Moving an Inspection Chamber

[canofcoke]

Hello there this is a first post, so please be gentle!

I am in the process of planning an extension to my ground floor flat (Flat1) and am wondering of the possibility of moving an inspection chamber that is in the way.


There are 3 other flats above my flat in a Victorian terrace located in, London.


Flats 1,3 & 4 use an internal waste pipe that runs under the floor in my flat and flat 2 uses a separate waste pipe.


There is a single RWP that serves the whole building, both the waste and the rainwater converge in the inspection chamber, this is shown on the existing side of my sketch

Onwards from the inspection chamber the sewer runs to the adjacent property (serving them) and then connects to the main sewer.


For various reasons (mainly due to sunlight) it would be ideally located where shown on the diagram I have drawn and I am aware from Thames Water that it is unacceptable to have an inspection chamber within the property or extension.


I am wondering if (falls permitting) it is possible to move the inspection chamber to the location shown on the proposed side of my sketch, have the rainwater enter here and then have the two waste pipes connecting to the sewer beyond this point.


I have seen from Thames Waters literature (image included in post) on building over a sewer that it may be possible to move the inspection chamber out of the line of the sewer.

Any help on the above would be gratefully received, as to whether my proposals would be acceptable or if there is another method to move this inspection chamber.


Thanks


canofcoke

 

[canofcoke]

wonder if anyone was able to give any advice on this?

 

[nickjb]

Just opinion from me, no professional backing but I'd say your design would not be allowed. There is would be very limited access for a blockage in either of the two runs from the flats above and you end up with un-rodable junctions under your the extension. Is there any way to steer the left side drains directly into the inspection chamber, that would solve that side? Probably too much work, though, and will need to be done by an approved contractor. Can the external SVP from flat 2 be be run horizontally over your extension and drop down nearer the IC?

Might be best just to speak to Thames. Whatever you do will need a build over agreement.

 

[canofcoke]

Just opinion from me, no professional backing but I'd say your design would not be allowed. There is would be very limited access for a blockage in either of the two runs from the flats above and you end up with un-rodable junctions under your the extension. Is there any way to steer the left side drains directly into the inspection chamber, that would solve that side? Probably too much work, though, and will need to be done by an approved contractor. Can the external SVP from flat 2 be be run horizontally over your extension and drop down nearer the IC?

Might be best just to speak to Thames. Whatever you do will need a build over agreement.

Thanks for the reply, I think I agree with you, my thoughts are that it may well be easier to build the extension on the other side of the garden. and not build over the manhole.

 

[^woody^]

Why can't you leave it and put a sealed cover on it?

 

[canofcoke]

Why can't you leave it and put a sealed cover on it?

Because a build over agreement is required by Thames Water in order to build the extension, and inspection chambers have to be located externally from the property for access.

Should I ever need to sell the property and it doesn't have a build over agreement, this would be problematic.

Also building control will not give me a certificate without a build over agreement

This is why I can't build over it with a sealed cover, otherwise I would.

 

[^woody^]

B/S and the B/regs allow for internal sealed covers, and the water authority's build over agreement is just a private arrangement - which should be based on current industry standards and practice.

So if you can't or don't want to argue your case, and just want to accept the Thame's dictat, then you'll have to move the manhole and pipework.

 

[Nakajo]

Woody, have you argued this one out with Thames Water before?

 

[^woody^]

I don't live by that river. But the principle is the same

 

[canofcoke]

I don't live by that river. But the principle is the same

Thanks for your help, can you point me to the BS standard? And have you argued this before with another water company? Ad if so how?

 

[^woody^]

I don't know what's the current drainage standard off-hand, but its better to refer the either Approved Document H or NHBC 5.3 which are practical implementation of the standards - and they in turn are based on BS or EN standards.

The water authorities just want protection of their assets and access if need be. Any drain must conform as near as possible to any applicable standard. If this criteria is met, then there is no reason for the authority to refuse a build over agreement.

I've debated an issue a couple of times and provided technical info for another person to do some sweet talking. Its a case of showing how concerns can be met, despite veering from the published requirements. It depends on who you speak with and what level of information you can provide. You may be in for a short or long debate, but if you speak with the right person who not only knows the standards but also the potential for challenge (and their costs in answering a challenge) then things tend to work out in the homeowners favour.

The site specifics, risk of blockages, the alternatives and their costs and practicalities are all considerations to be weighed up.

But pragmatically, looking at the proposed plan, perhaps that external manhole, whilst not normally acceptable, may well be more acceptable and a better alternative to an internal manhole.

 

[canofcoke]

I don't know what's the current drainage standard off-hand, but its better to refer the either Approved Document H or NHBC 5.3 which are practical implementation of the standards - and they in turn are based on BS or EN standards.

The water authorities just want protection of their assets and access if need be. Any drain must conform as near as possible to any applicable standard. If this criteria is met, then there is no reason for the authority to refuse a build over agreement.

I've debated an issue a couple of times and provided technical info for another person to do some sweet talking. Its a case of showing how concerns can be met, despite veering from the published requirements. It depends on who you speak with and what level of information you can provide. You may be in for a short or long debate, but if you speak with the right person who not only knows the standards but also the potential for challenge (and their costs in answering a challenge) then things tend to work out in the homeowners favour.

The site specifics, risk of blockages, the alternatives and their costs and practicalities are all considerations to be weighed up.

But pragmatically, looking at the proposed plan, perhaps that external manhole, whilst not normally acceptable, may well be more acceptable and a better alternative to an internal manhole.

Woody do you advise on this sort of stuff in a professional capacity?

 

[^woody^]

Woody do you advise on this sort of stuff in a professional capacity?

Debating with statutory bodies is draining (no pun), and I would at a pinch if it's part of an existing job I was involved with, but the problem with getting involved in isolation, is that it could either be dealt with quickly, or take much longer depending on who you deal with - and personal meeting or on site discussions can be more valuable than email or phone conversations - and that is difficult when distance is involved.

Toing and froing of argument/counterargument needs to be avoided and that tends to happen unless you speak/meet with someone higher up the chain.

But you will need very good reasons about how you can meet their concerns, and if your preferred method is important to you, access to the regulations and any case law.

You really need someone local, with experience in dealing with your water authority, and who is willing to spend the time researching and arguing your case, not just accepting their first answer.

 

[noseall]

Woody do you advise on this sort of stuff in a professional capacity?

All the inmates refer to him as the 'Fixer'.