Replace a chimney cooker hood like-for-like on a timber stud wall

Take down your old chimney cooker hood, fit the new one safely, and reconnect the ducting and power in one session.

CH-01Clear the area and gather your toolsMove pans, oils and seasoning off the hob and worktop, and lay a dust sheet over the hob to catch screws and debris. Set up a stable step ladder if the hood is above head height, and check it's on level ground. Unbox the new hood and check the fitting instructions for any differences from the old one, such as bracket hole spacing. Have your drill, screwdriver, spirit level, tape measure and detector ready before you start.

1 each · Dust sheet

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CH-02Isolate the power supplySwitch off the cooker hood at its wall switch or fused connection unit, then turn off the matching circuit at the consumer unit. Prove the circuit is dead at the hood's connection point using a voltage tester before touching any wiring. Leave a note on the consumer unit so nobody switches it back on while you're working.

CH-03Take down the old hood and chimneyUnclip or unscrew the decorative chimney flue sections and lift them off the wall bracket. Disconnect the ducting from the top of the hood body, then support the hood while you remove the mounting screws from the bracket. Undo the electrical connection at the fused connection unit, or unplug it, and lower the hood carefully — it's heavier than it looks.

CH-04Check the new hood fits the same fixingsCompare the new bracket's hole spacing and duct size against the marks and holes left by the old one. Like-for-like hoods usually reuse the same holes, but check the duct spigot size (commonly 100mm or 150mm) matches your existing ducting. If the spacing is different, fill the old holes and let the filler dry before you drill new ones.

1 tub · Multi-purpose filler

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CH-05Check for hidden cables and pipes before drillingCables and pipes can run almost anywhere behind a kitchen wall, especially near existing sockets, switches or an extractor spur. Use a cable and pipe detector along your fixing line, but still assume something could be there — detectors miss cables that run deep, sit in metal conduit, or hide behind metal-backed plasterboard, and a metal stud frame confuses cheap detectors further. Find your stopcock (usually under the kitchen sink) and check it turns freely, so you can shut the water off instantly if you hit a pipe. If you have any doubt at all, isolate the circuit at the consumer unit before you drill.

1 each · Cable and pipe detector (if not already owned)

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CH-06Identify your wall typeOlder houses often have solid brick or block behind the hob; newer flats and refitted kitchens often use plasterboard on timber or metal studs, or dot-and-dab plasterboard over blockwork. Tap the wall — a dull thud means solid masonry, a hollow sound means stud or dot-and-dab. Run a magnet or detector along the fixing line: regular grips mean a metal stud frame, and a line of screw heads at set spacing marks a timber stud centre. Drill a small pilot hole at your marked point — timber dust means a wood stud, fine grey swarf means metal, and no resistance means you're between studs or in a dot-and-dab void.

CH-07Drill and fit the right fixing for your wallSolid brick or block: drill a 6mm hole 40mm deep, fit a masonry plug, and use a No.8 wood screw. Timber stud: drill a 3mm pilot hole into the centre of the stud and use a 40-50mm wood screw — never rely on the plasterboard alone. Metal stud: use self-drilling metal-stud screws or a toggle-type hollow-wall anchor rated for the hood's weight — never a plastic wall plug or an ordinary wood screw, which strips straight through 0.5mm steel; if the bracket will pull on the wall as the hood is used, fix into a timber noggin or through to the masonry behind instead. Dot-and-dab or lath and plaster: use a long fixing (60-75mm) that passes through the plasterboard and adhesive dabs or laths into the solid wall or stud behind, checking depth with a bradawl first.

1 pack · Masonry plugs (pack of 10)

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1 pack · No.8 wood screws (pack of 10)

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

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1 pack · Toggle-type hollow-wall anchors (pack of 2)

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1 pack · 75mm frame fixings (pack of 4)

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CH-08Fit the bracket and hang the hoodHold the bracket against the wall, check it's level with a spirit level, and mark your fixing points. Drill and fix using the method for your wall type from the previous step, then tighten fully but don't overtighten metal-stud or plasterboard fixings. Lift the hood body onto the bracket and secure it with the retaining screws supplied.

CH-09Reconnect the ductingFit a new length of ducting if the old one is damaged or too short — rigid duct performs better than flexible hose. Push the duct onto the hood's spigot and secure with a jubilee clip or foil tape, then connect the other end to the wall or roof vent. Seal any joins so air can't leak into the kitchen or the loft space.

1 m · 100mm rigid ducting, per metre

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2 each · Jubilee clip

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1 roll · Foil duct tape

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CH-10Reconnect the electricsConnect the hood to the existing fused connection unit or plug, matching the original wiring — brown to live, blue to neutral, green/yellow to earth. Replacing a hood like-for-like on its existing connection point isn't notifiable work under Part P, as long as you're not adding a new circuit or moving the connection point. Turn the circuit back on at the consumer unit and test the hood's lights and fan speeds before fitting the chimney covers.

RULES

KNOW THE RULES

Part P of the Building Regulations covers electrical work in kitchens. Simple like-for-like reconnection on the existing connection point isn't notifiable, but a new circuit or a moved connection point is — check with a registered electrician if unsure.

CH-11Fit the decorative chimney sectionsSlide the telescopic chimney sections up into the ceiling void and screw the top bracket to the wall or ceiling using the same fixing method as before. Slot the lower section down over the hood body so it hides the ducting and bracket. Check both sections sit level and adjust before final tightening.

CH-12Test the extraction and check for leaksRun the hood on full speed and hold a tissue near the outside vent to check air is flowing out. Check all duct joints and the wall vent for gaps, and reseal any that leak with more foil tape. Wipe down the grease filters and refit them.

CH-13Tidy upSweep up dust and screws from the hob and floor, and remove the dust sheet. Dispose of the old hood and packaging responsibly — many councils collect small electricals separately from general waste. Store spare fixings and instructions somewhere you'll find them again.

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