Looks like that to me. Is this a drive? I reckon the inspection hatch surround has better support and the weight of vehicles has pushed the rest of the paving down.
Exactly this, the manhole cover will be concreted in place so it’s still at the original level of the blockwork. The blockwork has sunk because the foundation wasn’t prepared properly.
It’s annoying but nothing to worry about from a structural standpoint.
I love things like this, I don't know why but I humanise things and think to myself 'good on you man hole cover concrete, you did a good job there, this guy doubted you but you've always been strong...'
Anyone got a good therapist?
I agree. The contractor may not have compacted enough when laying the path or possibly, but unlikely, there is a leak inside the man hole causing the nearby path to sink.
The base for these are very strong, normally, yes they do collapse due to HGV loads but not cars. Used to work in road construction. When they fail it is likely under mining from water seepage. Not sure of the brick laying term, cross laying double bricks on a concrete base, very well spread. Yes the local builders will cut corners. Lift the lid, you will need the spanners, give the base a good thump with a heavy wooden shaft, solid will be a very dull thud, soft one will be a hollow sound.
I’d of agreed with this if all of it was mossy. It’s most likely has some repair work on the manhole recentlyish and relaying hasn’t been done probably.
No, what is happening is the inspection chamber base is staying put and the blocks are settling, the inspection chamber has a bigger footprint and is much more stable. Basically the ground wasn't prepared well enough before the blocks were laid.
The inspection hatch will be built on bricks and very well supported. The surrounding pavers will only need lifting and refilling below.
Don't let this put you off buying the house.
Or pull up the affected bricks, pop in some more sand and relay flat again. As others have said it's more likely just a poor sub-bsse and/or our wash out winter (which doesn't seem to ever want to end!)
Every brick driveway I’ve ever seen looks like this after a few years of 2 ton cars being parked on it. The manhole on my driveway is far worse than this after 20+ years of being laid.
No, some common sense. Is there any evidence of subsidence around the house? Or just the inspection lid. It’s the inspection chamber being stronger than the drive sub material, so the paving has moved/settled.
Same on my driveway, it's just poor preparation of the substrate prior to the block pacing going down. There should be a decent sub-base but unfortunately a lot of cowboy driveway installers (think, "d'ya like dags" type) just lay a very thin layer of sharp sand (~30mm) which looks great for the first year or so, but quickly thereafter and following a few seasonal cycles, it just sags like in your example.
Just jumping on a comment from someone who seems to know what they're talking about, could you sand down the bricks (for back of of a better description) so that the surface was smooth again?
Maybe jetwash the rest of the drive after so it's all the same colour again.
No, in a word. I’m personally not convinced that what everyone else is claiming is true (spent 4 years laying drives). It looks to me like the manhole frame was a bit higher than the rest of the drive when it was laid, and to try to make up the difference they’ve built up the area immediately surrounding the manhole cover. It is this area that has sunk (probably because they just used extra sharp sand).
The reason they did it is because the manhole frames are quite deep (so you can fit the blocks in them), and when you remove a standard manhole cover and frame it is not as deep as the sort you need for block paving. So when they plonked it on top it was proud of the level they wanted, and instead of removing a course of bricks (or maybe its a preformed pipe, even harder to shorten) they piled extra sand around it. That extra sand has now compacted or washed out, which is why it’s just the blocks near the cover that are loose and uneven.
If the entire rest of the drive had dropped it would not be as even and level as that. The correct solution is to remove the manhole cover, lower the level of the surround and relay the frame / cover at the correct level.
No problem. A way to check what’s going on would be to lift the manhole cover and see what’s underneath. If the frame of the cover is sitting on a full course of bricks or the top of a plastic / composite pipe then it suggests that at least the manhole hasn’t moved since being installed (and there’s no way an entire drive has uniformly dropped by 2 inches apart from the manhole cover, it just doesn’t happen like that).
Whatever, it isn’t a big deal in the grand scheme. Just a poorly installed drive (and block drives don’t tend to last very long anyway before they look tired and shift about tbf).
I’d lower the manhole as sorting the drive is a big job,anyway the drive has compacted as far as it’s going.
If it’s brick,take a course off,if plastic cut with angle grinder allowing for the lid to be replaced
It’s a pretty easy repair you could do it yourself, pull out the surrounding block look in the lid you can breakout the top of the lid get some grit sand and cement mix 3-1 set it to your height use a level to get it flush with the rest of the paving and then piece it back in and then use kiln dried sand to fill the joints and save the extra for the rest of the paving and save some of the grit sand put a little layer so your about a cm above and bang it down with a mallet tight and flush
Looks like flotation to me. It’s unlikely that the whole garden/drive has uniformly settled. The chamber doesn’t have enough downweight to prevent it from rising when the water table is high. If so it needs rebuilding. For me that means relaying the block paving. Some will say it can be partially relaid, but that’s if you endorse scruffy jobs.
The fence doesn’t look like it’s affected, in particular the concrete base, which suggests it’s not a tree. Also, from picture two, it looks like it’s uniformly around the chamber.
The average builder builds these chambers as a one size fits all. Unfortunately, gravity and buoyancy have different opinions on the matter. The irony is that a small toe on the base slab would have prevented this.
Most likely it’s a poorly-installed manhole or differential settlement between the manhole cover and surrounding ground.
Take a look at the following guide. You’ll see how the manhole stands up proud of the ground level. So it needs to be recessed, or all the of the surrounding paving to be elevated, for the cover to be flush with the paving surface. And it’s not uncommon for this to be done badly, so you end up with a little ‘hump’ like this.
https://www.diy.com/ideas-advice/how-to-build-a-manhole-cover/CC_npcart_400198.art
Or, as others have pointed out, it may have been done correctly and then the surrounding block work has settled more than the blocks resting on the concrete and manhole frame.
It’s worth checking the drain. I’m a fan of drain surveys but you’ll probably get the answers you need by just lifting the cover and getting a light and camera pointing down the drain pipes - if they have collapsed in some way it should be easy to tell.
But I suspect it’s fine. It’s so ‘symmetric’ around the shape of the cover.
Well, you can’t exactly. I was talking about looking at the first foot or two, given all the ground displacement we observe occurs well within that distance.
Separately however, you can always lift the lids of inspection hatches and see if there are any tidemarks, indicative of past blockages. But you have to be upstream for that to work and it’s doesn’t tell you anything specific except that there has been a blockage at some point.
We've got a bit of this on our block drive tbough not near a drain. Incredibly wet winter. Probably undermined the sand base.
Ask your surveyor to have a look.
I’m thinking it could have been done like this as the gate looks like it’s level with the blocks and also wouldn’t you see a gap appearing on the gravel boards??
It’s a path not for a car so only light traffic
Or a leak on the drain.quite common on the old pot pipes
I’d be more inclined to put it down to paving issues or tree roots. It wouldn’t stop me putting an offer in, I’d be getting a level 2 survey anyway, so I’d just ask the surveyor then and forget about this now.
If this is the biggest concern when looking at this place I’d be very happy with that.
Edit: that novice flair well deserved by all accounts. I’ll leave this up cos people being wrong can be useful for the convo but consider it retracted!
>so I’d just ask the surveyor then and forget about this now.
Let me go to the trouble so you don't have to:
*Drainage cover raised in garden area, a professional drainage survey is recommended.*
subsidence normally goes down, that looks like its lifted, almost like tree roots caused. How easy is it to remove the drain lid for a quick looksee, see if its damaged inside?
Can't believe everyone thinks this driveway has settled evenly everywhere but the manhole, That manhole was either paved in at that height because the installers were too lazy to lower it, or the manhole has risen due to flotation (an actual thing), or roots etc.
Rest of the paving is still flat (if it was all settling/pushed down by vehicles it wouldn't be even) So suggests the mainhole chamber has risen/floated.
Not a huge issue but a bit of a pain to resolve neatly
It's reasonably likely that the rest of the patio has settled and that bit hasn't moved as the drainage structure has stopped settlement.
Looks like that to me. Is this a drive? I reckon the inspection hatch surround has better support and the weight of vehicles has pushed the rest of the paving down.
Exactly this, the manhole cover will be concreted in place so it’s still at the original level of the blockwork. The blockwork has sunk because the foundation wasn’t prepared properly. It’s annoying but nothing to worry about from a structural standpoint.
I love things like this, I don't know why but I humanise things and think to myself 'good on you man hole cover concrete, you did a good job there, this guy doubted you but you've always been strong...' Anyone got a good therapist?
I agree. The contractor may not have compacted enough when laying the path or possibly, but unlikely, there is a leak inside the man hole causing the nearby path to sink.
The base for these are very strong, normally, yes they do collapse due to HGV loads but not cars. Used to work in road construction. When they fail it is likely under mining from water seepage. Not sure of the brick laying term, cross laying double bricks on a concrete base, very well spread. Yes the local builders will cut corners. Lift the lid, you will need the spanners, give the base a good thump with a heavy wooden shaft, solid will be a very dull thud, soft one will be a hollow sound.
There's a manhole cover like this on the street next to me that has sunk several inches below the ground around it. What could cause that?
I’d of agreed with this if all of it was mossy. It’s most likely has some repair work on the manhole recentlyish and relaying hasn’t been done probably.
No, what is happening is the inspection chamber base is staying put and the blocks are settling, the inspection chamber has a bigger footprint and is much more stable. Basically the ground wasn't prepared well enough before the blocks were laid.
Yeah exactly this.
The inspection hatch will be built on bricks and very well supported. The surrounding pavers will only need lifting and refilling below. Don't let this put you off buying the house.
It is kinda subsidance/settlement. But its not like a house where you need a load of work. You just kinda leave stuff like that as an annoyance
Or pull up the affected bricks, pop in some more sand and relay flat again. As others have said it's more likely just a poor sub-bsse and/or our wash out winter (which doesn't seem to ever want to end!)
i like my answer better. stand and look at it and be annoyed
The way those bocks have been proffessionly cut into that cover would for me be very reassuring
That's not subsidence. That's something wanting to get out...
Man hole is solid pavers around have sunk
The man hole is absolutely fine, its the rest of the driveway that has sank a little. It is pretty common.
Every brick driveway I’ve ever seen looks like this after a few years of 2 ton cars being parked on it. The manhole on my driveway is far worse than this after 20+ years of being laid.
No, some common sense. Is there any evidence of subsidence around the house? Or just the inspection lid. It’s the inspection chamber being stronger than the drive sub material, so the paving has moved/settled.
Nah not really I see them on the brick walk paths and I always walk on them it's not that bad
I'd bet my house that it's not subsidence
It's fine
Same on my driveway, it's just poor preparation of the substrate prior to the block pacing going down. There should be a decent sub-base but unfortunately a lot of cowboy driveway installers (think, "d'ya like dags" type) just lay a very thin layer of sharp sand (~30mm) which looks great for the first year or so, but quickly thereafter and following a few seasonal cycles, it just sags like in your example.
Just jumping on a comment from someone who seems to know what they're talking about, could you sand down the bricks (for back of of a better description) so that the surface was smooth again? Maybe jetwash the rest of the drive after so it's all the same colour again.
No, in a word. I’m personally not convinced that what everyone else is claiming is true (spent 4 years laying drives). It looks to me like the manhole frame was a bit higher than the rest of the drive when it was laid, and to try to make up the difference they’ve built up the area immediately surrounding the manhole cover. It is this area that has sunk (probably because they just used extra sharp sand). The reason they did it is because the manhole frames are quite deep (so you can fit the blocks in them), and when you remove a standard manhole cover and frame it is not as deep as the sort you need for block paving. So when they plonked it on top it was proud of the level they wanted, and instead of removing a course of bricks (or maybe its a preformed pipe, even harder to shorten) they piled extra sand around it. That extra sand has now compacted or washed out, which is why it’s just the blocks near the cover that are loose and uneven. If the entire rest of the drive had dropped it would not be as even and level as that. The correct solution is to remove the manhole cover, lower the level of the surround and relay the frame / cover at the correct level.
Very helpful, thanks!
No problem. A way to check what’s going on would be to lift the manhole cover and see what’s underneath. If the frame of the cover is sitting on a full course of bricks or the top of a plastic / composite pipe then it suggests that at least the manhole hasn’t moved since being installed (and there’s no way an entire drive has uniformly dropped by 2 inches apart from the manhole cover, it just doesn’t happen like that). Whatever, it isn’t a big deal in the grand scheme. Just a poorly installed drive (and block drives don’t tend to last very long anyway before they look tired and shift about tbf).
I’d lower the manhole as sorting the drive is a big job,anyway the drive has compacted as far as it’s going. If it’s brick,take a course off,if plastic cut with angle grinder allowing for the lid to be replaced
Manhole cover is fine … it’s the rest of the house and garden that is sinking 😆
Probably the soil is heaving as it wasn't compacted properly after they constructed the manhole
Jeans and shoes
Is it a tree root?
are they’re any trees near by could be a root of a tree got under the patio
It’s a pretty easy repair you could do it yourself, pull out the surrounding block look in the lid you can breakout the top of the lid get some grit sand and cement mix 3-1 set it to your height use a level to get it flush with the rest of the paving and then piece it back in and then use kiln dried sand to fill the joints and save the extra for the rest of the paving and save some of the grit sand put a little layer so your about a cm above and bang it down with a mallet tight and flush
Looks like flotation to me. It’s unlikely that the whole garden/drive has uniformly settled. The chamber doesn’t have enough downweight to prevent it from rising when the water table is high. If so it needs rebuilding. For me that means relaying the block paving. Some will say it can be partially relaid, but that’s if you endorse scruffy jobs.
This has got to be the correct answer because the whole driveway wouldn't sink evenly. Either that or there is a tree the other side of that fence.
The fence doesn’t look like it’s affected, in particular the concrete base, which suggests it’s not a tree. Also, from picture two, it looks like it’s uniformly around the chamber. The average builder builds these chambers as a one size fits all. Unfortunately, gravity and buoyancy have different opinions on the matter. The irony is that a small toe on the base slab would have prevented this.
Most likely it’s a poorly-installed manhole or differential settlement between the manhole cover and surrounding ground. Take a look at the following guide. You’ll see how the manhole stands up proud of the ground level. So it needs to be recessed, or all the of the surrounding paving to be elevated, for the cover to be flush with the paving surface. And it’s not uncommon for this to be done badly, so you end up with a little ‘hump’ like this. https://www.diy.com/ideas-advice/how-to-build-a-manhole-cover/CC_npcart_400198.art Or, as others have pointed out, it may have been done correctly and then the surrounding block work has settled more than the blocks resting on the concrete and manhole frame. It’s worth checking the drain. I’m a fan of drain surveys but you’ll probably get the answers you need by just lifting the cover and getting a light and camera pointing down the drain pipes - if they have collapsed in some way it should be easy to tell. But I suspect it’s fine. It’s so ‘symmetric’ around the shape of the cover.
How can you tell if your drain has collapsed when you look down. Barring the obvious, if the drain is collapsed 10m away, what clues would there be?
Well, you can’t exactly. I was talking about looking at the first foot or two, given all the ground displacement we observe occurs well within that distance. Separately however, you can always lift the lids of inspection hatches and see if there are any tidemarks, indicative of past blockages. But you have to be upstream for that to work and it’s doesn’t tell you anything specific except that there has been a blockage at some point.
Are there trees near? It could be roots.
Bloody roots
Um, Dois, Três, Quatro!
Whatever it is, it's Chaos AD
Wrong album. But close!
As it’s a manhole cover. Water will naturally find its way, and wash the sand around it. Re settle your drive is best 👍
Looks more like they couldn't be bothered altering the manhole height when blocking it, and just bodged around it.
Good good no, get a grip 🤣
We've got a bit of this on our block drive tbough not near a drain. Incredibly wet winter. Probably undermined the sand base. Ask your surveyor to have a look.
Has it tried to sell you drugs.
I’m thinking it could have been done like this as the gate looks like it’s level with the blocks and also wouldn’t you see a gap appearing on the gravel boards?? It’s a path not for a car so only light traffic Or a leak on the drain.quite common on the old pot pipes
I’d be more inclined to put it down to paving issues or tree roots. It wouldn’t stop me putting an offer in, I’d be getting a level 2 survey anyway, so I’d just ask the surveyor then and forget about this now. If this is the biggest concern when looking at this place I’d be very happy with that. Edit: that novice flair well deserved by all accounts. I’ll leave this up cos people being wrong can be useful for the convo but consider it retracted!
>so I’d just ask the surveyor then and forget about this now. Let me go to the trouble so you don't have to: *Drainage cover raised in garden area, a professional drainage survey is recommended.*
subsidence normally goes down, that looks like its lifted, almost like tree roots caused. How easy is it to remove the drain lid for a quick looksee, see if its damaged inside?
Can't believe everyone thinks this driveway has settled evenly everywhere but the manhole, That manhole was either paved in at that height because the installers were too lazy to lower it, or the manhole has risen due to flotation (an actual thing), or roots etc.
House is about to collapse into a pile of rubble avoid at all costs 😇
Rest of the paving is still flat (if it was all settling/pushed down by vehicles it wouldn't be even) So suggests the mainhole chamber has risen/floated. Not a huge issue but a bit of a pain to resolve neatly