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How to Make a Corner Wall Shelf Unit

My aim with DIY projects around the home is to look for innovative space-saving ideas and save costs on materials by recycling.

Our new wall mounted desktop corner unit in our home office.

Our new wall mounted desktop corner unit in our home office.

How I Made a Desktop Corner Unit for My Home Office

During our last major home office makeover ten years ago, I made a desktop corner unit from pine floorboards. It served its purpose, but the four issues with it were:

  • The side leg supports sitting on the desktop restricted desk access.
  • The section of shelving against the back wall was a little too long and encroached on the space behind the monitor, making the space a little cramped.
  • The bottom shelf was just a tagged too low, so the stacked filing tray underneath was a tight fit.
  • I made the unit square, but (as common with old British homes) the corner wall was not straight, even or square, so the unit didn’t fit properly against the wall.

Therefore, as part of the office makeover I decided to make a new unit that resolved all of the above issues as follows:

  1. I would make the new unit wall mounted, rather than desktop standing.
  2. I would shorten shelving section against the back wall by about 6 inches, so that it wasn’t partly obscured by the monitor.
  3. I would design the new unit so that the bottom shelf would be about half an inch higher, to give some clearance for the filing tray underneath.
  4. I would make the new unit out of a square, to fit the corner wall.
The old corner unit which we were replacing.

The old corner unit which we were replacing.

Choosing Material and Recycling Wood

This time, rather than using pine floorboards, I opted to use 12 mm (½ inch) plywood for the shelving so that it could be cut to match the angle of the walls in the corner. The bonus in using plywood for the shelving is that I could make the front inner corner curved, rather than straight, to give the unit some shape and make it more aesthetically pleasing.

The new unit would be about 3 ft along its longer length along the side wall, and around 2 ft along the shorter length against the back wall. In order to make the three shelving sections I had to buy a sheet of 4ft x 8th plywood, however.

  • For the two outer side supports I used some of the spare pine floorboards leftover from making the bookcase for inside the office wardrobe, and
  • For the two inner shelf supports I recycled some of the pine wood left over from the redundant pine table I’d used to make the alcove shelving in the office.

How to Make and Fit the Corner Wall Unit

Before I could start making the wall unit I needed to determine the angle of the corner wall, and the overall dimensions for the unit.

Step 1: Determine Measurements

The measurements for the unit would be:

  • The length along the side wall could remain the same as the original unit e.g. three feet.
  • The length along the back wall needed shortening by about six inches e.g. to make it about two feet.
  • The overall height from underneath the bottom shelf, to the above the top shelf, needed shortening by just half an inch from the original; 540 mm (21 ¼ inches) instead of 550 mm.
  • The depth of the shelfs would be as before e.g. 140 mm (5 ½ inches).

Step 2: Ascertain the Correct Angle

As the corner wall was not square, after emptying the old shelving unit and removing it, the method I used to determine the actual angle was:

  1. Cut a piece of spare (scrap) 4mm plywood to 3ft x 2ft
  2. Hold it up in the corner of the wall, making it flush with back wall, at the height of the lower shelf to measure the gap between the plywood and side wall at the outer edge of the longer length.
  3. Repeat the process at the height for the top shelf e.g. to ensure there was no significant difference in angle that would need to be compensated for in the design and build.
  4. Use the measurement to cut the 4mm plywood sheet to the correct angle.
  5. Retest for fit.

Once I’d got the correct angle I then used the 4mm plywood sheet as a template for cutting the three shelves to that angle.

Old corner unit removed from our home-office desk, so that the new one could be wall mounted in its place.

Old corner unit removed from our home-office desk, so that the new one could be wall mounted in its place.

Step 3: Cut Shelves to Correct Size and Angle

  1. Measure, mark out, and cut three oblong sections from the 12mm plywood sheet to the overall outer measurements for the shelves.
  2. Using the 4mm plywood template, mark out the corner angle for the shelving on one of the three plywood sheets.
  3. Clamp the three sheets together and use a circular saw to cut the correct corner angle.

Step 4: Cut the Sides Supports to the Correct Size

  1. Use a bench mitre saw to cut the side supports to length.
  2. Clamp together the two outer supports and two inner supports and use the bench mitre saw to trim them all precisely to the same length.

Step 5: Cut the Shelving to the Final Shape

  1. On one of the plywood sheets for making the shelves (for the two adjacent sides), measure and mark the depth of the shelves, which for this project is 140 mm (5 ½ inches).
  2. Place a large paint pot (or similar) in the corner to align with the adjacent shelf width lines and mark a curve with a pencil to join the two straight lines.
  3. Clamp the three shelf sheets together and use a jig saw to cut the outer edge of the shelves to shape; following the curve marked out in the corner.
  4. Clamp the lower and middle shelves together and use a circular saw to cut the back corner. The back corner for the top shelf isn’t cut, as this will butt against the wall so that there’s no gap for things to fall down.

Step 6: Make the Joints for Fitting

The two outer supports would be jointed to the middle shelf with through dado joints, and the two inner shelf supports jointed to the middle shelf using slotting joints.

To make the inner shelf support joints:

  1. Measure, mark and cut the slots in the inner shelf supports, and chisel out with wooden mallet and chisel.
  2. Measure and mark for the corresponding slots in the middle shelf, and cut out with a jig saw.

To make the outer shelf unit support joints:

  1. Measure, mark and cut the slots in the outer shelf supports for the middle shelf, and chisel out with wooden mallet and chisel.
  2. Measure the thickness of the side supports and deduct the depth of the dado.
  3. Then use a saw to reduce the length of the middle shelf (at both ends) accordingly; so that when assembled, the overall measurements remain constant for all the shelves.

Step 7: Assemble the Wall Unit Carcass

  1. Apply a little wood glue, sparingly, to where the slotting joints will overlap in the middle section.
  2. Slot the two middle supports in place on the middle shelf.
  3. Glue and screw the two outer supports to the middle shelf.
  4. Glue and screw the top shelf in place.
  5. Clamp up the top shelf, to make it square with the unit, and glue and screw it in place.

Step 8: Make and Fit the Back Panels

For the two main back panels, I used the scrap wood that was left over from cutting out the shelves. I cut these to size and glued and screwed them to the back of the unit.

For the centre section I used some scrap 4mm plywood, cutting it to size and gluing in place. For added support (to hold the thin plywood in place) I used a piece of scrap wood which I glued and screwed to the top of the unit, fixed to the back of the unit, on the underside of the top shelf.

Step 9: Finishing Touches

Having made the unit, I then:

  • Used a belt sander to level off the plywood edges with the sides.
  • Used an orbital sander to round off all the edges and sides of the unit.
  • Wiped the whole unit over with white spirit to remove surplus sawdust.
  • Stained the unit with wood dye, and left to dry, and
  • Finally waxed and polished the unit with coloured beeswax.

Step 10: Hang the Wall Unit in Place

The unit would be secured to the wall with four screw, two in each side panel. Therefore, I drilled the four pilot holes in the back of the unit before fixing to the wall.

Also, to keep the unit in place (straight and level and at the correct height) while fixing it to the wall, I quickly cut three temporary leg supports from scrap wood.

Then to secure the unit to the wall, I:

  1. Propped up the unit on the desk, using the three temporary legs I’d made.
  2. Used a spirit level to check it was level e.g. in the event that the desk top wasn’t level I could have used wedges under one or more of the temporary legs to adjust the height slightly.
  3. Gently hammered screws through the four pilot holes to mark the spot for drilling the screw holes on the wall.
  4. Removed the wall unit out of the way, drilled the four screw holes in the wall, and tapped in wall plugs.
  5. Repositioned the unit on the temporary legs and then screwed it securely to the wall.
  6. Removed the temporary legs, so that the wall unit was ready for use.

Corner vs Straight Units

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Arthur Russ

Your Comments

Arthur Russ (author) from England on August 23, 2020:

Thanks Danny, glad to help.

Danny from India on August 23, 2020:

Very useful tips, Arthur. This will be helpful for me to expand my room space.

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