Possible subsidence

[RP66]

I am in the process of buying a house and the searches have come up with the following comment:
There is within 25m of the property a moderate to high potential for natural ground subsidence.

Having had subsidence problems with a previous property, this comment sets alarm bells ringing, should I be alarmed, any comments please.

 

[^woody^]

You could say that about every house in the country that's not built on rock.

 

[Leofric]

I suppose the question is why is there a potential for natural ground subsidence ? Is it near a cliff or a steep slope ?

 

[RP66]

Ground is flat, no slopes or cliff and is surrounded by other houses, no history of problems that I am aware of, think I will ignore it.

 

[Leofric]

I would still want to know who wrote the report and why subsidence was mentioned. Wonder if insurance company will ignore it !

 

[oldbutnotdead]

You say ''searches'- do you mean that? If yes it is entirely possible that there are old mine workings or underground rivers or suchlike in the area.
You need some more detail, get back to whoever provided that fluffy statement and ask them to justify it

 

[Leofric]

Or maybe they are starting drilling for shale gas !

 

[RP66]

The searches show that In 1887 there was an unspecified shaft approx. 86mtrs from the site!
There are no indications that drilling for shale gas is likely in the area.
The searches state that:
5.9 Natural Ground Subsidence
What is the potential for natural ground subsidence* within the search area?
Moderate - High
Guidance: The natural ground subsidence rating is obtained through the evaluation of six natural ground stability hazard datasets, which are supplied by the British Geological Survey (BGS). These datasets indicate the hazard posed by the occurrence of: Swell-Shrink Clay, Landslide, Compressible Ground, Collapsible Ground, Dissolution of Soluble Rocks and Running Sand. Many factors may contribute to ground subsidence problems. For instance, significant problems can arise in conurbations underlain by clay rich bedrock, such as over clay strata in the South East of England, or South Wales. Whilst surveyors are normally aware of local problem areas, data provided by the BGS can highlight areas where a significant potential for natural ground subsidence exists and which may need particular consideration.
Where moderate - high potential is indicated, this means that there is the potential for natural ground movement to occur that may be of concern. Such ground movement could cause damage to domestic or other properties. However, properties designed, constructed and maintained in compliance with modern building regulations should be unaffected by most minor subsidence. Therefore, if thinking of buying a property in the area, you should seek professional advice from a professional property surveyor and also look at the property yourself in more detail to look for any signs of existing damage. If you already own a property in the area, and you think natural ground movement may have damaged it, you should contact your insurance company for advice. You should also take professional advice before changing the ground in any way, for example, by planting or removing trees, changing drainage or carrying out building work.
The term "Subsidence" refers to ground movement that could cause damage to foundations in domestic or other properties.

That is all the information I have, the survey states in his survey that there is no sign of movement, the house was built in 1998.

 

[oldbutnotdead]

So a tickbox on the search. Was the survey full structural or just homebuyers? It'd be worth having a root around in the local history section of your library and see what else used to be on the site- if it's been built on made ground that's not necessarily a problem but if you ever planned extending it could get expensive (piling or other pricey systems). Also get a couple of quotes to insure the place making sure you disclose that search information.

 

[RP66]

Just Homebuyers survey, I do not think we will be extending as we are downsizing, will follow your suggestion and get a couple of quotes for insurance.

Thanks for your help.

 

[KenGMac]

RP66, good evening.

The homebuyers Numpty that as posted ticked the box needs to clarify what [insurance] "Peril" is operating from the general "catch all" BCIS list of potential dangers to the property, to invoke the BCIS catch all is simply not an option, the Numpty must specify which of the adverse possibilities are threatening the property, there are a few options in the BCIS catch all??

OK I will come clean here, I work as an insurance Subsidence Specialist, OK up here in the far frozen north in Scotland,OK if I were presented with the BCIS "get out of jail free" option.I would be asking the question posed above.

Things that you can do now?

1/. Down-load the BCIS "I-Geoligy" app on to an I-Pad, pump in the Postcode and see what BCIS know about the ground below the property.

2/. Jump on to the local Authorities planning and building control portal ans see if any of the properties in the Postcode have been underpinned or had Subsidence work undertaken?

3/. OK now for the Insurance angle andyou asking in advance of purchase??
A/. By all means contact several of your preferred potential Insurers.
B/. Ask for a quote.
C/. Now for the kicker?? the Insurer by putting the Postcode into the "system" can tell instantly as to whether the area your potential property is in, is liable to Subsidence??

How do they do it?

Simple.

All major insurers feed anonymous information to the company Experian who log every Insurance claim, such as , vandal damage, car theft, car damage, property impact damage, property fires, property flooding, and [your one] potential Subsidence.

All the above claims are collated and a system that the Insurer [only] can access is the Experians databases that will tell the Insurer what "premium" to apply based on all the potential future claims based on historical claims made, including "Subsidence"

Food for thought??

Ken

 

[RP66]

Hi Ken,
Thanks for all the info will indeed put what you suggest into action.

 

[RP66]

Info received to day:

We hold information for searches for 15 years, unfortunately we have no further information than that offered in the search that we are able to provide.
Kind regards
Marina Offord
CABE Technician
Technical Support
Devon Building Control Partnership

Which does not get me very far, awaiting to hear from planning regarding any possible subsidence in the area.
I don't have an iPad but searching via PC for BCIS "I-Geolig does not seem to bring anything up, any other suggestions.

Thanks.

 

[KenGMac]

RP66

Web site you need is

https://www.bgs.ac.uk/discoveringGeology/geologyOfBritain/viewer.html

 

[RP66]

Have looked at the insurance via my present company, at present I pay £124 for contents and buildings on my 2 Bed detached bungalow taken out in Dec 2018.
Today they would require £197.32 for the same bungalow!
Using details of the house I am hoping to buy they seem to quote the same £197.32
Searching via moneysupermarket I can get the same insurance from the same company for the new home for £126.20.
Not sure this tells me much, I assume that as the premium does not seem to change for either there is no historical problem with subsidence in the local area?