I am interested to hear of anybody with subsidence cracking. Last summer’s heatwave resulted in vast numbers of properties on clay with cracks and lots of people are having difficulties with insurers - who will only step in under limited circumstances. However, clay subsidence is usually easy to resolve.
Do you mean fix the physical problem or fix the insurance claim, when you say easy to resolve? Because as far as I know you need an arrêté de catastrophe naturelle if you want your insurance to pay for making good. And as far as buildings are concerned I imagine the only ones which might be unaffected would be tiny structures on a solid raft foundation.
I mean fix the physical problem. The vast majority of clay shrinkage subsidence is caused by roots growing underneath the foundation and shrinking the clay. It’s simply a case of checking the subsoil and removing the vegetation which is causing the problem, then repairing the cracks. Clay shrinkage rarely happens without there being a tree involved. More difficult when that tree belongs to a third party, but there are other solutions for those cases.
Welcome, Bob.
Perhaps you should declare an interest 
Have you contacted the site owners to ask about advertising your services?
I’m happy to give my input on here without charging.
Do you actually operate in France? If so then useful to add your French credentials.
That’s very kind - but you’re still offering professional services. Do you know when you will be accepted by the French authorities to practise here?
I operate worldwide, but I’m particularly interested in hearing about people’s stories of subsidence in France following last year’s hot weather and how the French insurance industry is responding to that. Clay subsidence is so easily manageable in most cases - without insurance, and I see so many clients who are unnecessarily worried about it and dont appreciate that they can easily reduce the risk themselves.
Interesting. Are you aware that old French buildings often don’t have foundations? We have a 350+ year-old property that is straight down onto clay above sandstone. There is movement all the time due to changes in the weather as the clay expands and contracts. Yes, we have cracks but I wouldn’t dream of getting in anyone to “fix it” - certainly (apologies for this) anyone who believes their UK experience is relevant. Our property has stood for many generations and no doubt will continue to do so. It doesn’t need our help. 
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We may sound a bit negative towards you, but there is a history of British registered trades/professionals causing no end of trouble for clients in France as they do not have the proper credentials and insurance. For us to employ an illegal foreign worker (which is what you would be) could result in us loosing our resident’s card. Which is catastrophic!
I’m not saying this is what you would do, but it has happened so people are very sensitive about non-registered professionals.
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Yes of course Sue, there are some old properties with insignificant foundations in the UK too, which move just the same. Its great that you are unconcerned about them, I wish many more people would be too. Unfortunately though public concern about clay subsidence in France as well as UK is increasing dramatically - you’ll see that by news articles and posts on line. Let’s hope the situation in France never reaches how it is in the UK - where properties with subsidence are almost impossible to sell (to anyone needing a mortgage to buy them).
Ah I see. I’m not looking to operate in France, just wondering how folk deal with it there and looking to raise awareness about avoiding it.
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Plenty of cracked buildings here, on clay cap over limestone with nary a tree to be seen.
It probably isn’t entirely the same in the UK and in SW France, and equally whether it’s an old building (over 300 years), a newer one (anything up to a century) or a modern one.
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I don’t think you can make direct comparisons with properties in the UK and France. Here in Normandy virtually all the rural properties exhibit movement cracks and the houses are built largely of sandstone and lime mortar without any proper foundations. Our house and that of our 4 neighbours, all exhibit movement cracks but the walls are probably getting on for 1m thick. None of the houses has trees in proximity, it is purely that they are built on clay that swells in the winter and shrinks in the summer, and the cracks close and open accordingly. None of this is of concern to most French house owners or their insurers, whereas in the UK, the houses would probably be condemned.
The argument is they have stood here for hundreds of years and will remain so for hundreds more!
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It’s the same phenomenon everywhere - just differing views of it. Of course in hotter areas and shallow foundations you get subsidence caused by more minor vegetation and in some cases just surface evaporation. I wish that more folk in the UK would have a similar attitude to the French over such matters!
My daughter’s texan house like all the others in the area, is built on a very thick pad of reinforced concrete in a 100% clay base and then the brickwork on top as normal. This base has to be insured seperately from the rest of the building as that is what is most likely to crack or move and she has a gas outlet tap on her land too from the oil wells. Every country and its constructions on clay are different and act differently too so no comparisons can really be made.
Hi Bob,
I would be interested to know how to go about figuring out what has caused subsidence in a property ?
There are 3 possible causes :
The last 3-5years of drought.
A tree growing about 5metres away from the house and is now about 25years old.
Water and waste pipes.
Your thoughts on this would be amazing. We are on a bed of clay and the house has no foundations. Its basically a converted barn with a small cottage part the same age plus a newer addition that has regrettably been made of concrete rincluing a small cellar beneath part of it.
I suspect many people will have a fight on their hands dealing with their insurer over subsidence. Our mairie (in 24) told residents that last year’s sécheresse had been recognised as a natural disaster for the commune and they should contact their insurers sharpish. In translation, the mairie said: “From the date of publication in the Official Journal, so September the 14th, 2023, you have a period of 30 days during which you can submit an estimated statement of your losses to your insurance company, in order to benefit from the compensation scheme provided for by law n°82-600 of July the 13th, 1982.” I don’t know long it takes for the effects of subsidence to show up, but thankfully my house seems to be unscathed.
Id be happy to hear from anyone with experience of this. A small correction : cracks appeared at least 8-10 years ago. Im not sure when the French droughts began but this has me thinking that the youngish tree nearby is a likely cause of this problem although the secherresse obviousely doesnt help either.
Tree roots are unfairly blamed quite often. In general they can coexist quite comfortably.