Building control consent

[brikwiti]

New to the forum, hope someone can help. I have been granted planning permission for a single storey side extension to my 1930's semi. Building control noticed that there was a public sewer in the vicinity and notified the water board who have carried out a video survey and granted build over consent (the sewer is 7.4 to 8.5 metres deep). Building control approved the plans and my builder started today. The BC Officer arrived and said that the 1metre deep footings which had been approved were not sufficient and work should stop as the footings must be taken to the invert of the drains (ie: 7.5 metres deep !!). They could also not be within 1.5 metres of the sewer which effectively means that my extension cannot be built. I have tried to do the right thing and have obtained all of the necessary approvals and cannot believe that I have run into this problem at this late stage.

Any advice as to how I should proceed? I originally applied for planning permission in February and am beginning to wish that I had moved house instead/

Thanks, Rob.

 

[noseall]

7.5 metres, METRES deep! that's as deep as a house.

this requires some serious engineering spec.

just the disturbed ground alone is going to be troublesome. it seems like a piling job to me. over to you Shytalkz.........

 

[^woody^]

LMFAO.

You have a right one there, sounds like he knows what he is on about. Good luck with the build

Either get the designer back to design something a bit more appropriate, or engage an engineer.

I'd be inclined to dig some 7.5m deep x 600mm wide trenches and invite this guys colleagues around for a look. I can't believe it

 

[Shytalkz]

Plan drawer I bet...

 

[brikwiti]

Thanks for the replies. Shytalkz can you explain your comment?

 

[Shytalkz]

Yes. I misread your post.

Unless your drawings -insofar as positioning of the sewer relative to the extension is concerned - were incorrect, then you have a BRegs approval (assuming you did it on full plans and not a notice) and a BoA, so you can go ahead with it, albeit with a need to amend the proposals.

You have done nothing wrong, it's the "system" that's gone afu on you. It happens...

Your water company have seemingly dropped a right royal boll0ck. They get very nervy about their pipes when one gets anywhere near with foundations and should have asked for foundation design details, before they gave their consent. They would not have approved standard foundations, even if the details had a note saying take down to drain invert, as they get worried about lateral movement on the pipe, so quite what has happened is a tad bemusing.

However, all is not lost: there are ways of dealing with it. But traditional foundations, or a beam and base arrangement, are totally impractical - and mahoosifly expensive - for the depths that you would need to go to, not to mention Elfin Safety risks as well.

A raft is also a no-no, as this will lead to surcharge loading of the pipe, even at that depth - not likely to be much, but, to them, a surcharge is a surcharge. So that method won't be approved. There are other factors as well which mean that a raft would not be the best solution.

That leaves piling, with high level rc beams, possibly utilising a cantilever arrangement, to keep the piles as far away from the pipe as possible, which will please them. Before you throw your hands up in horror at the likely cost of this, it will not be horrendous, although it will cost you a few more ££££s than traditional strip/trenchfill foundations. You probably won't be allowed to use percussive-type piles, because of the risk of vibrations being transferred to the pipe and damaging it. However, an augured pile method would/should be acceptable to the water company.

Obviously, I don't know the layout of your extension and where the pipe is in relation, but I will gladly take a look at it for you and give you some ideas as to how to get round it and, if you want, design and detail a scheme for you to submit (as you're new to the forum, I will point out that I am an SE - I've got illegible writing, ergo sum ).

There is always a solution, don't panic.

 

[AndrewSchofield]

(as you're new to the forum, I will point out that I am an SE - I've got illegible writing, ergo sum ).

So Shytalkz, its all SEs with bad handwriting is it? - and here i was thinking it was just the guy we use - can never read what he has written!

 

[Shytalkz]

Ah, but there is method in our practice: you can't read it, make an assumption, get it wrong, whatever it is falls down, we say "That's not what is says, silly, as any fule no", hence no liability. Industry-standard spider-on-acid-scrawl is a prerequisite .

 

[Richard C]

Ah, but there is method in our practice: you can't read it, make an assumption, get it wrong, whatever it is falls down, we say "That's not what is says, silly, as any fule no", hence no liability. Industry-standard spider-on-acid-scrawl is a prerequisite .

Architects, Solicitors, Doctors, S/E’s you can never read their handwriting, they’re all the same; gives the chance of pretending it’s been misunderstood if it all goes T/U. & here we have an actual admission of it!

 

[^woody^]

Curiously, the invoice is perfectly clear though

 

[Shytalkz]

It's a question of priority.

 

[chappers]

Curiously, the invoice is perfectly clear though

Thats why it's always typed

 

[Richard C]

Curiously, the invoice is perfectly clear though

Thats why it's always typed

& with more copies than you need!

 

[brikwiti]

Shytalkz, thanks for your advice and offer of help. Part of the problem is that nobody seems to know exactly where the 7.5 metre deep sewer is. I have not seen a drawing of its location in relation to my property or the proposed extension but believe it may run underneath the front corner of my house . The house was built in 1934 so the sewer must predate this.My drawings covered the drains which are visible (there are two manholes on the drive which presumably feed into the deep sewer). Thames Water carried out a video survey of the deep sewer before granting consent and want to carry out another video survey once the extension is complete. My concern now is that we could be held liable for any damage to the 7.5 metre deep sewer in the event of any damage from the build at an unknown and likely significant cost. At the moment we are waiting for a formal response from Building Control but I think the risk of being held liable for any damage may mean we should cut our losses and not proceed further.

 

[chappers]

I would at least establish where the actual sewr runs. Get thames water to explicitly explain to you the path of the sewer and then base your decision on that.
You can't be held responsible for them not knowing where it runs.
eg if they tell you the sewer runs to the front of your house and you go digging at the back and smash through it, there is no way you can be held responsible.
Don't give up just yet.