Subsidence risks

(20 Posts)
purpletrees16 Sat 15-Aug-20 12:01:23

We’ve just had our full structural survey done and the surveyor recommends a structural report due to there being cracks.

I don’t mind the expense (in the scheme of a house purchase it’s all small) but I’m concerned that it’ll just be another report that tells me nothing really useful. I read it doesn’t even rule out if it’s still moving and that it will always recommend underpinning. Do I want a report that will say that? I can’t move on price (see below - weird situation).

House has no history of subsidence known to the seller or the council. It’s terraced, Victorian and was damaged during the war by a bomb that fell 100m (whole area we’re buying in is bomb damaged). Soil is right on the border of medium-high risk line and it sits on a hill. House is also decorated to a medium standard only so I feel other houses in the street may have just been replastered more recently to hide any settlement. The one visible outside crack has been repaired.

I’m torn between this being an issue that comes up with all old properties in the area
and this being a big risk.

We bid knowing the survey work value and kept bidding as I love the the house but there is another also chain free buyer who was not far away on price so we only have the discount to market that we have agreed already as they have a RICS report too.

So knowledgeable people - is this something you would do or will a survey be distinctly unhelpful since it’s not negotiation tactic just a Y/N proceed. Thanks! I’m so clueless.

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purpletrees16 Sat 15-Aug-20 21:08:00

Should say that parents have come back with conflicting advice. Gah I’ve been looking on and off for 2 years and finally found a house I like I can afford but it looks like it isn’t in great shape!

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JellyBelly78 Sat 15-Aug-20 22:39:07

My understanding is not all need underpinning at all, my husband works on houses with subsidence. The insurance company get a surveyor to monitor the cracks over a period of time to see if there is still movement. I suppose it will depend on how severe they are. He’s gone off to bed but can ask him in the morning. Anyway, it’s your insurance that pays, so assume if you’re in a susceptible area this will be more expensive.

purpletrees16 Sun 16-Aug-20 15:28:25


Thanks! That would be useful - I can post extracts from the wording and pictures if it helps.

I’m weirded out how we could be told it has no history of subsidence when we asked (and on that legal tick box form) and then the survey says it does? Because it’s London and being on a hill I did actually ask before I made the offer... so it’s been an emotionally awful weekend.

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JoJoSM2 Sun 16-Aug-20 15:44:56

I’m normally not easy put off and wouldn’t mind damp, the roof caving in etc but subsistence would seriously put me off.

JellyBelly78 Sun 16-Aug-20 18:06:14

I asked my husband and trying to remember all he said. The majority of subsidence in this country is in North London due to the clay soil and it’s not uncommon there at all. Very few need underpinning and if they do it’s because they are continuing to move.
If it’s terraced they’d all be moving and would all need underpinning.
When there’s movement an engineer comes out and checks what could be causing the cracks, for example, large tree close to house etc and this is dealt with first. They then monitor for up to 2 years and in most cases they just repair the cracks with resin or helibars and no underpinning is needed. He said it wouldn’t put him off a house. Your insurance is likely to be more expensive and perhaps more difficult to get and you’d have to pay an excess on it should there be a problem which can be high but they pay all the rest.

Whether it would have a bearing on when you resell is another matter as it could put some off if indeed it is subsidence.

Type subsidence/mumsnet into google as I’m sure this will have been covered before and might help.

purpletrees16 Sun 16-Aug-20 18:56:50

@JellyBelly78 thanks - it’s south London but it is on the wrong type of soil.

@JoJoSM2 actually the roof isn’t in great shape either but we were pre-warned on the value of work needed to be done and the roof comes under that all added in. It’s mad that it’s being rented out fine but you get a survey and apparently the chimney’s is in danger of falling off the house - poor tenants!

The issue I have is that I think the current owner (who rents it out from abroad) doesn’t think she has subsidence so doesn’t have any specialist insurance so we can’t take on a policy or anything.

I did wonder if the whole area we want to buy is either in a flood plain or clay soil - the houses are beautiful and expensive but perhaps not as expensive as they could be, I guess. We went up the hill for the lack of floodplain and got the terrible soil!

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NotMeNoNo Sun 16-Aug-20 19:01:25

The surveys/searches use some generalised maps that aren't that accurate round the edges. So they have to point it out but a more specific report would look at your actual house, trees, any soil record nearby and hopefully give you a better idea.
They should look at whether cracks are the type that suggests subsidence and how old they seem to be. The weather extremes do seem to be increasing subsidence issues in the last few years.

purpletrees16 Sun 16-Aug-20 19:20:37


The soil to left of the kitchen has “heavily subsided and is unstable”. The first paragraph on the survey is pretty hard read! There is diagonal crack from the back window and there’s damage to the plaster inside a cupboard that suggests it’s moved since they last decorated... the time passes/time I read the survey the worse it sounds.

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Dinosauraddict Sun 16-Aug-20 19:23:39

Personally this is one instance I wouldn't throw more money away on another report - there is definitely an issue there I wouldn't take on (and it takes a lot for me to walk away usually...)

NotMeNoNo Sun 16-Aug-20 23:57:01


No that's more than a bit of decorating!

NotMeNoNo Mon 17-Aug-20 00:00:58

Ok that is talking about more than shrink/swell subsidence, there sounds like some oversteepening of the hillside/slope and need for a retaining wall. Is anything about the garden different to neighbours e.g dug out to fit in a parking bay or something? A red flag as they say in Relationships.

purpletrees16 Mon 17-Aug-20 16:03:24

@NotMeNoNo front garden has been paved which may have contributed to the bay window but the main subsidence is at the back of the house next to the kitchen which is unchanged.

Seller did mention having underpinned the garden but this was sold to us as an issue to do with the topsoil wondering off...

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NotMeNoNo Mon 17-Aug-20 16:36:50

I suggest phoning the surveyor and get her/him to explain a bit more fully. To me it reads “this house is falling down the hill”. Feel free to pm me the rightmove link it would be interesting to see the lie of the land.

We’ve bought houses that need modernising, that’s one thing, but major structural issues and ground instability are totally different matter. The other buyer is probably going to knock it down!

JellyBelly78 Mon 17-Aug-20 16:38:30

It doesn’t sound like the sellers are being truthful so I’d walk away, either in denial from abroad or lying.

Dinosauraddict Tue 18-Aug-20 06:12:25

@purpletrees16 did you speak to the surveyor on the phone yesterday? They're normally a lot more forthcoming by phone.

NotMeNoNo Tue 18-Aug-20 09:42:47

Purple trees sent me a pm. I recommend talking to surveyor too. It's a nice house but sideways on a hill with the neighbouring terrace quite a bit lower, I think that's the direction of movement.

purpletrees16 Tue 18-Aug-20 22:36:44

Got the surveyor on the phone this morning and I think we’re going to have to give up on it! He estimated the works in region £100k and there’s a good chance we’d have to put the digger through the house. we’d need to do the whole cellar and the back kitchen and it’s the wrong soil for foam or any modern technique. He also said that if we left it a year it would be nearer £200k. I think the seller is going to have to use her insurance since the subsidence is new... or find someone with more equity.

Surveyor did say house has the potential to be worth it as in doing so you’d make the cellar a room with windows so you’d get a return as there’s properties worth £200k more extended on the street. Sadly as FTB on a 15% deposit we can’t ever raise that sort of cash even if the house was discounted (unless it was a third of the price which would be less than the seller bought it for over 10 years ago.)

The surveyor also said that he would advise any onward buyer to wait 15 years after underpinning to make sure that it was successful... and in his non-structural engineer opinion, the house was still on the move. We did get a mortgage, though I wonder if there’s a clause in there about declaring such stuff.

I’ve learnt the importance of checking your house for cracks!

Booked a couple of viewings at the weekend - one is promising - it’s smaller and I like the road less but it’s closer to the station and its still an adequate for us size wise. It’s been completely done up in way that’s close enough to my taste to be ok and on low risk (though not neg. risk soil). There’s nothing else on the market so we will wait and see if it doesn’t grab us. Thank you all for your help!

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purpletrees16 Tue 18-Aug-20 22:49:02

Also in-laws, who have done up a beautiful 18th c. house, said at our time of life and plans for kids anything this size of project wasn’t worth all the beautiful house in the world. They loved their house but it only worked with the kids once my MIL gave up work - and that was with a project manager - and she wasn’t sure she would make that choice again.

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House2house Tue 18-Aug-20 23:52:04

I think you must walk away from this. The vendor’s insurance should cover it and specialist insurance isn’t normally needed. But don’t make it your problem.

It does sound as if the house is slipping down the hill. DH is a Structural Engineer and stability of land can be a problem where it’s made up ground and foundations and retaining walls are insufficient for the ground conditions. The need for a retaining wall suggests the garden and house are moving. The vendor needs to deal with this because no one would get New insurance on it.

For general info, any house on a soil that shrinks (Usually due to dry conditions) can suffer from subsidence. The foundations are insufficient to support the house as the ground changes, so the house subsides. Often at the corners. Frequently this happens on clay soil and it’s not confined to London. Oxford clay does the same!

Where the ground expands, due to excessive water, its called heave. It pushes the walls of a house outwards. So you see gaps between the ceiling and the walls. Again clay in particular does this.

You can also get subsidence on gravel soils where excess water washes the gravel away causing foundations to fail. For all sorts of reasons, structural engineers monitor buildings but this one simply isn’t worth buying as the hassle factor will be immense.,

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