Fit a tumble dryer vent kit through an outside wall

Core-drill a vented dryer hose through an outside wall, check for gas flues and hidden pipes first, then fit a sealed outside cowl.

TD-01Check your dryer is a vented modelVented tumble dryers push hot, damp air out through a hose to the outside. Condenser and heat-pump dryers don't vent anywhere at all - they collect the water in a tank or pump it away, so they don't need this kit. Check your dryer's manual or look for a hose spigot on the back of the machine. If there's no spigot, stop here - you have a condenser or heat-pump dryer and this job isn't for you.

TD-02Check for open-flued gas or solid fuel appliances in the roomIf the room has an older gas boiler, a gas fire, or a solid fuel stove that draws its combustion air from the room rather than a room-sealed balanced flue, a running vented dryer can pull flue gases back down the flue and into the room. Get a Gas Safe registered engineer to check a gas appliance, or a HETAS installer to check a solid fuel one, before you fit the vent. Fit a carbon monoxide alarm in the room either way, and hold off using the dryer until it's been checked.

RULES

1 each · Carbon monoxide alarm

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KNOW THE RULES

By law, only a Gas Safe registered engineer may work on or check gas appliances and flues. If a room has an open-flued gas or solid fuel appliance, get it checked before fitting a vented dryer and fit a carbon monoxide alarm.

TD-03Plan the vent routePick the shortest, straightest route from the dryer to an external wall - every bend in the hose adds resistance and cuts how well the dryer dries. Check your dryer's manual for the maximum hose length, usually around 2-3m with no more than two bends. Outside, make sure the cowl position is well clear of any boiler flue terminal, airbrick, or window that opens, and low enough to reach safely. A ladder is only for a ground-floor wall at a low height: if the cowl would sit any higher, get a professional to drill and fit it.

TD-04Work out what your wall is made ofTap the wall: a dull, solid knock means brick or block; a hollow knock means a stud wall or dot-and-dab plasterboard over masonry. On a hollow wall, use a stud detector or a magnet to find the screw heads holding the plasterboard, usually at 400mm or 600mm centres - that's your timber stud or metal frame. A small pilot hole tells you more: timber dust means a timber stud, fine grey swarf means a metal stud, and breaking through after only 10-15mm into a gap means dot-and-dab or lath and plaster over solid masonry behind. Whatever the inside finish, the outer leaf of most external walls is solid brick or block, so the core-drilled hole itself is almost always through masonry - the construction mainly changes your sleeve length and how you patch around the hole inside.

TD-05Safety checks before you drill or cutCables and pipes can run almost anywhere in a wall, not just in the obvious safe zones, and they can be deep, in metal conduit, or hidden behind metal-backed board - a detector can miss them, especially through a metal stud frame. Run a cable and pipe detector over the whole drilling area, but still assume something could be there until a careful pilot hole proves otherwise. 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 circuit at the consumer unit before you drill, and know exactly where that stopcock is before you cut into anything that could carry water.

1 each · Cable, pipe and stud detector

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TD-06Hire the core drill and mark the holeHire a 100mm or 110mm diamond core drill from a tool hire shop - this cuts a clean, round hole through brick or block that a standard SDS drill can't manage. Mark the centre of the hole on the inside wall, then drill a small pilot hole right through to the outside so you can see exactly where it comes out and double-check the outside position still clears any flue terminal or airbrick. Set the core drill to a slight outward fall, about 5-10mm lower outside than inside, so rain runs away from the house rather than back into the room.

1 day · 100mm diamond core drill, day hire

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1 each · Long pilot drill bit

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TD-07Drill through the wallDrill from the inside using the pilot hole as your guide, letting the core bit do the work rather than forcing it - solid brick or block can take a few minutes per 100mm of wall thickness. If the inside of the wall is a timber or metal stud frame, place the hole in the gap between studs. Never core-drill through a stud: a 100mm hole would cut most of it away, so move the hole instead. Wear safety goggles and a dust mask, and vacuum up brick dust and metal swarf as you go - it's heavy and gets everywhere.

1 each · Dust mask

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1 each · Safety goggles

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TD-08Fit the sleeve through the wallPush the plastic sleeve supplied with the kit through the hole until it sits flush with the outside wall face, trimming it to length with a hacksaw if the wall is thicker than standard. On a dot-and-dab wall, remember the hole passes through an extra 25-50mm of adhesive dabs and air gap before reaching the masonry, so check the sleeve still runs right through to the outside face. Pack any gap around the sleeve with mineral wool insulation, then seal both ends with silicone to stop draughts and keep water out.

1 each · 100mm vent sleeve

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1 each · Mineral wool insulation offcut

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1 tube · Exterior-grade silicone sealant

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TD-09Fit the outside cowlFit the external cowl over the sleeve so its flap hangs correctly and opens outward when the dryer is running. Fix it to the wall with the screws and plugs supplied - into solid masonry use the plug and screw size the kit specifies, typically a 6mm plug and a 40-50mm screw; if the outside face is timber cladding, use wood screws into a solid batten instead. Run a bead of exterior-grade silicone sealant right around the cowl's edge to stop water getting in behind it.

1 each · External vent cowl with flap

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1 pack · Wall plugs and screws (pack)

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TD-10Connect the hose insidePush the flexible hose onto the dryer's spigot and onto the sleeve, securing both ends with the jubilee clips supplied. Keep the run as short and straight as possible, well within the manufacturer's maximum length, and avoid any sagging dips where lint and condensation can collect. Support the hose so it can't kink or get crushed behind the dryer.

1 each · Flexible vent hose, 3m

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2 each · Jubilee clips

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TD-11Test run and checkRun the dryer on a normal cycle and go outside to check the cowl flap opens and air is flowing out steadily. Check inside for any draught or water coming back through the sleeve, and check around the cowl outside for leaks over the next few days of wet weather. If the room has an open-flued appliance you had checked earlier, make sure the carbon monoxide alarm is fitted and working before you rely on the vent day to day.

TD-12Clean up and keep it maintainedClean the lint filter after every single load - it only takes a few seconds and it's the biggest fire risk if you skip it. Clean the full hose and cowl flap a few times a year, as lint builds up inside the hose even with a clean filter, and clear any outside build-up so the flap can shut properly when the dryer isn't running. Sweep up and vacuum any brick dust left from drilling, and make good any plaster or paintwork around the inside opening.

1 each · Flexible hose cleaning brush

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PART OF A BIGGER PROJECT

Set up a utility area

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