Moving a drain/sewer manhole.
Discussion
Does anyone have any experience of the costs involved in moving a sewer access hole?
I'd like to add a conservatory onto the back of the house but the manhole is in the way. Yorkshire Water have said I can't build on top of it - which is fair enough.
I only want it moving approx 15ft down my garden.
I'd like to add a conservatory onto the back of the house but the manhole is in the way. Yorkshire Water have said I can't build on top of it - which is fair enough.
I only want it moving approx 15ft down my garden.
You can build over it with the use of concrete lintels and an airtight cover.
This is the cheapest solution but personally I wouldn't want a manhole in my house (however airtight).
Open it up and have a look. If it's just a straight run then it's pretty straight forward. A tee or other junction and things get more complicated.
This is the cheapest solution but personally I wouldn't want a manhole in my house (however airtight).
Open it up and have a look. If it's just a straight run then it's pretty straight forward. A tee or other junction and things get more complicated.
We have a manhole in what is now our kitchen. It has a double skin cover and there have never been any issues other than the pipework down to the next garden becoming blocked over the years, the manhole filling up and (our builders having removed the overflow because they didn't understand what it was) flooding our foundations, both via the remains of the overflow and simply over the top of the new lintels.
The first attempt at curing the lake under the house resulted in our new builder, having determined that the water was coming off the garden as he could see water running out of the remains of the overflow and into the (now excavated) concrete floor of the sitting room, blocking off the remaining pipework and building a huge concrete barrier butted up against the foundations. In fairness, our garden is extremely wet most of the time and this did seem a plausible solution.
So we relaid the concrete sitting room floor and replaced all the old floorboards which had been ripped out and left it to dry out. All was fine until, once again, I noticed six inches of water under the suspended floor. This time you could clearly see water running out of one of the conduits which ran through the concrete floor to the air bricks.
So, they dug up the concrete floor again and this time the end of the conduit was sitting in about a foot of water at the exterior wall end. At this point, and after much scratching off heads, I suggested that looking at the manhole in the kitchen was the next move. After much shaking of heads, I persuaded the builder, and my wife, that the only way forward was to partially dismantle the fitted kitchen, rip up some of the floor tiles and access the manhole. Which we did....
And lo, the water was within six inches of the top. And very cold and very clear. We hired another pump for the manhole as the one in the sitting room was permanently on, and when the water cleared to within about six inches of the bottom, the inlet became clear. It was a sodding great pipe, at least two feet in diameter and was clearly part of a land drain system. What we couldn't see was where the water was supposed to go but eventually we drained it and saw only the top third of a nine inch pipe, right at the very bottom of the manhole.
We also saw two other outlets much higher up which, it turned out, were overflows. One of these had been intended to go into the main drain at the side of the house but didn't, as we discovered when we excavated the concrete passage. This was considered as a possible way of getting the water out but the new main drain was too high. The other overflow headed off into the garden, now via the sitting room of course, and stopped at inner edge of the exterior wall.
Our builder, in his usual laterally thoughtful way, proposed building a huge new soakaway forty feet up the garden and connecting the overflow to this. So he got the mini-digger into the garden again and dug the biggest hole you ever saw - the bloody digger disappeared in it - and made a lovely soakaway with plastic crates and membrane to stop the ingress of soil but let the water soak out, and he connected it with a a fair old drop on the pipe and it certainly did take the water out of the manhole. But the water was going into the manhole so quickly - it would fill up in about two hours at this point - that the soakaway filled up too and ceased to perform its primary function.
While this was going on Thames Water turned up and said that the small pipe at the bottom of the manhole cover didn't go anywhere or do anything and it wasn't theirs to worry about anyway. Rodding it had proved nothing, other than it went as far as the far side of the house and stopped, and was therefore presumed to be part of the old soakaway system for the back of the house. Even using a Rothenburger (?), which is a very very very long, very heavy gauge wire spring which is rotated by feeding it through a DC powered unit failed to have any effect.
However, the builders nephew didn't buy this and went to have another look at next door's - down the hill - manhole. This was seen to have about a foot of water in the bottom of it and a number of pipes running in or out of it. Our neighbour declared it to be part of the drainage sytem for the back of his house and said that all the pipes furthest from the house led to a couple of soakaways of indeterminate nature. The builders nephew didn't buy this either and brought the pump round and emptied the manhole, and then experimented with the drains to see where the pipes all led, and they all led INTO the manhole. Clearly, this didn't make sense as the water then had to go somewhere, so he got into the manhole with a shovel and started digging. Two feet later he got to the bottom and, guess what, there was another pipe at each side of the hole, one of which faced our house.
Our neighbour was adamant that this was all part of the drainage system for his house but, nonetheless, was happy for the builders nephew to try rodding the pipe which seemed to head our way. This simply proved that the pipe appeared to go to the edge of his garden and then stop at the boundary wall but, by now, the builders nephew had the bit between his teeth. Drain dye was suggested but the neighbour pooh-poohed this idea as a complete waste of time. But I bought some anyway and on Sunday afternoon I poured it into our manhole cover, which was almost empty having been pumped out again, and left nature to take its course.
Monday morning dawned grey and miserable, and that just about summed up the mood of everyone involved until we lifted the neighbour's manhole cover to see it full of bright green water. And there was the bloody answer. Our manhole does drain into his, and his then drains into the main drain down the side of his house, as evidenced by checking the water in the sewer in the street. The only issue then was unblocking the pipe between out two houses and the Rothenburger proved quite effective at this. The builders nephew had to make a very hasty exit from the manhole when he heard a large crack, swiftly followed by hundreds of gallons of water which overflowed from the manhole in a matter of minutes.
This has taken place over a three year period and we are finally back in our sitting room. The bottom of the brick piers for the floors are still damp eight months after the solution was found but the actual sub floor is now dusty and dry. The insurance paid for one wall to be replastered and a new dampcourse injected, a total contribution of £2000 thousand pounds out of a total of £15000. We have managed to save the carpet which had to rolled back for two years but have redecorated the room twice now in the same period.
So, yes, you can build over the manhole quite successfully provided you don't have a f
king dhead of a builder who doesn't understand things and who isn't interested in why the digging he has done to make the foundations reveals a lot of mysterious, but apparently, obsolete pipework.
The first attempt at curing the lake under the house resulted in our new builder, having determined that the water was coming off the garden as he could see water running out of the remains of the overflow and into the (now excavated) concrete floor of the sitting room, blocking off the remaining pipework and building a huge concrete barrier butted up against the foundations. In fairness, our garden is extremely wet most of the time and this did seem a plausible solution.
So we relaid the concrete sitting room floor and replaced all the old floorboards which had been ripped out and left it to dry out. All was fine until, once again, I noticed six inches of water under the suspended floor. This time you could clearly see water running out of one of the conduits which ran through the concrete floor to the air bricks.
So, they dug up the concrete floor again and this time the end of the conduit was sitting in about a foot of water at the exterior wall end. At this point, and after much scratching off heads, I suggested that looking at the manhole in the kitchen was the next move. After much shaking of heads, I persuaded the builder, and my wife, that the only way forward was to partially dismantle the fitted kitchen, rip up some of the floor tiles and access the manhole. Which we did....
And lo, the water was within six inches of the top. And very cold and very clear. We hired another pump for the manhole as the one in the sitting room was permanently on, and when the water cleared to within about six inches of the bottom, the inlet became clear. It was a sodding great pipe, at least two feet in diameter and was clearly part of a land drain system. What we couldn't see was where the water was supposed to go but eventually we drained it and saw only the top third of a nine inch pipe, right at the very bottom of the manhole.
We also saw two other outlets much higher up which, it turned out, were overflows. One of these had been intended to go into the main drain at the side of the house but didn't, as we discovered when we excavated the concrete passage. This was considered as a possible way of getting the water out but the new main drain was too high. The other overflow headed off into the garden, now via the sitting room of course, and stopped at inner edge of the exterior wall.
Our builder, in his usual laterally thoughtful way, proposed building a huge new soakaway forty feet up the garden and connecting the overflow to this. So he got the mini-digger into the garden again and dug the biggest hole you ever saw - the bloody digger disappeared in it - and made a lovely soakaway with plastic crates and membrane to stop the ingress of soil but let the water soak out, and he connected it with a a fair old drop on the pipe and it certainly did take the water out of the manhole. But the water was going into the manhole so quickly - it would fill up in about two hours at this point - that the soakaway filled up too and ceased to perform its primary function.
While this was going on Thames Water turned up and said that the small pipe at the bottom of the manhole cover didn't go anywhere or do anything and it wasn't theirs to worry about anyway. Rodding it had proved nothing, other than it went as far as the far side of the house and stopped, and was therefore presumed to be part of the old soakaway system for the back of the house. Even using a Rothenburger (?), which is a very very very long, very heavy gauge wire spring which is rotated by feeding it through a DC powered unit failed to have any effect.
However, the builders nephew didn't buy this and went to have another look at next door's - down the hill - manhole. This was seen to have about a foot of water in the bottom of it and a number of pipes running in or out of it. Our neighbour declared it to be part of the drainage sytem for the back of his house and said that all the pipes furthest from the house led to a couple of soakaways of indeterminate nature. The builders nephew didn't buy this either and brought the pump round and emptied the manhole, and then experimented with the drains to see where the pipes all led, and they all led INTO the manhole. Clearly, this didn't make sense as the water then had to go somewhere, so he got into the manhole with a shovel and started digging. Two feet later he got to the bottom and, guess what, there was another pipe at each side of the hole, one of which faced our house.
Our neighbour was adamant that this was all part of the drainage system for his house but, nonetheless, was happy for the builders nephew to try rodding the pipe which seemed to head our way. This simply proved that the pipe appeared to go to the edge of his garden and then stop at the boundary wall but, by now, the builders nephew had the bit between his teeth. Drain dye was suggested but the neighbour pooh-poohed this idea as a complete waste of time. But I bought some anyway and on Sunday afternoon I poured it into our manhole cover, which was almost empty having been pumped out again, and left nature to take its course.
Monday morning dawned grey and miserable, and that just about summed up the mood of everyone involved until we lifted the neighbour's manhole cover to see it full of bright green water. And there was the bloody answer. Our manhole does drain into his, and his then drains into the main drain down the side of his house, as evidenced by checking the water in the sewer in the street. The only issue then was unblocking the pipe between out two houses and the Rothenburger proved quite effective at this. The builders nephew had to make a very hasty exit from the manhole when he heard a large crack, swiftly followed by hundreds of gallons of water which overflowed from the manhole in a matter of minutes.
This has taken place over a three year period and we are finally back in our sitting room. The bottom of the brick piers for the floors are still damp eight months after the solution was found but the actual sub floor is now dusty and dry. The insurance paid for one wall to be replastered and a new dampcourse injected, a total contribution of £2000 thousand pounds out of a total of £15000. We have managed to save the carpet which had to rolled back for two years but have redecorated the room twice now in the same period.
So, yes, you can build over the manhole quite successfully provided you don't have a f
king dhead of a builder who doesn't understand things and who isn't interested in why the digging he has done to make the foundations reveals a lot of mysterious, but apparently, obsolete pipework.Edited by rlw on Thursday 15th September 21:20
We had the same problem when building a sun room to the back of the house. Our guy picked a spot a bit further up the pipe, dug a hole round it, cut a hole in the top of and fitted a saddle (?) then built the sides back up and refitted the old cover. He sealed up the old manhole and the concrete floor was laid over sealing it for ever. He didn't charge any extra and his only complaint was that building control insisted that the sides were brick built instead of the the plastic unit he was expecting to use.
rlw said:
So, yes, you can build over the manhole quite successfully provided you don't have a fking dhead of a builder who doesn't understand things and who isn't interested in why the digging he has done to make the foundations reveals a lot of mysterious, but apparently, obsolete pipework.
Hell of a story, glad you got it sorted in the end.king dhead of a builder who doesn't understand things and who isn't interested in why the digging he has done to make the foundations reveals a lot of mysterious, but apparently, obsolete pipework.Busa mav said:
You will also need to enter into a " Build Over" agreement with the water board , budget another £400 and 4 weeks or so.
Only need a building over agreement if it is a public sewerThat said, I believe there is a new thing coming out that says every drain after the connection of the second property is now deemed adopted.
Eeeh it were all different in my day when we could get a load of houses on a private drain before it connected to the adopted sewer.
If the chamber is only on your own private drain, there may be alternatives to be considered like re routing you own drainage, bit costly but not overly so. If there are other properties involved then you have a problem
Busa mav said:
Skyedriver said:
Only need a building over agreement if it is a public sewer
absolutely, thats why I mentioned it as the OP said it was a sewer.
MonkeyBusiness said:
moving a sewer access hole?
.
.
Following your excellent replies its possible that I might go the other way and build on the other side (mid terrace house) although this has surface water (ie. gutter drainpipes) on the other side.
I think you are getting confused with the terms.
If you think of a 4" (100mm) pipe as a drain and anything bigger (6" or over) as a sewer then you are on the right track.
Then these can be either foul taking kitchen waste, poo etc or surface water taking roof and paving water.
Up until recently most water authorities wouldn't adopt a 4" pipe either foul or surface water.
They would generally adopt 6" and above.
Now I know there have been changes mooted (sorry out of that line of business at the minute, used to design housing estate drainage & roads) but the only other thing I can think of was that the 1936 Water Act agreed that everything built before 1936 was adopted afte the second property was connected.
So, is the pipe 4" or 6", I don't care if its poo or rain water.?
Do the local authority or water authority not want to do anything as it's not there's?
Your deeds should show the adopted/unadopted drainage
If you think of a 4" (100mm) pipe as a drain and anything bigger (6" or over) as a sewer then you are on the right track.
Then these can be either foul taking kitchen waste, poo etc or surface water taking roof and paving water.
Up until recently most water authorities wouldn't adopt a 4" pipe either foul or surface water.
They would generally adopt 6" and above.
Now I know there have been changes mooted (sorry out of that line of business at the minute, used to design housing estate drainage & roads) but the only other thing I can think of was that the 1936 Water Act agreed that everything built before 1936 was adopted afte the second property was connected.
So, is the pipe 4" or 6", I don't care if its poo or rain water.?
Do the local authority or water authority not want to do anything as it's not there's?
Your deeds should show the adopted/unadopted drainage
A few things to consider:
Which way are the pipes running in the manhole (straight through, additional connection, or, change in direction)
If it is possible, the correct way is to construct a new chamber outside the footprint of the extension to change the direction and redirect the pipe around the new structure (with additional chambers) until it is back onto the original line. You may not have space or sufficient gradient (difference in levels) on the pipe to achieve this.
If the properties were constructed prior to January 1937 and the line serves more than one house then it will already be classed as a public sewer under the Public Health Act 1936. (and consent should be obtained from your Water Authority)
If it is a more recent property then at the moment it will be classed as a private drain (if it just serves your house) or a private sewer if other houses are connected upstream. Things are due to change on 1st October this year, private sewers and lateral connections (a pipe which serves one property where it passes through neghbouring land) will be taken over by the Water Authorities; this will lead to a whole load of new requirements for building over and diversions. (Agreements, approved contractors, etc. assuming that consent would be given.)
If it is a chamber where your just house connects you should really retain some form of access for rodding in the event of blockage, even if this is a new chamber constructed further down the line.
If it's just a straight run through, then provided you bridge any crossing of the pipe with a lintel and take the foundations down below the level of the pipe (so that no load is imposed on the pipe) then this should be acceptable.
If you do end up having to retain a chamber in your conservatory, as suggested a double sealed screw down cover will be required, you can get recessed ones that floor tiles can be fitted into to make it less obtrusive and blend into the rest of the floor; whatever you do don't carpet, or tile completely over it.
If you are going for floorboards make a trapdoor over the chamber. You can guarantee that Sod's Law will mean that even if it has never blocked before, it will as soon as you build over it.
Which way are the pipes running in the manhole (straight through, additional connection, or, change in direction)
If it is possible, the correct way is to construct a new chamber outside the footprint of the extension to change the direction and redirect the pipe around the new structure (with additional chambers) until it is back onto the original line. You may not have space or sufficient gradient (difference in levels) on the pipe to achieve this.
If the properties were constructed prior to January 1937 and the line serves more than one house then it will already be classed as a public sewer under the Public Health Act 1936. (and consent should be obtained from your Water Authority)
If it is a more recent property then at the moment it will be classed as a private drain (if it just serves your house) or a private sewer if other houses are connected upstream. Things are due to change on 1st October this year, private sewers and lateral connections (a pipe which serves one property where it passes through neghbouring land) will be taken over by the Water Authorities; this will lead to a whole load of new requirements for building over and diversions. (Agreements, approved contractors, etc. assuming that consent would be given.)
If it is a chamber where your just house connects you should really retain some form of access for rodding in the event of blockage, even if this is a new chamber constructed further down the line.
If it's just a straight run through, then provided you bridge any crossing of the pipe with a lintel and take the foundations down below the level of the pipe (so that no load is imposed on the pipe) then this should be acceptable.
If you do end up having to retain a chamber in your conservatory, as suggested a double sealed screw down cover will be required, you can get recessed ones that floor tiles can be fitted into to make it less obtrusive and blend into the rest of the floor; whatever you do don't carpet, or tile completely over it.
If you are going for floorboards make a trapdoor over the chamber. You can guarantee that Sod's Law will mean that even if it has never blocked before, it will as soon as you build over it.
[quote=SirTainlyBarkin]A few things to consider:
Public Health Act 1936. /quote]
Thats the one not Water Act as I said last night (been a long day looking after son)
Agree with most of the rest of what you said too, don't like screw down covers inside although thats what we do inside factories, hospitals etc
Public Health Act 1936. /quote]
Thats the one not Water Act as I said last night (been a long day looking after son)
Agree with most of the rest of what you said too, don't like screw down covers inside although thats what we do inside factories, hospitals etc
Size has nothing to do with sewer/drain classification.
A sewer is owned by a water authority, if it's private it's a drain regardless of what's going down it.
You have foul sewers/drains and they take waste water from toilets, sinks, showers etc.
And then you have surface water sewers/drains which take rainwater from roofs and hardstandings/roads.
Regarding building over it, if it's a private drain then you can build over it by using a double sealed bolt down cover and ensuring that foundations are bridged over the pipes.
If it's a sewer then you'll need either a build over agreement with the authority that own the system, or you can apple to divert the pipe using section 185 of the water act. It's about £250 to apply for an S185, and unless you can prove that no diversion is possible then in all likelihood this is what will be required as they tend not to want their pipes built over.
A sewer is owned by a water authority, if it's private it's a drain regardless of what's going down it.
You have foul sewers/drains and they take waste water from toilets, sinks, showers etc.
And then you have surface water sewers/drains which take rainwater from roofs and hardstandings/roads.
Regarding building over it, if it's a private drain then you can build over it by using a double sealed bolt down cover and ensuring that foundations are bridged over the pipes.
If it's a sewer then you'll need either a build over agreement with the authority that own the system, or you can apple to divert the pipe using section 185 of the water act. It's about £250 to apply for an S185, and unless you can prove that no diversion is possible then in all likelihood this is what will be required as they tend not to want their pipes built over.
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