BATHROOMS

Fit a shower caddy or corner shelf to a lath and plaster wall

Fit a bathroom shelf securely by finding solid fixing points behind the wall, drilling carefully, and sealing the holes against water.

SC-01Plan the job and prepare the areaDecide where the caddy or shelf will go - a corner near the shower is common, but avoid grout lines and sealant joints where you can, since a fixing needs solid material either side of the hole. Lay an old towel in the bath or shower tray to catch dust and stop chips damaging the enamel. Get all your tools and fixings together before you start. Mark your planned hole positions lightly with a pencil, then hold the shelf up and check it with a spirit level.
1 each · Shower caddy or corner shelf
1 each · Old towel or dust sheet
1 each · Pencil
1 each · Torpedo spirit level
SC-02Work out what's really behind the wallLath and plaster walls have timber laths nailed to timber studs, usually 400mm to 600mm apart, with a layer of lime plaster keyed behind the laths - a fixing needs to reach the stud, not just the lath, for real strength. Run a detector over the marked area, then tap gently: a dull, solid sound usually means a stud is close, a hollow sound means you're on lath alone between studs. If your wall turns out to be plasterboard on a stud wall rather than true lath and plaster, check whether the studs are timber or metal - a magnet grips a steel stud through the board, and a small pilot hole brings out fine steel swarf instead of timber dust. This matters because the fixing is different for each, covered in the next step.
1 each · Multi-detector (stud/cable/pipe)
1 each · Small magnet
SC-03Check for pipes and cables, then drillCables and pipes can run in places you don't expect, especially near a shower where shaver sockets, extractor fans and shower feeds are common. Run your detector over the area again right before drilling, but still treat the wall as if something is there - detectors miss cables that are deep, in metal conduit, or behind metal-backed board. Find your stopcock, usually under the kitchen sink, and check it turns before you start, so you can shut the water off fast if you hit a pipe. If you have any doubt at all, isolate the electrics at the consumer unit and turn the water off at the stopcock before you drill. Drill through the tile first with a tile or spear-point bit, then swap to the right bit for your wall - masonry bit for brick or block, a wood twist bit for timber studs, or a smaller pilot bit for lath and plaster or metal stud. Go slowly and let the bit do the work; forcing it cracks tiles and old plaster.
1 each · Tile/spear-point drill bit
1 each · Masonry drill bit 6mm
1 each · Wood twist drill bit 4mm
SC-04Fit the right fixing for your wall typeLath and plaster: drill a pilot hole into the timber stud behind the lath and use a 40-50mm countersunk wood screw into the stud centre; if you must fix between studs, use a spring or self-drilling cavity fixing, since bare lath is fragile and a plain screw can crack the plaster or pull straight through. Solid brick or block: drill 6mm, insert a wall plug 35-40mm deep, then drive a 40mm screw home. Plasterboard on timber studs: screw a 40mm wood screw straight into the stud centre; between studs, use a cavity toggle rated for at least 5kg. Plasterboard on metal studs: never use a plain plug or wood screw, which strips straight through 0.5mm steel - use a self-drilling metal-stud fixing or a toggle-type hollow-wall anchor, and if the shelf is heavy or gets knocked or pulled, fit a timber noggin or pattress between the studs, or fix through to the masonry behind. Dot-and-dab plasterboard: use a long fixing, 75-100mm, that passes through the board and the adhesive dabs to bite into the solid masonry behind - a plug sized for plasterboard alone will not hold.
4 each · Countersunk wood screws 40mm
4 each · Wall plugs (masonry) 6mm
2 each · Cavity toggle fixings (5kg rated)
2 each · Self-drilling metal stud fixings
2 each · Long fixings for dot-and-dab 75mm
SC-05Mount the shelf and check it's levelOffer the bracket or shelf up to the fixings and drive the screws home, but don't overtighten into lath and plaster or you risk cracking the surrounding plaster. Check the shelf with a spirit level once it's up and adjust before the fixings are fully tight if you can. Give it a firm push and a gentle pull to test it holds before loading it with bottles.
1 each · Screwdriver or drill/driver
SC-06Seal around the fixings and shelf edgeRun a thin bead of sanitary silicone around the top edge of the shelf where it meets the wall, and dab a little into any gap around the fixing holes. This stops water tracking behind the shelf and into the plaster or plasterboard, which matters most on lath and plaster where damp causes real damage. Smooth the bead with a wet finger or a sealant tool for a neat finish.
1 each · Sanitary silicone sealant
1 each · Sealant smoothing tool
SC-07Clean up and leave it to cureWipe away any dust or plaster debris and remove your dust sheet or towel. Leave the silicone to cure for at least 24 hours before the shelf gets wet, and hold off loading it with heavy bottles until then. Check the fixings again after a week of normal use, since old lath and plaster can settle slightly around a new hole.
1 each · Damp cloth

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