Regularisation query

[stinkyspanner]

We have got ourselves into a bit of a situation with an extension we had built under permitted development. To cut a very long and depressing story short the work was done without informing building control, and by the time we found out that we or the builder should have informed them of what was being done it was already finished or near enough.
Anyway we applied for a regularisation certificate and this is where things began to unravel badly, it turns out that the foundations are not deep enough and so it requires underpinning before they will sign it off which is fair enough.
The builder reckons he can get resin injections done and have it signed off by an approved inspector, I'm not keen on that it just sounds like another bodge. Regardless of that am I right in thinking that regularisation can only be signed off by building control, and not an approved inspector?
I know someone will suggest asking building control but they don't take phone calls and take weeks to respond. I'm hoping that there may be someone on here who knows how the system works. It's High Wycombe council if that makes a difference
Many thanks

[Equus]

stinkyspanner said:

...am I right in thinking that regularisation can only be signed off by building control, and not an approved inspector?

Yes.

stinkyspanner said:

...I know someone will suggest asking building control but they don't take phone calls and take weeks to respond.

You submit a formal (retrospective) Building Regulations application, which they then have to respond to.

But bear in mind that it is Building Control's job to tell you whether what you are proposing is acceptable or not, not to suggest alternative solutions or design it for you.

If you want a second opinion on the Builder's proposed solution (which I would suggest would be very wise indeed, in the circumstances), then you need to engage a suitably qualified Structural Engineer.

It may (albeit a long-shot) even be that a Struct Eng can provide evidence to demonstrate that the existing foundations are satisfactory as they are (eg. if they can show by testing that the ground bearing capacity is better than Building Control have assumed, or that the loads imposed upon the foundations are less).

Edited by Equus on Tuesday 22 June 14:09

[stinkyspanner]

Thank you Equus, I've actually done the regularisation application already- that was when BC asked for proof that the foundations were deep enough and a trial hoke was dug revealing that they are of inadequate depth. The builder then get a structural engineers report which said that the foundations need to be 1.8m (due to the proximity of a tree and soil type) when in fact they are 1.2 at best and at some points less.
This was when the builder, having accepted responsibility really began to squirm and is trying to find another way out.

[rustyuk]

I've seen the resin injection advertised but was like you quite suspicious. No real reason other that the company advertising it came across as snake oil merchants.

Would be good to hear the outcome if you decide to go down this route.

[Carlososos]

Feel for you op. How is it that any one in that industry doesn’t know the basics. It’s not like he was paying for the concrete you were!

[Equus]

stinkyspanner said:

I've actually done the regularisation application already- that was when BC asked for proof that the foundations were deep enough and a trial hoke was dug revealing that they are of inadequate depth. The builder then get a structural engineers report which said that the foundations need to be 1.8m (due to the proximity of a tree and soil type) when in fact they are 1.2 at best and at some points less.
This was when the builder, having accepted responsibility really began to squirm and is trying to find another way out.

Then at risk of stating the obvious, you need to comply with what the Structural Engineer is recommending.

Builders are not qualified professionals.

As I said above, Building Control is only there to say 'yes' or 'no' to what you put in front of them, not to come up with alternative design solutions or recommendations for you.

There is nothing to stop you submitting information on the builder's suggested alternative solution, however, and if they are willing to accept it, then it would be a matter for your own judgement (perhaps backed up by your Struct Eng's opinion) whether you are prepared to accept it.

Theoretically there may be alternative solutions to the tree root problem (root barriers; clay heave protection), but if they were practical in your particular situation, I'd have expected the Struct Eng. to recommend them.

I'm not a Structural Engineer myself (we have a few on here, so maybe one will chip in, in due course), but my understanding of resin injection is that it's designed to work as a remedial solution to ground that has started to move, not as a preventative measure to pre-empt damage by tree roots or associated ground heave.

Edited by Equus on Tuesday 22 June 21:28

[stinkyspanner]

Ok, thank you that's all helpful and pretty much confirms what I suspected. I just wanted some confirmation really so that Im less likely to be fobbed off by the builder.

I will update as things develop

[fuzzyyo]

The increased depth of foundation is required to get below the shrink swell zone of the tree roots in clay soil. Resin injection in residential is usually used to fill voids below compromised slabs and drives. Not heard of it used as a remedy for shallow foundations as it'll treat immediately below the concrete in areas where its been drilled, but if if doesn't penetrate far enough, the roots will just affect the soil below the resin. The resin will only treat where it can reach, hence why its usually used to fill voids, and it won't permeate through a soil mass. Unfortunately your builders have fked up. They need to carry the cost of proper underpinning.

Edited by fuzzyyo on Tuesday 22 June 22:33

[bobtail4x4]

I`m dealing with several jobs that are being built by have a go builders, the real builders are busy, so people go down the list to find someone to do the work,
one guy thought he didn`t need an oversite concrete as he was using timber joists,then forgot to put a dpc in.
another removed a chimney and ignoring the strut engs detail re beams decided to use what he knew, so put in 2 x 4x4 fence posts and nails.

lots of jobs starting where the "builder" hasn`t a clue, digging down 400mm as he has never dug deeper for a garden wall.
the existing drain is under the dig.

[stinkyspanner]

Slight update, I had a 'proper' builder come and have a look and he gave me a fairly eye watering (but not surprising) quote to sort it out and get building control sign off. I came to an arrangement with the original builder who has paid £10k towards the cost of the remedial work. It's not really enough, but I suspect he would have folded the company had it gone to court so it's about the best outcome, plus I can get the idiot out of my life..