Conservatory Foundations

Postby wonky100 » Fri Apr 20, 2012 12:00 pm


Just wondering if anyone could give me any idea of how much it will cost to put some conservatory foundations right?

The conservatory is 4m x 5m approx and a surveyor has recently advised that not only are the foundations insufficient for a "normal" build as we have drains running under the conservatory that these should have been protected by putting foundations to 450mm below the drains. I've been trying to investigate repairing foundations on the internet and it looks like a trench could be dug around the perimeter to do this. The only problem is, that one of the sides is next door to our neighbour's extension so a trench can't be dug on this one side. Does anyone know what would happen here? And also, does the entire drain need to be encased? If it does, does that mean that the base will have to be dug up?

Any advice would be greatly appreciated.

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Simply Build It

Postby welsh brickie » Sat Apr 21, 2012 3:01 pm

its best to jackhammer the concrete out and start again.The surveyor is right there should be a min of 450mm of concrete under the drain and concrete lintols to bridge it.The drain only has to be encased and bridged when its under the walls your constructing.
The cost depends on how many hours the job will take, and removal of the waste.
welsh brickie
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Postby wonky100 » Mon Apr 23, 2012 7:37 am

Thanks Welsh Brickie for your response.

Unfortunately, the conservatory has been built (albeit very poorly - it wasn't a self build!), so without completely removing the structure we'd be unable to start the foundations again.
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Postby wonky100 » Tue May 08, 2012 7:09 pm

Could I ask for some more help/advice please?

The conservatory in question is subject to a dispute (county court claim issued) and the surveyor who was appointed was a single joint expert. Still haven't got the report, but despite verbally advising that the foundations weren't sufficient, as per my first post, he has now said in passing when speaking about other issues that he may "accept" the foundations as the build wasn't subject to building regs and therefore there aren't any rules about the foundations. The build has been in place for 18 mths approx and he has said that if it was going to move because of insufficient foundations then it would have moved by now.

I can understand where he's coming from but surely there are guidelines and what about my drains?

Is it ok to build on "insufficient" foundations merely because a structure isn't subject to building regs?

Views either way would be greatly appreciated.

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Joined: Fri Apr 20, 2012 11:49 am

Postby Pheiffer » Thu Feb 12, 2015 6:15 pm

Its true as your man says there are no legal requirements for compliance but just because you can do it does not mean that it is going to be safe. Your inspector has an obligation to encourage you to carry out good practice. do you know what depth the foundations are cast? as in how many inches of concrete have been cast? do you have dwarf walls?Am I right in thinking that the conservatory is up and complete already? Basically if your drain is in tact then so far so good, you may have to let sleeping dogs lay. The Conservatory Club Chippenham
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