Introduction: Floating Shelves Using Box Section and Scaffold Planks

So I wanted to create a huge set of shelves for all our books and comics in the living room and wanted it to be part of the wall and editable if I really wanted.

I’ll explain all the processes but the sizing of it and spacing is going to all change depending on the size of your wall or where you’re going to put it.


Length of 100mm x 100mm 2mm wall box section
Strip of 100mm 3mm steel (optional)
3 standard scaffold boards
Clear varnish
Shims/ spacers/ scraps of thin wood for levelling
Stove wax/ metal sealer/ metal paint for sealing the metal from moisture
Rawl plugs (dependent on wall)
Screws (biggest you can use)

Angle grinder with cutting blades, flap discs and sanding pads (saves a lot of hand sanding)
Hand file
Welder (optional)
SDS drill (depending on the wall)
Centre punch
8mm HSS drill bit
8mm Masonry bit (depending on the wall)
Blow torch (optional)
Paint brush
Right angle

Step 1: Cutting Box Section to Length and Holes for Shelves

I decided to have the bottom of the box section 1m off the floor to leave space for our sofa and have the box section at 45° to make all the measuring and levelling easier but all the angles and sizes can change depending on how you would like to do it.

Using an angle grinder I cut 45°off of the end of the box section length. Using the distance from the ceiling to my 1m mark I used pythagorus’ theorem to work out the length of the box section, I then cut 45° cuts to make 2 pieces that length with both ends slanting the same way.

After working out the gaps I wanted to leave between each shelf and using pythagorus theorem again, I measured and marked pairs of 45° lines along the box section in the same direction as the cuts I had just done. Make sure to leave a 20-50mm gap from the bottom to support the bottom shelf. The lines should be exactly the width of your scaffold boards apart so that when they are sanded it is still a snug fit.

I measured and marked 70mm back on each side to match those lines and give my slot for the scaffold board.
Using an angle grinder again, I cut all the lines I had marked. I found when cutting the small side cuts, if you use a used small disc you can cut it without going out of your slot or leaving a nick in the finished cut.

All cuts then need to have the burrs removed using a hand file.

If you’ve never used an angle grinder before, wear ppe, don’t take the guard off your grinder and do a bunch of practise cuts to get used to using one.

Step 2: (Optional) Adding a Bottom Plate

I wanted to cap off the bottom to make the bottom stronger and make it look better but if you don’t have access to a welder then you could cap it using something else like a piece of wood hammered into the bottom or some cleverly bolted bent plate of metal.

Using an angle grinder, I cut a section of 100mm strip steel to fit and welded it onto the bottom of the box section

Then using a flap disc in an angle grinder, I cleaned up the weld and plate.

Step 3: Drilling Holes to Mount the Box Section to the Wall

To mount the box section to the wall i made holes in the back of the slots so I had access to them from the front and so they would be hidden once the scaffold was put in.

In the back of each slot, drill 2 holes about 50mm apart using an 8mm drill bit and then countersink the holes.

Step 4: Cleaning Up and Sealing the Metal

I wanted to get a brushed steel effect but it not be too shiny (big mistake)

I ended up having to hand sand everything to get all the sanding marks in the same direction but I saved myself some effort by doing the bulk with a sanding pad in an angle grinder.
Because I didn’t want it too bright or shiny, I heated the box section using a blow torch and added stove wax with a brush then wiped it off using a cloth.

The idea of this is to open the pores of the metal, evaporate all the moisture and replace it with the wax giving a dull sheen that won’t rust (hopefully)

I have a habit of using the most labour intensive method because I prefer the look... so save yourself some time and clear coat it or paint it with any metal finishing product you like.

Step 5: Fixing the Box Section to the Wall

The wall I was adding to was partially a timber and plasterboard wall and partially a rock chimney that they had plastered over. (my house is over 100 years old so it has some weird walls)

Where the chimney was, I knew I could drill in, add rawl plugs and screw in to that. The plasterboard wall, however, needed reinforcement.

I measured 200mm from the walls either side as the start point of each piece of box section. I then held each piece up to the ceiling with a level that showed the 45° on the side. I got someone else to roughly mark out where they were and where the slots were.

Once I knew where they would be and where the slots were, I knew where I needed to add reinforcement to the wall as that was where I was screwing in

I cut holes in the plasterboard, added horizontal bits of wood to the existing structure and then screwed the plasterboard back in. As you can see from the photo. I then went back and filled the gaps I had made and painted over it.

With some help, we held up the metal in exactly the position using the level again and marked where the holes were.
We drilled holes, as deep as our screws, in the chimney using an 8mm masonry bit and an SDS drill, we then added rawl plugs.
We held up the metal again, screwed the top and bottom holes of each piece of box section and double checked it was all correct. We did this by putting a long board across 2 corresponding slots and put a level on the board. After it all being okay, the other screws went in.

The final check was to hang off of each piece, that way I knew the box section could definitely withstand about 75-80kg each and I really didn’t need to worry about it falling down.

If you’re at all nervous about what your wall is made of or where your wiring is etc. I would recommend getting a professional in to do this bit as a burst pipe or a screw through a wire can be expensive.

Step 6: Putting in the Scaffold Boards and Levelling

Once the steel is up, you can arrange the scaffold boards however you like and cut them to size.

The photo shows a test of the shelves in position.

I decided to finish the boards by sanding them smooth, scorching them lightly with a burner and using 3 coats of a clear matt varnish to seal them.

Since my cuts weren’t perfect, the shelves didn’t always come out level when I put the scaffold in the slots so I hammered thin pieces of wood or shims into the gaps to level each shelf and then cut off the excess. This also worked to wedge the shelves into the gaps more securely.

If I made these again I would probably add a way of fastening the shelves more permanently or a metal cuff to go round the board to stop the box section chewing into them but they work well, I just can’t climb up the ones that are only held by one piece of box section.

I hope you have fun having a go, I know there are a bunch more things I could improve but the concept and method is there so if you find a way to do it better or differently, I’d love to see it. Happy building!

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