Fit a new drain cover or gully grid

Replace a worn or broken drain cover or gully grid safely, matching the size and load rating to where it sits.

DC-01Work out what you're replacingA gully grid sits over a small yard gully that takes rainwater from a downpipe. A drain cover sits over a manhole or inspection chamber for underground pipework. Check the material (cast iron, galvanised steel or plastic) and whether it's round or square, recessed or solid-top.

DC-02Measure up and buy the right replacementMeasure the clear opening and the frame, not just the visible cover, as sizes vary by a few mm. If the drain sits under a driveway or anywhere a car crosses it, buy one rated for vehicle loads, not a pedestrian-only one.

RULES

1 each · Replacement drain cover or gully grid

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1 each · New frame (if old one is cracked or corroded)

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KNOW THE RULES

This isn't a legal rule for homeowners, but covers are rated to BS EN 124: lighter classes (A15/B125) suit gardens and paths, heavier classes (C250/D400) are needed under driveways. Fitting a light-duty cover under a car will crack it.

DC-03Protect yourself before you startDrain covers can carry bacteria, so wear gloves and don't touch your face. Keep a bucket handy for debris rather than putting it straight on the grass or patio. If it's an old cast iron cover, get help lifting it — they're heavier than they look.

1 pair · Rubber gloves

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1 each · Bucket

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DC-04Lift out the old cover or gridUse a cover lifting key in the keyholes, or a flat-bladed screwdriver worked gently around the edge to break any old mortar or rust seal. Lift it straight up rather than dragging it, and set it down away from the opening so you don't trip over it.

1 each · Drain cover lifting key

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DC-05Clean out the gully or chamberScoop out leaves, silt and debris with a gloved hand or small trowel and put it in the bucket, not down the drain. Check the pipe below isn't blocked further in. Pour a bucket of water down to confirm it flows away freely before you fit anything new.

1 each · Small trowel

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DC-06Check the frame and seatingIf the old frame is cracked, loose or rocks when pressed, it needs resetting. Rake out any old crumbling mortar with a chisel or the corner of a trowel, then brush out the dust and debris so the new mortar bonds properly.

1 each · Cold chisel

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1 each · Stiff brush

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DC-07Bed the new frame in mortar (if replacing one)Mix a small batch of mortar at roughly 4 parts sand to 1 part cement, fairly stiff. Lay it around the opening, press the frame in, and check it's level and flush with the surrounding surface with a spirit level. Leave it to firm up for at least a few hours, ideally overnight, before putting any weight on it.

1 bag · Sand and cement mix (small bag)

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1 each · Spirit level

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DC-08Fit the new cover or gridDrop the new cover or grid into the frame and check it seats flush without rocking. If it has retaining screws or bolts, tighten them evenly so the cover sits level all round.

1 each · Screwdriver or spanner (to match fixings supplied)

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DC-09Test itPour a bucket of water down to check it drains away properly and nothing leaks around the frame. Check the cover doesn't wobble or sit proud — a raised edge is a trip hazard, especially on a path or driveway.

DC-10Tidy upTake the old cover to a scrap metal or household recycling point rather than the general bin — cast iron and steel are both recyclable. Wash your gloves and tools, and wash your hands well since you've been handling drain debris.

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