Conservatory shifting - ask to dig to check foundations

[xreyuk]

Hi,

Over the past year or so my conservatory has started shifting significantly. I've had a builder round to inspect it and he's asked me to dig a hole to check whether it was built on pilings, about a door width wide at the end of the conservatory, he has said I can dig anywhere along that wall.

My question is, how big should the hole be?

I've asked him and I can't see to get an answer out of him other than 'I'll know how deep to dig' and it needs to be about 'a door width' wide.

I've asked how far out from the wall I should go, and how far underneath the wall I should go and can't seem to get an answer out of him.

Can anyone advise?

Conservatory is about 4.5m x 3m

 

[^woody^]

A conservatory is very unlikely to have been built on piles, and if it had been it would not be moving. Are you sure this builder knows what he is talking about?

For a test hole, it needs to be as big as you are wide plus a shovel, and go down as deep as the foundation bottom, and be next to the conservatory wall.

You also need to check for drain leaks and any nearby large shrubs or trees.

Or get it looked at by a proper surveyor or engineer. The amount and type of the movement can always be a good indicator of the cause without digging.

 

[xreyuk]

Thanks.

The reason he was saying about piles, is because the surrounding estates were built on an old tip, and we're not sure if my property is on it, but it was certainly very close to it.

All of other extensions/conservatories he's built in the area, the local regs have said pilings are required, but he's unsure if my property is covered by that.

I have just found an old survey form from the previous owners when the conservatory was built, and the survey form says 'very poor ground, deeper footings than normal required'. I would assume that means it's not built on piles.

With regards to the amount of movement, the largest wall of the conservatory has separated from the property by about an inch, all the UPVC has separated in two corners, whilst the doors are difficult to lock as they are not aligned correctly.

What type of engineer should I be after, structural?

 

[Doggit]

Sounds like the house is on piles, and the conservatory on ordinary foundations. Was there planning permission for it, and did Building control sign off on the job. It might be covered by your hous insurance, and they'd seek to recover the costs from the builders.

 

[^woody^]

Structural engineer would be the person.

If as you say you have poor ground, then it may be cheaper to pull the conservatory down and build new off a suitable foundation. Piled foundations may be more costly than a conservatory.

An insurance job.

 

[chappers]

. Piled foundations may be more costly than a conservatory.

An insurance job.

Was going to say the cost of piles will probably be more than the conservatory.
Also agree it might be better to take it down anyway. There is quite clearly a serious problem any way. and again underpinning what you have will be costly and might not even be possible

 

[Notch7]

I would almost certainly a conservatory built without building regs, no problem with that as they can legitimately be exempt. However it does mean that a builder can then choose the size and depth of footing he deems required.

In reality if the house is on pilings due to being on an old tip, then the conservatory should also have been, but the cost of say 10 metre pilings would have stopped the project being viable.

I suppose it could be sitting on a raft. A strong raft would just float on the surface and would allow the top to stay fine although it would need a flexible joint with the house, as there would be differential movement.

Dig down the side of the footing and find the bottom, if its a shallow trench footing unfortunately you may have a problem. There isnt anything you can do to correct the foundation now at any sensible cost, you could unscrew all the conservatory framework, level it all up then re-fix it so it all works fine, but it could keep on moving.

 

[Dhjones]

Conservatories don't require building regs. So any movement/subsidence, is down to the builder or conservatory company to rectify under any warranty you may have with them.
On a personal note, I'd be ripping it down and have it replaced with an extension/garden room. At least you'll be able to sit in there during the summer.
Wouldn't eat your steak with a plastic knife and fork would you?