Amazon search then introduced me to the concept of bed rail fasteners which I had not known existed! It also took me time to realize which mounting braces I needed since I’d never used them before and didn’t know where on the shelves to put them.

The last “aha” surprise came when I realized it would be best to return to Home Depot and get more poplar on which to lay the slats … which was a much better way than the original idea I had. Oh and don’t try drilling screws into poplar wood. You’ll end up inhaling screw (lead) dust! It’s a soft wood, screw them in with your hand!

Finished full-sized bed:

~ by Lena Shuster

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This content was originally published here.