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Underpinning


Digger1
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My structural surveyor has said as a precaution i should underpin a corner of our bungalow prior to adding a first floor.  I plan to do this myself under the watchful eye of him and building control.

 

I plan to sell the property once the first floor has been added.  I see that many underpinning firms give 10-20year guarantees on their works.  Does anyone know where or how i can get insurance so i can provide a guarantee for my efforts?

 

 

 

 

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1 minute ago, Digger1 said:

My structural surveyor has said as a precaution i should underpin a corner of our bungalow prior to adding a first floor.  I plan to do this myself under the watchful eye of him and building control.

 

I plan to sell the property once the first floor has been added.  I see that many underpinning firms give 10-20year guarantees on their works.  Does anyone know where or how i can get insurance so i can provide a guarantee for my efforts?

 

 

 

 

If you want an insurance backed guarantee you need to get a specialist in.

why would an insurance company take a costly risk on your DIY work?

 

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I do hope that you can find such an insurance for your sake. But I fear that the process of of finding that insurance will be fraught with difficulty.

At the very least I suspect you will need someone who has their PII insurance of their own to sign off on the work you have done, so that he or she in turn will be able to reassure the insurance company that they are accepting a reasonable risk.

 

I really hope I'm wrong.

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8 hours ago, Digger1 said:

as a precaution i should underpin a corner of our bungalow prior to adding a first floor.

Either it needs underpinning or it doesn't.

Partial underpinning is an interesting idea, as you are undermining the building then trying to wedge it up tight again.

It is rather a primitive process, and I always thought would cause a mm or 2 of drop. For the whole building evenly that wouldn't matter, esp as it is usually because the building has already moved.

 

Not knowing the reason for the precaution, I wonder if there is another means of spreading the load away from the corner he is concerned about.

 

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Might be worth getting a second opinion. The first structural engineer advised underpinning, the second said not, if we didn't  the ground bearing slab, there was no change in the loading. BC were happy when provided with calculations and at inspection of the existing foundations. 

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It also depends on what you mean by “a corner”. If it is just 1m either side of a corner, I would just pay a specialist who can provide you with an insurance backed guarantee. Underpinning should cost about £1000 a linear metre, although it can be less if it doesn’t have to be too deep. I think I ended up paying about £650 a linear metre, although I was buying in bulk, because we did a lot! Almost two walls of my entire house. 
i think it’s the type of the thing that you either do with a professional taking on all the work or you don’t do it at all. Really not appropriate for DIY work.

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There is every reason to assume that your own work will be diligent and thorough, and possibly better than some contractors. They don't always put their best people on gutty work like this.

But I'm not confident an insurer will be excited about the business as a one-off.

 

If one Engineer says it doesn't need it, then it does seem completely precautionary by the other, or a marginal decision. Which one seems the more specialist and experienced in such works?

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11 hours ago, Digger1 said:

No.  

 

The work would be carried out according to the SE's schedule of works and overseen by building control, the exact same method as a 'specialist'.

Except that a specialist has thousands of hours of experience. How many hours’ underpinning experience do you have?

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Let me put it another way: I think @Digger1 you are putting far too much faith in the BCO. He is not going to check your concrete has been mixed to the right consistency, or that the dimensions of the blocks you are casting are the right size, or that any reinforcement bars are of the correct spec and in the correct position. Most BCOs, as far as I’m aware, don’t have any special qualifications. Some may have surveying of building backgrounds, but most don’t. They are effectively underpaid pen pushers, some are very good at what they do, but many aren’t. It’s completely luck of the draw. Maybe you are extremely confident in your ability to follow your SE’s plans and in your SE’s ability. But the fact you are enquiring about insurance suggests to me that maybe somewhere you have some doubt.

I can also say that even the best professionals make mistakes, and good teams consist of members that will spot other’s mistakes. My SE is good, occasionally a bit slow/lazy but on the whole has helped us do things I didn’t think were possible. He did however make a mistake in one of the beam designs. Luckily, my builder is very experienced and spotted the mistake before he ordered all of the beams. Who is going to spot your SE’s mistakes? Who is going to spot your mistakes? If you think it’s the BCO, then you are, to an extent, elevating your BCO to that of a project manager or site foreman, with a level of expertise that I don’t think they have. 

 

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19 minutes ago, Adsibob said:

My SE is good, occasionally a bit slow/lazy      etc...

This is now available in any Google search. I hope your alias is obscure enough.

 

But you are right on the rest. I had the misfortune to manage an underpinning process many years ago, The company had tendered and won it, never having done it before. Doing it properly was much slower than they had estimated. My boss, who knew very little, insisted it went much faster, affecting the amount undermined and the shrinking /packing process, and I moved on to a better place.

I am sure the same still happens.

 

The building inspector does not inspect often, or in close detail at all.

 

If I was an insurer I would not be interested.

 

Mr Punter is probably right though...there is no current problem (only a concern) so it is simply covered by your normal building insurance, who would then sue the builder and Engineer if there was ever a problem.

 

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@Digger1@Adsibob

…………you are putting far too much faith in the BCO. He is not going to check your concrete has been mixed to the right consistency.

Slump or cube tests will be asked for if required.

 

……….or that the dimensions of the blocks you are casting are the right size.

Yes they will.

 

……….or that any reinforcement bars are of the correct spec and in the correct position.

Yes they will. Most definitely.

 

……….Most BCOs, as far as I’m aware, don’t have any special qualifications.

You would be surprised what qualifications BCOs have.

 

……….Some may have surveying of building backgrounds, but most don’t.

Many have backgrounds in the construction industry some with specialist qualifications in architecture, engineering and construction technology.

 

……….They are effectively underpaid pen pushers.

Very naive statement - underpaid - probably - pen pushers - certainly not.

 

……….some are very good at what they do, but many aren’t.

Most are conscientious and willing to help.

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3 minutes ago, ETC said:

@Digger1@Adsibob

…………you are putting far too much faith in the BCO. He is not going to check your concrete has been mixed to the right consistency.

Slump or cube tests will be asked for if required.

 

……….or that the dimensions of the blocks you are casting are the right size.

Yes they will.

 

……….or that any reinforcement bars are of the correct spec and in the correct position.

Yes they will. Most definitely.

 

……….Most BCOs, as far as I’m aware, don’t have any special qualifications.

You would be surprised what qualifications BCOs have.

 

……….Some may have surveying of building backgrounds, but most don’t.

Many have backgrounds in the construction industry some with specialist qualifications in architecture, engineering and construction technology.

 

……….They are effectively underpaid pen pushers.

Very naive statement - underpaid - probably - pen pushers - certainly not.

 

……….some are very good at what they do, but many aren’t.

Most are conscientious and willing to help.

You are clearly more experienced than me in this and I’m sure you are right. But in my biased opinion, and I’ve only worked with four or five BCOs across three projects, two were just a pita and more concerned about irrelevant stuff than spotting important mistakes a builder had made, the third is just very laissez faire, not really worried about anything and the fourth and fifth were either very helpful or completely incompetent, depending on what mood they were in. Also had contradictory opinions on the same issue from two BCOs that worked for the same company. 
Also had some idiot BCO insist that I needed a thumb turn on a brand new front door, only for me to have to come on here to get the forum’s opinion and then quote the applicable regulations back at the BCO and ask him how he derives the interpretation that a thumb turn was required. Eventually he retracted the ridiculous position he had been taking, but not after I wasted several hours of my time learning how to do his job. So unfortunately, in my (albeit biased) experience, they are closer to pen pushers than qualified professionals. But I’m sure there are lots of exceptionally brilliant BCOs who are passionate about their job and dedicated to their careers. I just haven’t met any.

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1 hour ago, Adsibob said:

Let me put it another way: I think @Digger1 you are putting far too much faith in the BCO. He is not going to check your concrete has been mixed to the right consistency, or that the dimensions of the blocks you are casting are the right size, or that any reinforcement bars are of the correct spec and in the correct position. Most BCOs, as far as I’m aware, don’t have any special qualifications. Some may have surveying of building backgrounds, but most don’t. They are effectively underpaid pen pushers, some are very good at what they do, but many aren’t. It’s completely luck of the draw. Maybe you are extremely confident in your ability to follow your SE’s plans and in your SE’s ability. But the fact you are enquiring about insurance suggests to me that maybe somewhere you have some doubt.

I can also say that even the best professionals make mistakes, and good teams consist of members that will spot other’s mistakes. My SE is good, occasionally a bit slow/lazy but on the whole has helped us do things I didn’t think were possible. He did however make a mistake in one of the beam designs. Luckily, my builder is very experienced and spotted the mistake before he ordered all of the beams. Who is going to spot your SE’s mistakes? Who is going to spot your mistakes? If you think it’s the BCO, then you are, to an extent, elevating your BCO to that of a project manager or site foreman, with a level of expertise that I don’t think they have. 

 

Good points Adsibob about attaching too much responsibility / control over materials and workmanship to the BCO. I think that a lot of folk on BH place too much reliance on the BCO's.

 

It's not that they don't have competance.. it's just not their job to look after your self build (hold your hand) and the day to nuances.

 

@Adsibob"I can also say that even the best professionals make mistakes, and good teams consist of members that will spot other’s mistakes. My SE is good, occasionally a bit slow/lazy but on the whole has helped us do things I didn’t think were possible. He did however make a mistake in one of the beam designs. Luckily, my builder is very experienced and spotted the mistake before he ordered all of the beams. Who is going to spot your SE’s mistakes? Who is going to spot your mistakes? If you think it’s the BCO, then you are, to an extent, elevating your BCO to that of a project manager or site foreman, with a level of expertise that I don’t think they have. "

 

I'll  leave it at that as cannot add anything further of value to your well articulated post.

 

 

 

 

 

 

 

 

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6 minutes ago, Gus Potter said:

it's just not their job to look after your self build (hold your hand)

If it was the fee would be very much higher.

Some good BCOs are very busy dealing with problem jobs, and the deliberate cutting of quality, and so see the rest of us less often.

I give them the benefit of the doubt, and don't expect them to know everything.  They are allowed to be mistaken, but I would expect them to back down when necessary.

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Thanks for the advice so far.  

 

I will be talking to a mortgage broker, estate agent and solicitor to see each of their opinions on the matter.

 

In the meantime if anyone knows of an established underpinning co that provides an insurance backed guarantee in the Surrey area please let me know.

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None can give an opinion - only an engineer. 

 

I agree in principle with the earlier post, partial underpinning is unusual and not typically a good idea. But I don't know the other issues and situation so can't comment further. 

 

Look up the ASUC members (Association of Specialist Underpinning Contractors) - obviously most will be too larger for a domestic job but that'd be my first choice. If no luck there then most groundsworker contractors can underpin, but you'll want some sort of insurances details and reference work. 

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Spoke to my solicitor, they advised its unlikely to be an issue when i resell providing i can evidence the work was carried out for strengthening and not subsidence.  Mortgage broker said it wouldn't be a problem providing the solicitor confirmed the above.  

 

Spoke to my home insurance co and they said because the work was for strengthening and not underpinning then they didn't require to be informed, policy not effected.

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