How do I lift a stuck manhole cover?

Freeing a cover that has been sealed by rust, mortar or paint, without breaking it or the frame, and putting it back so it lifts next time.

Difficulty: beginner
Time: 45 min
Read: 5 min
Safety: warning

Short answer

Clear the frame groove out with a screwdriver and a wire brush first — most stuck covers are held by grit and old mortar in the seating, not by rust. Then use proper lifting keys in the key holes, or a bolster tapped along the joint to break the seal. Grease the seating before you put it back and it will lift by hand next time.

Covers get stuck because the seating groove fills with grit, rust or the mortar from a resurfaced drive, and because nobody has lifted them in fifteen years. Almost all of them come up with patience and the right approach. Levering hard with a spade or a crowbar is what breaks covers, cracks frames and hurts people, and it is very rarely necessary.

Safety

An open chamber is a serious fall hazard, particularly for children — never leave one uncovered and unattended, not even for a minute. Drain water carries bacteria: wear waterproof gloves, avoid splashing, keep it away from your face and wash thoroughly afterwards. Never enter a chamber. Cast iron covers are extremely heavy and drop suddenly — keep fingers out from under the edge and boots clear of the frame.

What you'll need

Manhole lifting keys, matched to the cover type
Waterproof gloves
Screwdriver or a bent wire for clearing the groove
Wire brush
Bolster and a club hammer
Penetrating oil
Grease for reassembly
Timber blocks to rest the cover on (optional)

Inside an inspection chamber, and what a full one means

Step by step

Identify the cover type before pulling on anything.Two key holes at the ends is the common double-triangle or cast pattern taking a pair of lifting keys. A recessed tray cover filled with paving or concrete has hidden lifting eyes under the infill. Plastic covers usually have moulded slots and a screwdriver will do. Using the wrong key snaps the key or the lug.
Clear the seating groove all the way round.This is the step that does most of the work. Run a screwdriver or a stiff wire round the whole joint between cover and frame, digging out grit, leaf mould, moss and old mortar. Then brush it out. Many covers that would not move now lift by hand.
Soak the joint if it is rusted.Penetrating oil round the whole joint and half an hour to work. Repeat if it is badly corroded. There is no hurry here and the oil does more than force.
Break the seal with a bolster before lifting.Set a bolster into the joint at one corner and tap it — you are cracking the bond, not levering the cover. Work round the whole perimeter tapping at intervals. You will often hear and feel it release.
Use the keys correctly and lift with your legs.Both keys engaged, feet apart and clear of the frame, back straight, and lift by straightening your legs. A cast iron cover is heavy enough to injure someone if it is snatched.
Slide it clear rather than carrying it.Drag the cover off to one side rather than lifting and walking with it. Set it down on timber blocks so you can get your fingers under it again when it goes back.
Never leave the hole open.If you have to stop, put the cover back or cover the opening with something solid and weighted. An open chamber is a hazard for anyone in the garden and for animals.
Clean the frame and grease the seating before replacing.Wire brush the frame groove clean, then a smear of grease all round the seating. It stops the next seal forming and it will lift by hand in five years.
Seat it fully and check it does not rock.A cover that does not sit fully down rocks under foot, wears the seating and rattles under a car. Clear whatever is holding it up rather than treading it down.

Tips

Buy a pair of lifting keys rather than improvising. They cost very little and they are the difference between lifting a cover and damaging it.
Two people and two keys is much safer and easier than one person and two keys on a large cast cover.
Grease the seating every time you close it. It is a ten-second job that makes every future lift trivial.
Take a photograph looking down into the chamber, with the branches visible. It is genuinely useful information when a drain blocks later.
If the cover is in a drive, check its load class. A pedestrian-rated cover under a car will fail eventually, and the failure is sudden.

Common mistakes

Levering with a spade or a crowbar against the frame — It breaks the cover's edge, cracks the frame, and the tool slips. The cover is not held down by force, it is held by a filled groove — clear the groove instead.
Lifting with your back — Cast iron covers are heavy and awkward and they come free suddenly. It is one of the classic garden back injuries.
Leaving the chamber uncovered — It takes seconds for a child or an animal to fall in. If it is open, someone is standing over it.
Putting the cover back without cleaning the seating — You are guaranteeing the same struggle next time, and a badly seated cover rocks and wears the frame.

If it doesn't work

The lifting keys pull out or bend

Cause: Wrong key type, or the key holes are full of compacted grit so the key is not fully engaged. — Fix: Clear the key holes out completely with a screwdriver first. If the key still will not engage, you have the wrong pattern — take a photograph to a builders' merchant.

The cover has been concreted or tarmacked in

Cause: A drive or path has been resurfaced over it. — Fix: Cut round the frame with a diamond blade to release the covering material, then clear the groove as normal. Expect to have to make good the surface afterwards.

The frame is broken or the cover is cracked

Cause: Vehicle loading on a cover not rated for it, or previous levering. — Fix: It needs replacing rather than repairing — a cracked cover fails suddenly. Replace with a cover and frame of the correct load class and bed the new frame properly in mortar.

The cover smells even when closed

Cause: The seal has failed or the cover is not a sealed type on a foul chamber. — Fix: Internal chambers need a double-seal cover with a grease seal. External chambers do not, and a smell there points at the drain rather than the cover.

Questions people ask

Is it my manhole?

The chamber is usually yours if it only serves your property. Where it serves more than one property it is generally part of the public sewer and the water company is responsible for the pipe, although the cover in your garden may still be yours to maintain. Lifting a cover to look is fine either way.

What should I see inside?

A channel running through the base with shaped benching either side sloping into it, and one or more branch pipes entering. In normal conditions the channel is empty or running clear. Standing water means something downstream is restricted.

Can I replace a heavy cast cover with a lighter one?

Only if the load class is appropriate for where it is. A recessed tray cover or a composite cover of the right class is much lighter and can be filled to match the paving, and both are a real improvement in a garden. In a drive, the class is set by the vehicles.