How do I remove and replace this manhole cover?

[AdFromEssex]

Hello all,

I’ve had a good search but can’t seem to find an answer (apologies if this is infact a duplicate thread).

Can anyone advise the best way of removing this inset (I think that’s what they’re called) manhole cover?
The four screws are out but I don’t want to damage the screw holes by trying to pry it open.

Would this type have handles usually?

For background, it’s a manhole in the kitchen that’s been covered over by self-levelling compound and Karndean flooring. Sinks are draining slow and gurgling, and I can’t see another manhole (although I suspect one is under the shed).
Oh and if anyone finds them self in a similar predicament to me, a strong magnet trumped the Bosch Truvo multi-detector at locating the thing!

Thanks in advance.

 

[AdFromEssex]

If property has been extended (think you said it has!) then always possibility an inspection chamber has been 'buried' under flooring. (One of my pet hates!) Chambers are there for a reason, if neighbours have one then i'd try and identify which way the drains run. (Should run in a straight line between chambers.....)

If it looks like there may be a chamber somewhere under your floor then now may be the time to locate it. It's acceptable to have a cover internally, but must be correct type, with a cover that seals and is screwed down shut. It is a PITA to be called out to a drain problem, where no-one has any idea where the chambers are! Had occasions where a drain is blocked, and with no chambers and no idea where it might go, so we've had to dig, find the drain, then fit a chamber at an appropriate point for future needs.

@Hugh Jaleak it’s a follow-on from that other job (which is only 90% finished )

 

[^woody^]

What else goes into that chamber? It's unlikely to block just from a sink, and you don't really want to lift it if it's full of crap. Finding and lifting the next chamber may be better.

 

[Hugh Jaleak]

Remove screws and try these. Primaflow Galvanised Internal Manhole Cover Keys - Pack Of 2 | Wickes.co.uk

However, I'd expect it may be extremely tight, and might need some leverage around the edges to break the seal before it'll come up. Doing this without damaging anything is the tricky part.....

 

[AdFromEssex]

Oh hold on, maybe there isn’t a cover on it

 

[AdFromEssex]

Thanks for the responses above.
the bathroom WC basin and bath drain in to it, and it runs towards the sink that’s blocked.

Right, so I’ve learned today that the cover is actually concrete and without a metal base.

Based on the concrete now being removed and the likelihood of the cover being replaced for something that comes up to the floor level, I’ve cancelled the Wickes order for them keys.

Now I guess my question should be
what does this need replacing with?
Assuming it’ll be one of those covers where you see the outline within the flooring, it’ll need bringing up by 9mm.
I take it the whole thing needs replacing and not just the cover?

 

[Dereekoo]

Surely that cannot be right, a mass concrete lid. Are you sure there isnt a bit of nesh reinforcement further along, perhaps chip a bit more conc away. Are you sure the iron angle is not the edge of the lid

 

[AdFromEssex]

Surely that cannot be right, a mass concrete lid. Are you sure there isnt a bit of nesh reinforcement further along, perhaps chip a bit more conc away. Are you sure the iron angle is not the edge of the lid

You’re right - I was expecting a solid metal base, but it’s a grate of rebar type mesh:

To answer my own question, a sledgehammer and hammer + bolster - even with keys, I’d never have lifted it.

 

[HERTS P&D]

It looks like there is a frame.

Andy

 

[AdFromEssex]

Now I guess my question should be
what does this need replacing with?

Assuming it’ll be one of those covers where you see the outline within the flooring, it’ll need bringing up by 9mm to meet the level of the LVT.
I take it the whole thing needs replacing and not just the cover?

 

[Mottie]

Surely the angle iron and the rebar are part of the lid - the conc must surely be poured into that when making the thing. What were the screws holding down then?

 

[AdFromEssex]

Surely the angle iron and the rebar are part of the lid - the conc must surely be poured into that when making the thing. What were the screws holding down then?

Yes they are - I guess it either came pre-poured or it was filled at the time of fitting, and the lid has a rubber seal with the screws ensuring an air-tight fit.

 

[kingandy2nd]

It was a concrete lid before you smashed it!

I have them around my property.

I hope your one is a standard size so you can now replace it…I know mine aren’t

 

[Mottie]

My mate had a similar manhole cover in his kitchen extension in a house he bought in Stratford. It was under a false chipboard floor built on 1" battens. We lifted it up to look in out of curiosity to see in there and saw a very wide, fast flowing sewer!

 

[AdFromEssex]

…We lifted it up to look in out of curiosity to see in there and saw a very wide, fast flowing sewer!

I’ve got visions of the fridge scene from Ghostbusters 1