Fit bay window blinds to a lath and plaster wall — HomeGraft

Fit bay window blinds safely by checking each wall type, choosing the right fixing, and levelling every bracket.

BW-01Unpack the kit and check what you've gotLay out all three (or more) blinds for the bay and check each one matches its recess — bay window blinds are usually cut to fit a specific side, so don't mix them up. Check the brackets, screws and fixings supplied are the right ones for your wall — often they aren't, especially in older houses, so read ahead before you assume the bag of screws in the box will do the job.

1 set · Bay window blind set (3 blinds)

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BW-02Measure each recess separatelyMeasure the width and depth of each of the three window recesses in the bay — they are rarely identical, even in a new bay. Measure top, middle and bottom of each recess, since old timber and brickwork move over time. Write the smallest width down for each recess and use that for ordering or trimming battens.

1 each · Tape measure

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BW-03Work out what's behind each reveal and the headA bay window can mix wall types in one job: solid brick or block reveals, a lath and plaster wall or ceiling above, or a timber or metal stud wall if the bay was rebuilt or extended. Tap the surface — solid brick sounds dead and hard, lath and plaster and stud walls sound hollow and slightly springy. Run a magnet or stud detector along the fixing line: regular clicks every 400-600mm mean studs; a dragging magnetic pull along a continuous line under the plaster suggests a metal stud frame or metal-backed board. Drill one small 3mm pilot hole at a proposed fixing point — brick dust means masonry, pale timber dust means a wood stud or lath, and fine grey swarf means a metal stud.

1 each · Stud and cable detector

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1 each · 3mm HSS drill bit

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BW-04Mark and level the bracket positionsHold a bracket in place at the height given in your blind's instructions and mark the fixing holes with a pencil. Use a spirit level to check the bracket is dead level before marking — an out-of-level bracket will make the blind hang crooked across the whole bay. Repeat for every bracket on every recess before you drill anything.

1 each · Spirit level (250mm)

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1 each · Pencil

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BW-05Check for cables and pipes, and know your isolation points, before you drillCables and pipes can run almost anywhere behind a wall or ceiling, not just in the usual safe zones — this is especially true near a bay window where wiring for lights, curtain tracks or old sockets may have been run. Use your detector, but still treat every fixing point as if something is there until you've drilled a small pilot hole and proved otherwise. Before you start, 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 at all, isolate the relevant circuit at the consumer unit before drilling, and know where the stopcock is before cutting into anything that could carry water.

BW-06Fix brackets on a lath and plaster wall or ceilingLath and plaster is brittle and will crack if you screw straight through it into thin air. Find the timber upright or joist behind the laths using the same method as finding a stud, then drill a fine pilot hole through the plaster and lath into solid timber. Use a 45-50mm wood screw so it bites well into the timber behind, not just the lath, and drive it slowly to avoid cracking the surrounding plaster. If a fixing point falls between timbers, don't just rely on the lath — fit a short timber batten screwed to the studs either side to spread the load.

8 each · Wood screws 45-50mm

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1 length · Timber batten 25x50mm (for spreading load)

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BW-07Fix brackets into solid brick or block revealsDrill a 7mm hole for a standard wall plug, or 6mm for a smaller fixing, going 5mm deeper than the length of the plug so dust doesn't stop it seating fully. Vacuum the dust out of the hole, tap in the correct wall plug, and drive the screw in until the bracket sits tight and flat against the reveal. Solid masonry gives the strongest, most reliable fixing in a bay, so use it as your reference point if brackets on other reveals feel less secure.

8 each · Red/brown wall plugs

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8 each · Screws 40mm

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BW-08Fix brackets into a timber stud wall (if the bay was rebuilt or extended)Drive a wood screw straight into the centre of the stud — aim for the middle so you don't split the timber edge. A 40-50mm screw is usually enough to hold a light bay window blind bracket. If a bracket position falls between studs, don't fix into plasterboard alone; move the bracket to line up with the stud, or fit a noggin between the studs first.

8 each · Wood screws 40-50mm

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BW-09Fix brackets into a metal stud wall (if the bay was rebuilt or extended)Never use a plain wall plug or an ordinary wood screw in a metal stud — it will strip straight through 0.5mm steel and pull out under load. Use a self-drilling metal-stud fixing or a toggle-type hollow-wall anchor rated for the bracket's weight. Bay window blinds are light, so a small toggle fixing is normally enough, but if a bracket falls between studs on plasterboard alone, check the toggle is rated for the actual pull force of the blind mechanism, not just its static weight.

8 each · Self-drilling metal stud fixings

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4 each · Toggle-type hollow wall anchors

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BW-10Fix brackets on dot-and-dab plasterboardDot-and-dab plasterboard has an air gap of 10-40mm behind it before you reach solid masonry, so a fixing that's the right length for a solid wall will be too short here. Use a long fixing — typically 60-75mm — designed to pass through the plasterboard and gap and bite into the masonry behind. A standard toggle fixing that only grips the plasterboard is not strong enough for a bracket taking regular pulling force from a blind cord or wand.

8 each · Long fixings for dot-and-dab (60-75mm)

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BW-11Hang the blinds and test each oneClip or slot each blind onto its brackets following the maker's instructions, then check it sits square in the recess. Raise, lower and tilt each blind fully to check the mechanism runs smoothly and the brackets don't flex or creak under use. Re-check level across the whole bay by eye from a few steps back — small differences between the three recesses show up clearly once all the blinds are hanging.

BW-12Tidy up and make goodVacuum up all drilling dust and debris from the windowsills and floor, especially plaster dust from lath and plaster work, which can be fine and get everywhere. Fill any chips or small cracks in the plaster around the brackets with a quick-set filler and leave to dry before touching up with paint. Put dust sheets and tools away once the area is clean.

1 tub · Quick-set filler

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1 each · Dust sheet

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