Fit magnetic secondary glazing panels

Fit a magnetic secondary glazing panel to cut draughts and noise, using the right fixing for your window reveal.

MG-01Check if you need permissionSecondary glazing itself needs no Building Regulations approval because it doesn't touch the original window. If your home is listed, altering the reveal - including fixing tape or screws - can need Listed Building Consent from your council, so check before you start. In a conservation area there's usually no extra permission needed for internal secondary glazing, but a quick call to the council's conservation officer is worth it if you're unsure.

RULES

KNOW THE RULES

Listed buildings may need Listed Building Consent before fixing anything to original window reveals - check with your council first.

MG-02Gather your tools and kitUnpack the magnetic secondary glazing kit and check it has the steel or aluminium tape strip, the magnetic acrylic panel, and any screws supplied. Lay out a tape measure, spirit level, pencil, screwdriver, drill with mixed bits, stud detector, masking tape and a cloth with mild detergent. Clear the windowsill and floor so you've got room to work and somewhere flat to trim the panel.

1 each · Magnetic secondary glazing kit

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1 each · Lint-free cloth

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1 bottle · Mild detergent

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MG-03Measure the revealMeasure the width at the top, middle and bottom of the window reveal, and the height at both sides and the centre - old reveals are rarely square. Use the smallest width and smallest height so the panel clears every point. Write the measurements on a strip of masking tape stuck to the frame so you don't lose them.

1 each · Tape measure

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1 roll · Masking tape

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MG-04Trim the panel to sizeMany kits are supplied oversized for you to cut down. Score acrylic sheet with a sharp knife against a straight edge and snap it along the line, or cut thicker sheet with a fine-toothed saw. Wear eye protection - the cut edge is sharp - and lightly sand it to remove burrs.

1 each · Trimming knife

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1 each · Fine-toothed saw

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1 each · Safety glasses

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1 sheet · Fine sandpaper

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MG-05Clean the reveal and dry-fit the panelWipe the whole reveal with mild detergent and water to shift dust, grease and any flaking paint, then dry it thoroughly - the adhesive tape only grips a clean, sound surface. Hold the trimmed panel in the opening to check it fits, and mark its final position lightly in pencil.

MG-06Work out what's behind the revealBefore you fix anything, find out what you're dealing with. Run a stud detector or a strong magnet slowly along the reveal, listening for a hollow sound between solid points and checking for a line of screw or nail heads under the plaster. A small pilot hole in an unobtrusive spot tells you more: pale timber dust means a timber stud, fine grey swarf means a metal stud, and brick dust means solid masonry. A reveal that sounds hollow all over but has solid masonry a short way behind is dot-and-dab plasterboard.

1 each · Stud detector

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MG-07Check for cables and pipes before drillingCables and pipes can run anywhere behind a reveal, even where a detector shows nothing - it can miss cables that are deep, in metal conduit, or behind metal-backed board, and a metal stud frame confuses cheap detectors further. Before you drill, find your stopcock (usually under the kitchen sink) and check it turns, 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 turn the water off at the stopcock before drilling anywhere it could hit a water pipe.

MG-08Fix the tape strip - method depends on the surfacePeel and stick the steel tape straight onto a sound timber window frame or reveal - no drilling needed. On flat, sound solid brick or block plaster, adhesive alone usually holds; on rough or flaking plaster, add a fixing every 300mm using a 6mm hole 30mm deep, a 5mm wall plug and a 30mm screw. On plasterboard over timber studs, screw into the centre of a stud with a 30mm wood screw wherever you can, and use a light-duty plasterboard anchor between studs. On plasterboard over metal studs, use a self-drilling metal-stud screw or a snap toggle made for hollow metal-stud walls - never a plastic wall plug or ordinary wood screw, which strips straight through 0.5mm steel. On dot-and-dab plasterboard, use a 60-75mm fixing long enough to pass through the board and adhesive dabs and bite into the masonry behind. On lath and plaster, tap to find a firm lath, drill a small pilot hole, and use a fine screw rather than forcing in a wall plug, which can crack the plaster.

1 pack · Wall plugs 5mm (pack of 10)

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1 pack · Wood screws 30mm (pack of 20)

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1 pack · Plasterboard anchors, light duty (pack of 10)

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1 pack · Self-drilling metal-stud screws (pack of 20)

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1 pack · Snap toggle fixings (pack of 4)

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1 pack · Masonry fixings 75mm (pack of 10)

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MG-09Fit the magnetic panelOffer the panel up to the fixed steel tape and let the magnets pull it into place - start at one edge and work across so it beds down evenly. Run a hand around the whole perimeter to check the seal is tight with no gaps. Open and close the panel once to make sure it lifts off and reseats cleanly.

MG-10Test and tidy upCheck the panel sits flush all round and doesn't rattle when you tap the window frame. Sweep up any dust or offcuts, and wipe fingerprints off the panel with a lint-free cloth - never a rough cloth or abrasive cleaner, which will scratch acrylic. Store any spare tape and fixings together in case you need to remove and refit the panel later for cleaning.

1 each · Lint-free cloth

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KNOW THE RULES

Before you start: Do I need Building Regulations approval to replace windows or doors?

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