conservatory coming away from main building - help needed to answer some questions

[Peter Robinson]

Hi

I have no building experience and have been unable to get the following questions answered using the internet - I hope one or more of you experts can help me.

 

I had a conservatory built on to the side of my house with 3 walls measuring 4000m x 4000mmx4000mm. It had dwarf cavity walls all round to a height of 600mm on which were glazed units going up to roof level ; units + dwarf walls = 2600mm total height.
The roof was of polycarbonate construction. Foundations were laid to a depth of 750mm. 
The conservatory stood for 10 years with absolutely no problems.

 I recently had the roof replaced with a supalite roof and had the glazing removed from one sidewall and the 2000mm x 4000mm gap bricked up.

Within 3 months the conservatory started moving away from the main building. The builder is saying it's nothing to do with his work and the cause is trees which are a few feet away. The trees were present and mature when the first conservatory was built and obviously present when he did his work.

Although not admitting any liability, the builder sent round two young lads who dug a trench alongside the bricked up wall and poured concrete in and said that it had been underpinned. The conservatory continues to move from the house.

I am considering legal action against the builder as I think the extra weight of the roof and bricked up window were too much for the existing foundations. I have started researching the matter but cannot get definitive answers to some questions from the internet - theses are;

1. Should the builder have checked the existing foundations before increasing the load on them?
2. The builder used an approved inspector (not the council building control) to sign off the work - enquiries with them show that the builder described the project as, 'fit supalite roof & associated works' - should he not have made it explicit about  bricking up a window and is 'associated works' too vague a term to use - it could mean anything.
3. Should  a structural engineer have been engaged before attempting the 'underpinning'?
4. Should building control have been informed about the underpinning?
5. Do underpinners need specialist training?
6. As the builder is blaming nearby trees should he have not raised the issue before starting work?

One last issue which doesn't involve the builder - the conservatory is in my garden which is bordered by high trees and then a 7' fence. From the street you can only see a tiny fraction of the very top of the conservatory roof. The approved inspector admits he did not enter my property to sign the job off and only viewed it from the street - surely this cannot be right?

Thanks in advance for any answers given.

[ProDave]

This is a catalogue of failures at all levels of the project.

 

The obvious fact is 8 square metres of additional brickwork is going to weigh a lot more than the same area of glazing and the original foundations have started moving under that additional load.

 

Digging a trench a pouring additional concrete alongside the foundations is not underpinning.  Underpinning is digging deeper under the foundation and pouring extra concrete underneath to make the foundations deeper, and for obvious reasons it is done in sections allowing time for each section to cure.

 

And building control seem to have been negligent not ecen entering the property to look.

 

As to who is too blame, collectively they all did it wrong.  Which one to put it right?  I don't know.

[saveasteading]

All @ProDave says is right. Except we can't know that the bco didn't enter the site.

 

If the builder thinks that was underpinning:

1 he doesn't know much

2. He seems to think he had to do something.

 

We would need photos to garner any more thoughts on this.

[Peter Robinson]

Thanks for your reply. You are of course right about the weight increase,  a quick internet search reveals supalite roofs to be 10 times heavier per sq meter than a polycarbonate roof and a back of the envelope calculation has a glazed unit with 4mm glass 8 metres squared to be about 160 kg, whilst a cavity brick wall of same dimensions, 3200Kg

[Peter Robinson]

Hi, thanks for the reply. It can be confirmed that the bco did not enter our land to certify the work because we e-mailed them to ask how they gained entry and they emailed back to say they didn't and that it was an 'external' examination only!!!!

[saveasteading]

OK but don't go thinking that is the problem. The bco does spot checks when invited. He looks at what he is invited to look at.

There must be drawings. Were the foundations mentioned?

Was the brick infill shown on the drawings?

 

Even so, a big of brick isn't going to make the foundation plummet.

 

Are there cracks in the walls? 

 

 

Q3 yes

Q4 yes

Seeing the exposed ground could have been interesting.

[Peter Robinson]

Thanks for the replies - great stuff. I would have thought bco would have to attend to issue a final certificate.

The foundations were never mentioned when builder came along to replace the roof and brick the window up.

I was confused about question 4 because on one site said that underpinning must be  reported to building control or planning permission authorised - NO EXCEPTIONS. but other sites say smaller conservatories are exempt from building regs which implies BC need not be informed, hence my confusion.

[saveasteading]

Underpinning is a complex and expensive undertaking, not done lightly. It is nearly always to overcome a problem and involving an SE.

 

[Temp]

4 hours ago, Peter Robinson said:

I recently had the roof replaced with a supalite roof and had the glazing removed from one sidewall and the 2000mm x 4000mm gap bricked up.

 

Have both side walls moved or just the one with the new higher brickwork?

 

 

[ProDave]

Pictures please?

[HughF]

Knock it down, build a proper extension..

 

I know that isn’t remotely helpful, but conservatories are really a second rate solution to the ‘I want more space’ problem.

[markc]

13 minutes ago, HughF said:

Knock it down, build a proper extension..

 

I know that isn’t remotely helpful, but conservatories are really a second rate solution to the ‘I want more space’ problem.

Or get a conservatory but call it an orangery because they are so much classier lol

on a serious note, pics please including the surrounding area. Any flood defence work been done recently if you live anywhere near a river or canal? Any major construction projects close by? Change in water table or land drainage can have a big impact on tied but independent structures