DOORS & JOINERY

Fit skirting board to a lath and plaster wall

Remove old skirting, find what's behind the lath and plaster, then fix and finish new skirting board securely and neatly.

LP-01Clear the room and protect the floorMove furniture away from the wall and roll back carpet, or protect flooring with a dust sheet. Take off any beading or carpet gripper rod that's in the way. Give yourself clear access to the full length of wall you're working on.
1 each · Dust sheet
1 roll · Masking tape
LP-02Take off the old skirtingScore along the top edge with a knife to break the paint seal, then work a bolster chisel behind the board and lever gently with a pry bar. Lath and plaster is brittle, so work slowly near the wall face to avoid pulling chunks of plaster off with the board. Pull out any old nails left in the wall as you go.
1 each · Bolster chisel
1 each · Pry bar
1 each · Claw hammer
LP-03Work out what's behind the lath and plasterLath and plaster walls are always fixed to timber, never metal studs, since the material predates metal stud framing by decades, so you can rule that out. Run a stud detector or a strong magnet along the wall at skirting height to find the line of nail heads holding the laths, and knock along the wall to feel for the hollow sound between fixings and the firmer sound over a stud or batten. If the wall feels solid everywhere and a pilot hole brings out brick or mortar dust rather than timber dust, you have lath and plaster on masonry with timber battens behind it, not a stud partition.
1 each · Stud and cable detector
1 each · Small magnet
LP-04Check for cables and pipes before you drillCables and pipes can run almost anywhere behind a wall, including up from sockets near skirting height, so sweep the area with a cable and pipe detector before drilling. Detectors miss things too, especially deep cables or ones in metal conduit, so still treat the wall as live until you've drilled a little and checked. Find your stopcock, usually under the kitchen sink, and check it turns freely, and if you're at all unsure, turn off the relevant circuit at the consumer unit before drilling near a socket or light switch.
LP-05Measure the wall and mark your fixing pointsMeasure each wall run and mark the centre of every stud or batten you found in step 3, working at a height that will be covered by the skirting board. Use a spirit level to carry these marks up the wall above where the top of the skirting will sit, so you can still see them once the board is held in place.
1 each · Tape measure
1 each · Spirit level
1 each · Pencil
LP-06Cut the skirting to lengthCut internal and external mitres to match your corners, and square-cut ends that will butt against a door architrave. Cut boards a fraction long rather than short, so you can trim for a tight fit. Wear eye protection when using a mitre saw.
4 metre · MDF skirting board
1 each · Safety glasses
LP-07Fix skirting into a lath and plaster stud partition wallDrill a 2mm pilot hole through the skirting at each stud mark to stop the wood splitting, then drive a wood screw into the centre of each stud. Space fixings roughly every 400-600mm along the run, matching typical stud centres, and keep screws away from the very top edge of the board where the plaster is thinnest. Never rely on nails alone into old lath and plaster, since the plaster around them can crumble over time.
20 each · Wood screws No.8 x 50mm
1 each · 2mm pilot drill bit
LP-08Fix skirting into lath and plaster on a solid masonry wallWhere the wall is solid brick or block behind timber battens, drill through the skirting, the plaster and the lath, then continue into the masonry with a masonry bit, allowing for the extra depth of the plaster and any gap behind the laths. Use a wall plug rated for the drilled depth and a screw long enough to bite at least 30mm into solid masonry, not just into the plaster or batten. Where a fixing point falls between battens with no masonry close behind, use a hollow-wall fixing sized for the load instead of a standard plug.
1 each · Masonry drill bit 6mm
20 each · Red wall plugs
20 each · Screws 60-70mm
4 each · Hollow-wall toggle fixings
LP-09Add grab adhesive for extra supportApply a zigzag bead of grab adhesive to the back of the board along its length, avoiding the fixing points. This spreads the load across old, fragile plaster and reduces the risk of cracking around the screws. Press the board firmly into place once you fix it, and wipe away any adhesive that squeezes out straight away.
1 tube · Grab adhesive
1 each · Caulking gun
LP-10Fit corners and glue the mitresApply wood glue to each mitre joint and pull the corner tight before fixing the board to the wall. Add a fine panel pin through the mitre itself, angled into the neighbouring board, to stop the joint opening as the wood moves. Wipe off excess glue straight away with a damp cloth.
1 bottle · Wood glue
20 each · Panel pins 40mm
1 each · Pin hammer
LP-11Fill holes and caulk the gapsFill screw and pin holes with wood filler and sand flush once dry. Run a bead of decorators caulk along the top edge where the skirting meets the wall, and along any tight butt joints, then smooth it with a wet finger.
1 tub · Wood filler
1 tube · Decorators caulk
1 sheet · Sandpaper
LP-12Paint and clear upApply primer to bare wood, then undercoat and a topcoat once fillers and caulk are fully dry. Sweep up dust and offcuts, and take old skirting and rubble to your local household waste site if it won't fit in your bin.
1 tin · Wood primer
1 tin · Undercoat
1 tin · Satinwood topcoat
1 each · Paintbrush

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