Alcove shelving looks like the easiest job in the house. Then you measure it. The wall at the top is wider than the wall at the bottom, the floor slopes towards the door, the skirting is 140mm tall on one side and 120mm on the other, and the cornice has been run by hand so no two profiles line up. None of this is unusual. It is simply what old houses do, and it is why measuring deserves more time than cutting.
Get the numbers right and the build is straightforward: panels cut to size, scribed fillers to take up the wobble, shelves that sit level. Get them wrong and you will be planing in a cold garage at nine in the evening, wondering where it all went sideways.
Measure the alcove in three places, then work to the smallest number
An alcove is rarely a rectangle. Treat it as a slightly irregular box and measure the width at the bottom, at waist height and just under the cornice. Do the same for height at the left edge, the centre and the right edge. Take the depth from the front of the chimney breast to the back wall at the top and at the bottom.
The rule is simple: your carcass has to fit through the tightest point, so build to the smallest width and the smallest height, not the average. If the narrowest reading is 1,180mm and the widest is 1,215mm, plan for 1,180mm and use fillers to close the gaps at the sides.
Sketch it on paper with the real numbers written on the drawing. Photographs on a phone are useful for remembering where the socket was, but they are hopeless for a cutting list.
Note everything that is already in the way
Before you decide on dimensions, walk the alcove and list the obstacles. Most of them will change your design rather than stop it.
- Skirting boards. Note the height and the profile. Shelving usually sits in front of the skirting, or the skirting is cut away and the uprights run to the floor. Both work; the second looks tidier.
- Coving or cornice. Measure the drop and check whether the profile is straight or has a curve that eats into the top of the alcove.
- Picture rails, dado rails and wall vents. A vent must stay clear. A rail can be removed or worked around.
- Radiators, pipes and cables. Leave room for airflow around a radiator, and never bury a cable you might need to find again.
- Sockets, switches and aerial points. Decide now whether they will sit inside a shelf bay, be moved, or be covered. If anything electrical needs relocating, that is a job for a qualified electrician.
- The wall itself. Tap it. Solid brick, plasterboard on studs and lath-and-plaster all need different fixings. Lath-and-plaster is common in older properties and is not strong enough to hold heavy shelves on its own.
- Damp or staining. If you see tide marks or smell mustiness, sort the cause before you box the area in. Shelving over a damp patch traps the problem.
Also check the swing of any nearby door, and the drop of a curtain pole or blind. A shelf that fouls a door handle is an annoying thing to discover after painting.
Check the levels, because nothing here is level
Use a long spirit level — a 1,200mm one is far more useful than a 600mm one — and a straight edge. Check the floor across the alcove in both directions, and check the ceiling the same way. Then check whether the side walls are plumb by holding the level vertically against each one.
For square, measure the two diagonals of the alcove opening. If they differ by more than a few millimetres, the alcove is out of square and one side will need scribing.
Two techniques solve almost all of this. First, build the unit to the highest point of the floor and use adjustable feet or a plinth to take up the difference at the low end. Second, cut uprights slightly short at the top and finish with a scribed filler piece shaped to the ceiling or cornice. A scribe is a piece of timber cut to follow an irregular line; a comb or profile gauge makes the shape easy to transfer.
Work out depth and shelf spacing from your own books
This is the one measurement you should take from your belongings rather than from a rule of thumb. Pull out the tallest, deepest books you own and measure them. Most hardbacks fit within 300mm of depth, but art books, atlases and box files can need 350mm or more.
For shelf spacing, 320mm to 350mm between shelves covers most fiction and non-fiction. Add a taller gap of 400mm or so at the bottom or top for oversized items. A4 folders need about 320mm of clear height.
Shelf thickness matters more than people expect. An 18mm shelf will sag over a long unsupported span, so plan on a vertical divider or a support roughly every 750mm to 900mm for ordinary book loads.
Decide the construction before you order timber
Fixed shelves are stronger, cheaper and quicker to build. Adjustable shelves on drilled and bushed holes give you flexibility later, which suits a wall that will hold a changing mix of books, boxes and ornaments.
Think about how the top meets the cornice. A common approach is to stop the shelving below the coving and finish with a plain filler, which reads as intentional rather than fudged. Then decide how many bays you want. Two bays in a wide alcove look calmer than three narrow ones.
Draw it, then write a cutting list
Produce a simple elevation drawing — the view from the front — plus a plan showing depth. Mark the smallest width and height on it, and write down the skirting and cornice deductions. Then list every part: uprights, shelves, back panel, plinth, fillers, fixings.
Allow a scribe margin of about 10mm on each side upright if the walls are rough, and remember that uprights cut from a single sheet are usually limited to the board length. If your ceiling is 2,400mm high, a one-piece upright may not be practical.
A final check before you commit
Mark the outline of the unit on the wall in pencil and stand back. Check that the shelf heights sit well against eye level and that sockets remain reachable. Then confirm the wall construction and fixings, deal with any damp or ventilation first, and get a professional in for anything involving gas, mains wiring or moving a meter.
Measure twice, write it down, and build once. The alcove will still be slightly out of square — but you will have planned for it.
Photo: garten-gg / Pixabay
