New inspection chamber... in the lounge?!!

[Lobster]

I currently have an architect working for me on my latest project, which is a proposed chopping up a of corner terrace house into two, for resale. We've been humming and ha'ing about what to do with the soil pipes for the two properties, given that in one of the two, this will need installing from scratch.

Architect's proposed solution is to dig a trench more-or-less diagonally across the solid floor of the two properties, into which we bury the sewage pipe, to intercept with an inspection chamber in the back yard. Hmm. Furthermore, this proposal would necessitate having an airtight inspection chamber actually in the lounge of house B, into which enters the soil stacks (both fully internal) from both house B and house A. So if house A has a blockage, they'd need to ask the occupant of house B to lift his lounge carpet and do the needful in the inspection chamber. (FYI house A has no direct access to the back yard, so the alternative would be dig forwards into the street, which I'm advised this would cost megabucks; and also there's no sign of any existing manholes out the front either).

It sounds mind-boggling to me that this scheme would be allowed by building control; but architect - who I have to admit is very experienced - says that apparently although they don't much like it, it's perfectly permissible. And way cheaper than the alternative. I'd be grateful for comments before I next see him!

TIA David

[Owain]

"Lobster" wrote | So if house A has a blockage, they'd need to ask the | occupant of house B to lift his lounge carpet and do | the needful in the inspection chamber.

And then finding out that Numpty Householder in B has laid laminate flooring and skirtings over the chamber.

| (FYI house A | has no direct access to the back yard, so the alternative | would be dig forwards into the street, which I'm advised | this would cost megabucks; and also there's no sign of any | existing manholes out the front either).

Is it not possible to take a separate trench from house A under house B to the back yard chamber without having to have the inspection chamber and joining the two sewers?

If you are going to keep House A you should get something put in the deeds on sale of B requiring access to be kept available to the inspection chamber. That may affect the sale price or put off some buyers. If you're selling both A and B you could keep quiet and a rug over it when showing viewers round :-)

The airtight double sealed inspection covers are perfectly fine from the no smells, no bumps in the floor point of view.

Owain

[BigWallop]

Will the two properties be up and down from each other, or back and front with each other, or ?

In an upstairs / downstairs situation it is more common to have both loos in the same sort of place in both houses, and the same with the kitchen areas. This way the waste water systems run directly down through the properties and only one outward flow is needed under the lower house and out to the main sewer system.

If the houses are being separated as front and rear, then it does pose the problem of pipework running everywhere just to supply them both correctly with both incoming and outgoing water systems. So this is a bit more intricate in its design.

When both properties are side by side, then it is a good idea to run both systems as totally separate entities and have both systems running as directly to the outside as possible with breaks or accesses until they reach the outer ground traps before flowing on to the mains sewer.

To have such a system as you describe here, is to ask for more troubles than is really needed, even in any of the situations I've described above. Both properties should always be designed to be separate from each other until the systems are fully exposed on the outside of the houses. Even if this means taking the front house down and out under the floor of the rear property, and shouldn't use rodding access or inspection points until they emerge passed the walls.

The proposed system might be perfectly acceptable, but it would make an awful mess if a blockage formed within the main sewer and the waste water began rising up through the neighbours floor from the inspection pit.

[John Armstrong]

And if the blockage is just downstream from the internal inspection chamber, it fills up, and when you open it, don't fancy trying to get the carpet clean. Not to mention the problem of putting flooring down to start with.

I think the problem here is the chamber would serve both houses, so becomes a sewer. The BR approved document

states "Access points to sewers (serving more than one property) should in places where they are accessible and apparent for use in an emergency. Examples of suitable locations include, highways, public open space, unfenced front gardens, and shared or unfenced driveways." Even if you did it this way, I think there would have to be something written into the deeds to give the other houseowner right of access, which I can see being offputting to potential buyers.

[BillR]

Greedy property developer wants us to sort out his problens for nothing!

[Martin]

If I saw this as a prospective buyer I'd walk away; wouldn't you?

[Lobster]

Thanks for the advice everyone.

I should have mentioned - back and front

This does sound eminently sensible.

So maybe I run the drain for the front house (A) totally separately from the back one, run beneath the back house (B), without an internal inspection chamber. House A therefore shouldn't be a problem. But for house B; if I have an internal soil stack, against the party wall with A, I'd need to turn it through 90 deg (or a bit more than that) at ground level, and have it set off underground under the party wall, under the floor of house B, in more or less a straight line, emerging in an inspection chamber in the back yard. Sound reasonable? I'm learning all about drains just now...! would I need, or would it be possible to have, a rodding point in house B at the place where the soil stack turns? Or would it be covered from the inspection chamber?

Cheers David

[Lobster]

That's a little unfair - never considered myself as "greedy property developer". I'm very much a diy-er; I intend to most of the work on this project myself. I have a regular 9-5(?!) desk job and will be doing it all in my spare time; furthermore this is the first time I've ever bought a property to 'develop' rather than live in.

I've been posting here on-and-off for donkey's years - damnit, it was me who ran the RFD for creation of this ng in the first place! I do hope people won't object to further posts from me about this project over the coming months...!

David

[BigWallop]

Try and keep them totally separate until they both emerge from the rear of the houses. Then once you're outside you have free reign on what needs doing. Try to supply a rodding access point internally beside the loo or the sink waste systems, to stop the need for any others elsewhere on the pipework.

This is more simple than inspection pits and rodding points all over the rest of the system. If the pipes are straight and have all the correct flow rates, then you won't need a hell of a lot of access points on the pipes.

Back to the drawing board then ? :-))

[BigWallop]

I don't see you advertising any wares or creating lease contracts for the buildings development authorities, so I have no objection at all in answering your questions.

Good luck with it, I say. And I hope you get loads a money on letting or sale.

Just make sure your DIY stands up to building control inspection. :-))

[Rick Dipper]

I have an ispection chaber in the middle of my kitchen. When the drain blocked the drain rod equipment goes throught the house, and we all know where it has been before - not nice.

Your problem would appear to be that people like me would not buy either house knowing what they would have to do if the drains blocked. I reckon it would devalue both the properties.

Your other option (a total bodge) is to fit the chamber, when building inspector goes, concrete it over, then the buyer has no idea its there, you get the best of both worlds and are long gone when the new owner finds out. If I was the new owner and found out, I would not be happy.

Rick

[Tony Bryer]

I don't think it ideal, but it's what you sometimes end up with in areas of 1930's (and earlier) houses with extensions and shared drainage running along the back of the properties.

[Lobster]

Cue - Lobster emerges from his drawing board :-)

Having taken on board the comments from the group here, and having had a visit from a drains company, I've moved on a bit....

It's proving a real bummer to sort this out. Trouble is that the inspection chamber out the back is very shallow, and since the house are built on a slight slope, with the se about 6-9" lower than the front one, there's no way I can get enough fall on an underground soil pipe connecting it to the front house. I'm advised that taking it out the front onto the Queen's highway would be likely to cost 6-7K, so that's a non-starter. So... the latest plan is to fit a communal, internal soil stack built against the party wall of the two properties, which would need only a very short, separate, near-horizontal soil pipe to connect to the upstairs toilet in each house. This stack could be built into a cavity formed to the side of the chimmney breast, on the party wall, and the pipe then travels underground to the inspection chamber out back. There would be enough fall for that.

This again has the disadvantage of poo from house A travelling down a soil stack built into house B. However, I can't see any need for A to worry B about blockages as the whole horizontal run under B can be rodded from the external inspection chamber. Presumably this is the sort of arrangement which must exist in multi-occupation blocks of flats? I wouldn't have thought the stack itself would be prone to blockages would it, surely it's the horizontal runs?

Spose I could run install two separate stacks in the chimmney breast space, with two parallel soil pipes running under B to the chamber, but not sure if that would really achieve anything.

Again, comments much appreciated!

David

[BigWallop]

You will have to allow the main stack to vent air from somewhere, so is it possible to continue the stack up and out through the roof ?

[Lobster]

Oh, sure; at least that's not a problem. So do you reckon the scheme is viable?! David

[BigWallop]

Sounds great to me, but I would ask you to allow rodding access from the loo connections as well as from the outside chamber. Just a TEE with a cap end on it, to allow a rod to be inserted in that end of the system as well. You'll be amazed at how much this would help prevent having to disturb both dwellings if the unfortunate should happen.

Run with it I say.

[roger]

In article , BigWallop writes

Good advice. IME the bottom of a drop pipe is a popular place for blockages - esp if the brickie has dropped mortar down the pipe. A slow bend here [not an elbow] is a good idea too. Just fix the Air Admittance Valve in such a way that it can be taken off non-destructively.

[Lobster]

Cheers, BW. As I've been fortunate enough never to have had occasion to need drain rods; how much access room would I need to provide in line with the TEE connection by the loo? I realise that drain rods come in 3' lengths, but how much do the things bend? Or is there a coiled version of a drain rod that would do the needful if required?

TIA David