Manhole re-benched - Is this acceptable

[Stu666]

I've been having some work done for ground movement on the home insurance. One of the recommendations of a drain survey was to re-bench/channel in a manhole on the driveway as the existing terracotta channel was cracked and leaking.

When the insurance-appointed contractors were finished (who were from out of town), they showed me their handiwork and I immediately noticed that the new channel was sitting slightly proud of the upstream pipe. I pointed this out and asked if this would be a problem and was told it would be absolutely fine and that waste would flow over it no problem.

I've inspected it in further detail today, and while I was pleased to find no backlog of turds, it does look like toilet paper and leaves are snagging on it slightly. I've also noticed that there actually appears to be a horizontal gap of approx. 1cm between the two sections, although I think the new channel is possibly sitting on a section of the old terracotta channel or pipe, as it feels like terracotta beneath it. I would estimate the base of the new channel sits proud by 1cm.

The work was done by two lads in their early 20s, nice enough guys but I got the feeling they were wanting to get home for their tea. Just thought I would query this on here as I have no idea whether this is normal or not.

 

[kp00110]

They haven't rebenched the manhole or installed a replacement piece of pipe at correct level. Looks like they have lined atop the old pipe beneath with section of modern plastic 110 pipe. I would get it redone

 

[DAZB]

Water will flow over it but it will also likely flow under it too and continue leaking out and potentially washing away any bedding or soil or whatever it is sat on and back in the day it was quite often just sand on soil. This may cause more problems down the line as you could have a collapse when the support has gone.

 

[noseall]

I've been having some work done for ground movement on the home insurance. One of the recommendations of a drain survey was to re-bench/channel in a manhole on the driveway as the existing terracotta channel was cracked and leaking.

When the insurance-appointed contractors were finished (who were from out of town), they showed me their handiwork and I immediately noticed that the new channel was sitting slightly proud of the upstream pipe. I pointed this out and asked if this would be a problem and was told it would be absolutely fine and that waste would flow over it no problem.

I've inspected it in further detail today, and while I was pleased to find no backlog of turds, it does look like toilet paper and leaves are snagging on it slightly. I've also noticed that there actually appears to be a horizontal gap of approx. 1cm between the two sections, although I think the new channel is possibly sitting on a section of the old terracotta channel or pipe, as it feels like terracotta beneath it. I would estimate the base of the new channel sits proud by 1cm.

The work was done by two lads in their early 20s, nice enough guys but I got the feeling they were wanting to get home for their tea. Just thought I would query this on here as I have no idea whether this is normal or not.

Zero effort garbage.

Theses spaces are difficult to work in, though. I spent many an hour with my 'ed in an IC - no fun. If they are deep they are impossible. Thank the lord for plastic chambers.

 

[^woody^]

No it's not acceptable. What was the defect it is meant to rectify?

 

[Stu666]

They haven't rebenched the manhole or installed a replacement piece of pipe at correct level. Looks like they have lined atop the old pipe beneath with section of modern plastic 110 pipe. I would get it redone

Can you explain in any more detail why you think they haven't rebenched it? Just so I know what I am talking about when I go back to the insurer. Thanks.

 

[Stu666]

No it's not acceptable. What was the defect it is meant to rectify?

In their own words on the survey report, "Re-bench/channel in the manhole as it is cracked."

I have attached a photo of the manhole as it looked previously, unfortunately I don't have a high-res copy as it was gleaned from their report, but gives you an idea of the condition.

 

[DAZB]

The right hand channel which directed waste into the main run has been removed up to the chamber wall so now anything that comes down there will just splurge over the mortar and build up, a problem in the pipeline (pun intended) for sure.

 

[Stu666]

The right hand channel which directed waste into the main run has been removed up to the chamber wall so now anything that comes down there will just splurge over the mortar and build up, a problem in the pipeline (pun intended) for sure.

Not sure if it makes any difference, but the right hand channel serves a single rainwater gulley, there is nothing else connected to it. I'm no expert, but I wonder if this is why they didn't replace the pipe for this section? I did observe the lad using his hand to sort of sculp a slight depression where the pipe used to be, but it doesn't really show up on the photo.

 

[DAZB]

It would still benefit from doing properly with a defined channel from the right and the benching should be smooth strong mortar allowing any water to be directed into the drain and that looks like a badly thrown render.

 

[Ivor Windybottom]

Hang on a minute... either I'm missing something, or that pipe is sloping uphill. In which case it definitely won't work. Either that or the flow is upwards in the photo, if so the side channel is pointing the wrong way.

Either way it's rubbish. There should be a minimum 1:80 (DOWNHILL!) slope on all pipes right through the system. If the chamber outlet is higher than the inlet then it's a much bigger job than re-benching - the whole lot needs digging up and all pipes re-laying.

 

[Ivor Windybottom]

After a further look at the photos, it's utter garbage, you should complain to your insurer and it definitely needs a non-cowboy to look at it. They need to stop using whoever did it completely.

The "re-benching" is basically a slop of mortar over the top of the existing surface, plus a bit of sliced open plastic pipe. It's not even all covered, if you look at the first photo, the lower half is actually the original surface shown in the third photo. You can see the difference between the upper grey colour and lower brownish, with a scraped margin between them. They've solved nothing, plus chunks of the slopped over mortar will fairly quickly flake off and cause blockages.

 

[Stu666]

Hang on a minute... either I'm missing something, or that pipe is sloping uphill. In which case it definitely won't work. Either that or the flow is upwards in the photo, if so the side channel is pointing the wrong way.

Either way it's rubbish. There should be a minimum 1:80 (DOWNHILL!) slope on all pipes right through the system. If the chamber outlet is higher than the inlet then it's a much bigger job than re-benching - the whole lot needs digging up and all pipes re-laying.

I think the angle of the photo is distorting things slightly. The flow is definitely top to bottom and there is a gentle slope. Water does in fact flow no problem, in fact better than before because it was tending to stand a little before going down the U-bend. It's just the snagging at the top of the photo that's concerning me, and from what others are saying, I was right to question this.

I will be on to the insurers tomorrow and asking them to send a different company out. I had my suspicions I might've been dealing with cowboys, this just confirms it.

 

[Ivor Windybottom]

It definitely needs re-doing, with new pipes and concrete after breaking out all the old.

It's a total botch, there's that step you're concerned about but also the downstream pipes will shortly be full of the mortar that they've skimmed over the old broken concrete to falsely make it look like they've fixed it.

 

[blup]

Do you know what the contractor charged the insurers?