Fit a wall-mounted letterbox to a rendered exterior wall

Mount a letterbox on a rendered exterior wall safely, checking for hidden cables and pipes before drilling into the masonry.

LB-01Plan the position and gather your toolsHold the letterbox against the wall at a comfortable height, usually 900-1100mm from the ground, so post is easy to push through. Mark the screw hole positions with a pencil and check with a spirit level. Make sure the spot is clear of pipework, cables or light fittings. Lay a dust sheet below to catch masonry dust.

1 each · Wall-mounted letterbox kit

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1 each · Spirit level

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1 each · Tape measure

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1 each · Dust sheet

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1 each · Pencil

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LB-02Check for cables and pipes before drillingCables for doorbells, porch lights and alarms often run near front doors, and a detector can miss anything deep in render or inside metal conduit. Sweep a cable and pipe detector over the marked area, then drill cautiously anyway, as if something could still be there. Find your stopcock, usually under the kitchen sink, and check it turns freely so you can shut the water off fast if you hit a pipe. If you have any doubt, isolate the nearby circuit at the consumer unit before you drill.

1 each · Cable and pipe detector

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LB-03Drill the fixing holes through render into masonryUse a 6mm masonry bit for a light letterbox or 8mm for a heavier one, matching the fixing pack supplied. Drill slowly through the render first to stop it cracking, then speed up to punch at least 40mm into the brick or block behind. Vacuum the dust out of each hole so the plugs grip properly.

RULES

1 each · Masonry drill bit 6mm

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1 each · Hammer drill

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1 each · Small vacuum or brush

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KNOW THE RULES

If your home is listed or in a conservation area, check with your local council before drilling into or altering the external render. Unauthorised work can be an offence under the Planning (Listed Buildings and Conservation Areas) Act 1990.

LB-04Fit wall plugs and screw the letterbox onPush a plug matching your screw size, typically a 6mm plug for a No.8 or No.10 screw, into each hole until it sits flush with the render. Screw the backplate on using screws at least 50mm long so they bite well into the masonry, not just the render skin. Tighten evenly so the letterbox sits flat and doesn't rock.

8 each · Wall plugs 6mm

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8 each · Zinc screws 50mm

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LB-05Seal the edges and check the flap moves freelyRun a bead of exterior-grade silicone sealant around the top and sides of the backplate where it meets the render, leaving the bottom edge open so trapped water can drain out. Open and close the flap a few times to check it swings freely and shuts fully. Wipe away any excess sealant with a damp cloth before it cures.

1 tube · Exterior-grade silicone sealant

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1 each · Damp cloth

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LB-06Tidy up and check the job the next daySweep or vacuum the masonry dust from the dust sheet and the ground below. Fold the dust sheet away for reuse and bag up any spare fixings. Come back after 24 hours to check the sealant has cured and nothing has worked loose.

1 each · Small storage bag

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