Conservatory wall coming away from house

[Morstonboy]

Morning all,

I'm after a bit of advice. We had a conservatory built about two years ago and have been very happy with it until the other day. I was just pottering around in there and noticed that the full height wall which border next doors property has come away from the house by 10mm at it widest point at the top. I've contacted the company who built the conservatory and they are coming round this morning to have a look. Is their anything I should be putting on the bulls*it list for when he's trying to explain this?

I've attached a picture of the gap below.

Thanks for your help
Dave

 

[joe-90]

being at the whole wall is coming away rather than just the top it suggests shrinkage rather than the conservatory floor sinking. I guess it could be your house that's moving if you are in a clay area (shrinkage and heave). Our new climate is making this a real problem if you live on clay.

 

[jeds]

Obviously a foundation problem. Do you know the following. What are your ground conditions and how deep is the foundation? Also, are there any trees nearby?

 

[HERTS P&D]

You could always check to see if your drains are all ok. This will need a cctv survey.

Andy

 

[Morstonboy]

Thanks for the replies everyone.

Our area is very clay based. You only need to go down a 10-12 inches and it's clay city.

I think the picture is slightly misleading, as the wall is worse at the top and is pretty much fine at the bottom. Their are no trees nearby, just a few bushes on the neighbours side (nothing big). The drains seem OK, no problems with flow out of the sink or anything like that.

Cheers

Dave

 

[jeds]

You need to establish how deep the foundation is. If necessary dig a hole. Very clay soils are prone to shrinkage and should be a minimum 900mm deep. If it's much less than 900 there's your problem. A lot of people think you need less than 900 for a conservatory because of the lesser load. They are wrong.

 

[noseall]

A lot of people think you need less than 900 for a conservatory because of the lesser load. They are wrong.

People directly involved with the design and build of conservatories are usually completely clueless about such things.

I have yet to see a connie foundation that i am impressed with.

Well... apart from the 1.5m thick foundation we put in for one on a slope once!

No kidding. At the shallowest end the foundations were 1.2m thick. The bungalow to which we were adjoining had foundations that were over 1.5m down from G.L. so we dug down to below these and made up with mass fill.

 

[peterperfection]

A lot of people think you need less than 900 for a conservatory because of the lesser load. They are wrong.

People directly involved with the design and build of conservatories are usually completely clueless about such things.

I have yet to see a connie foundation that i am impressed with.

Well... apart from the 1.5m thick foundation we put in for one on a slope once!

No kidding. At the shallowest end the foundations were 1.2m thick. The bungalow to which we were adjoining had foundations that were over 1.5m down from G.L. so we dug down to below these and made up with mass fill.

Well- you would be impressed with the foundations I constructed for 100s of conservatories-with 'not one single problem'.
The problem with the conservatory mentioned is because of 'cheapo foundations ' FOR SURE.
Thats why so so many conservatory companies go to the wall.
Skinny little width foundations- often only just below the soil .
Clay or no clay-- makes not much difference at all..
Ive seen it many times - and it is always INADEQUATE foundations .
Relates to difference of 'house' & extension' (conservatory) foundations.
I could write a book on it- 'really'.
The person who comes to examine the problem is sure to be on a 'loser'.
Only solution is to 'drop the wall' and start again-- probably with a bit of steel in wide strip foundations.
No other solution at all.

 

[peterperfection]

A lot of people think you need less than 900 for a conservatory because of the lesser load. They are wrong.

People directly involved with the design and build of conservatories are usually completely clueless about such things.

I have yet to see a connie foundation that i am impressed with.

Well... apart from the 1.5m thick foundation we put in for one on a slope once!

No kidding. At the shallowest end the foundations were 1.2m thick. The bungalow to which we were adjoining had foundations that were over 1.5m down from G.L. so we dug down to below these and made up with mass fill.

Well- you would be impressed with the foundations I constructed for 100s of conservatories-with 'not one single problem'.
The problem with the conservatory mentioned is because of 'cheapo foundations ' FOR SURE.
Thats why so so many conservatory companies go to the wall.
Skinny little width foundations- often only just below the soil .
Clay or no clay-- makes not much difference at all..
Ive seen it many times - and it is always INADEQUATE foundations .
Relates to difference of 'house' & extension' (conservatory) foundations.
I could write a book on it- 'really'.
The person who comes to examine the problem is sure to be on a 'loser'.
Only solution is to 'drop the wall' and start again-- probably with a bit of steel in wide strip foundations.
No other solution at all.

It's all about 'differential' movement'.
Depth of foundations dont really come into the equation--it's all about loading.
Wide strip and steel- is the only way to go.

 

[^woody^]

Depth of foundations dont really come into the equation--it's all about loading.

You will find that foundation depth has everything to do with it.

The whole purpose of a foundation is to transfer the loads down to a subsoil capable of bearing those loads - so the depth is the key factor

 

[^woody^]

.... has come away from the house by 10mm at it widest point at the top.

Seems like you've got some rotation of the foundation - basically the outer most elevation is sinking.

This is down to either inadequate foundations, which in turn could be due to one of several reasons - insufficient depth, insufficient width, incorrect type for the ground conditions etc. Or it can be a leaking drain or water main causing the ground to be wet

So its either a design/quality issue or a subsequent problem

But its more than normal shrinkage

 

[peterperfection]

Depth of foundations dont really come into the equation--it's all about loading.

You will find that foundation depth has everything to do with it.

The whole purpose of a foundation is to transfer the loads down to a subsoil capable of bearing those loads - so the depth is the key factor

Totally incorrect bud..
Always amazes me just how the inexperienced 'behind the times' builders keep digging and digging.
Depth has absolutely nothing at all to do with it.
Thats why structural engineers were born and bred---- to work it all out - and charge us plenty for the privilege of knowing just when to stop digging.
As any woman will tell you 'breadth is as good as depth .

 

[peterperfection]

.... has come away from the house by 10mm at it widest point at the top.

Seems like you've got some rotation of the foundation - basically the outer most elevation is sinking.

This is down to either inadequate foundations, which in turn could be due to one of several reasons - insufficient depth, insufficient width, incorrect type for the ground conditions etc. Or it can be a leaking drain or water main causing the ground to be wet

So its either a design/quality issue or a subsequent problem

But its more than normal shrinkage

yes- very true. I have seen it, rectified it and charged accordingly to sort it out. It's not rocket science--it's pretty easy really.
Probem for me is-- it usually happens down south. and jellied eel eaters make all the dosh and lots more-talking a good job.

 

[^woody^]

Ok, thanks for that

I'll start telling everyone not to bother with deep trenches any more, and alter all my future plans to building control accordingly. I'm sure they will be approved no problem

In fact I don't know why all but the lightest buildings have been built with deep foundations for the past 1000 years

This will save us a lot in skips, labour and concrete. Not sure about the future PI and PL claims though

Let me know when your book is published, I can't wait to get with the times

 

[jeds]

Morstonboy. Don't be confused by the bullshit. The width of a foundation for a conservatory is secondary to depth. It would most likely calculate to the width of the wall. Depth is vital when on clay because it shrinks dramatically when it dries out. Below 900 it is fairly safe because it remains permanently saturated. The beginning of this year was particularly dry and that may be why you are having problems now. You still need to find out how deep your found is.