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Original poster

Subsidence - what to expect

40 replies

SavBlancTonight · 24/04/2023 11:43

We appear to be suffering from subsidence and our insurance company is currently sending a million different specialists round on an ongoing basis to figure out why/what/how etc.

What no one seems to be able to tell me is what happens once they've decided yes, it's subsidence and it will need to be underpinned. what is involved? is it a 3 day process with a few men and a drill or is it a 3 month process and we have to move out?

Has anyone experienced this and can provide some insight?

OP posts:
TizerorFizz · 24/04/2023 13:33

They basically build a concrete raft under the house. It essentially replacing the failed foundations. It doesn’t usually require you to move out as it’s often a corner or section of the house. Not sure how long it takes but concrete is a quick job. Prep and making good take longer. Have they specifically said they are doing this? Or do you have a period of monitoring?

Original poster
SavBlancTonight · 24/04/2023 13:54

TizerorFizz · 24/04/2023 13:33

They basically build a concrete raft under the house. It essentially replacing the failed foundations. It doesn’t usually require you to move out as it’s often a corner or section of the house. Not sure how long it takes but concrete is a quick job. Prep and making good take longer. Have they specifically said they are doing this? Or do you have a period of monitoring?

Thanks. We're in a period of monitoring and people coming round every 5 minutes to figure out what the problem is. We are in a clay area which,becuase of the weird weather last year, combined with some trees on the border between our property and NDN where the roots are exacerbating the clay problem, is probably why it's happening. We believe they'll insist on removing the trees (fine) and will do this before they do anything else. Theoretically, we assume they'll also have to do the "make good" part but again, there's been no discussion on that.

It feels like they are working on it but they're not super communicative with us regarding what is likely to happen etc and how that process works.

OP posts:
MyGrandmaLizzie · 24/04/2023 14:12

@SavBlancTonight are you in the London area?
Apparently last year 8 of the top 10 areas for subsidence in England were in the London area, no doubt due to London Clay. Some areas much worse than others. Pinner more than twice as many as neighbouring Harrow for example.

TizerorFizz · 24/04/2023 14:20

@SavBlancTonight
Its not necessarily a good move to remove trees. They drink a lot of water. Where does the water go if the trees don’t need it? It stays in the soil and can cause heave. Clay soil is prone to this. I would suggest you make sure a structural engineer is advising. Insurance companies often take the cheap route out. If is possible to find a solution and keep mature trees. If they are leylandii - not worth it!!

Snowite · 24/04/2023 14:44

@TizerorFizz when you say "If they are leylandii - not worth it!!" do you mean it's not worth saving them? or that it's not worth removing them?

Sorry for my obvious ignorance! Thanks

TizerorFizz · 24/04/2023 16:16

@Snowite A bit of both! They are awful trees but have shallow roots. I always prefer a better quality deciduous tree that’s a suitable size. Who owns the trees? We have a large oak tree near our house (clay soil) but have 2m deep foundations. Trees are not evil near houses. They just require designs around their needs.

Snowite · 24/04/2023 16:32

@TizerorFizz thanks for replying. I own the trees. They're on boundary with a field and I think they were planted prior to an extension which now has external wall close to the tree line (couple metres away max). Clay soil and near a flood zoning (brook at bottom of long garden) so unsurprisingly after.last summer we had some small expansion/contraction. But the house is old (maybe 100y) and extension at least 30y old with no issues so not sure whether it's better to take those ugly trees down or whether removing them will actually destabilise the ground below.

No signs of house subsidence just a bit of wonk on the patio and a few little expansion cracks which filled in fine....I obviously need to get someone round but you sound like you know what you're talking about so thank you for any pointers 😁

TizerorFizz · 24/04/2023 16:56

@Snowite
DH is a structural Engineer and dealt with subsidence in a house owned by a family member. He’s also dealt with serious heave where trees were removed. I am not qualified but we talk and he’s acted for many people with subsidence. Just see what your insurance says. I also know that a recent extension might not have the same foundations as the house that’s older.

if the extension is newer than the trees it should have foundations agreed by Building Control to accommodate the trees. If you get rid of ugly tres, maybe replant with something more suitable or a broadleaf mixed hedge?

Snowite · 24/04/2023 17:16

Thank you so much @TizerorFizzmuch appreciated ❤️

Apols for hijacking your thread I wish you the best of luck!

Plumpciousness · 24/04/2023 17:32

Monitoring of cracks takes a year I think (to go through all the seasons). Soil samples to determine type of soil and whether tree roots are present. Maybe check the drains for cracks.

It doesn't always result in underpinning. With ours they repaired the cracks and redecorated. Removed some of the neighbours trees and water-hungry shrubs.

A neighbour had their house underpinned last year. It took weeks, if not months. I don't think they moved out.

Original poster
SavBlancTonight · 25/04/2023 10:01

MyGrandmaLizzie · 24/04/2023 14:12

@SavBlancTonight are you in the London area?
Apparently last year 8 of the top 10 areas for subsidence in England were in the London area, no doubt due to London Clay. Some areas much worse than others. Pinner more than twice as many as neighbouring Harrow for example.

London-Surrey border. And yes, every time someone turns up they tell us they're spending all their time in the broader area assessing subsidence due to clay and the recent weather.

Thanks all, this has been helpful. We know there's movement (we can see it and the first actual measurement has been taken that shows it's happening) so I am pretty sure something has to be done but it sounds like this to-ing and fro-ing is pretty normal. There are things we want to do to the house and it's so frustrating as we finally have th money, but can't do any of it becuase we're in this in between phase.

OP posts:
Oakbeam · 25/04/2023 10:07

We thought we had subsidence around twenty years ago. All the experts came out and in the end decided that it wasn’t subsidence, just “seasonal movement” and no remedial action was necessary other than redecoration.

Oakbeam · 25/04/2023 10:10

Oh, and because we had had a subsidence survey we ended up paying a fortune for our house insurance from then on despite the fact that no subsidence was found.

KievLoverTwo · 25/04/2023 10:26

Oakbeam · 25/04/2023 10:10

Oh, and because we had had a subsidence survey we ended up paying a fortune for our house insurance from then on despite the fact that no subsidence was found.

Insurance companies never cease to find a way to screw people, do they? 😡

Oakbeam · 25/04/2023 11:10

Insurance companies never cease to find a way to screw people, do they?

Indeed!

With the benefit of hindsight I would recommend that anybody who suspects subsidence gets their own survey done if possible before contacting the insurance company.

Latenightreader · 25/04/2023 11:18

It can take years to get sorted. My (generally very well thought of and not cheap) insurance company didn't send anyone round for a long while and tried to tell me what needed doing without anyone professional looking at it! It has been a battle all the way. I had a year of monitoring and tests on the roots. The work itself took three weeks: about a week to put mesh on the walls and replaster, plus they did something under the floorboards (not underpinning though), then a fortnight for the plaster to dry, then a couple of days of decorating.

I made my first report in November 2019 and I am hoping that the finally certificate will be with me soon...

Southwest12 · 25/04/2023 14:33

My old house had subsidence, South East London. The insurance monitored it for about a year, tried to drill a hole to see what was going on, and eventually said it needed underpinning.

When the skirting came off you could see how far the floors had dropped and the ground was so dry, there were 30cm deep great big cracks in it. They said all along I'd have to move out, and once they started they realised they had to underpin the front room and back room.

I was out of the house for 12 weeks. The insurance paid for a hotel. I actually got one hundreds of miles away as I could work in our office up there and there weren't many nice hotels near home. It was an apart hotel, so had cooking facilities and a laundry. Of it hadn't they'd have provided a daily allowance for food as well. It was great, the hotel had a social night 3 nights a week with free cheese and wine, and I collected enough loyalty points for 15 free nights!

Insurance redecorated everywhere with the same colour paint before I moved back in.

DevonMaman · 29/09/2023 12:38

@TizerorFizz I’m so sorry for hijacking this thread but saw you’d provided really helpful insights to OP.

I’ve recently added a new thread on potential subsidence in a house we want to purchase and am panicking - I wondered if you wouldn’t mind taking a look please?

No worries if you can’t help, I’m just desperate so thought it was worth asking! ☺️

Original poster
SavBlancTonight · 29/09/2023 12:42

@DevonMaman I do know that we've basically been told NOT to even attempt to sell our house until the subsidence is sorted and we had to remortgage during this period and couldn't go to find new mortage lenders - we had to just remortgage with te existing company. So I'd be a bit hesitant about buying a house until AFTER the subsidence is sorted. Also, our house had previous subsidence issues and it did impact our ability to insure it - we had to continue to insure it with the company who the previous owner was insured with.

The insurance company IS removing the trees - next month. I'm a bit annoyed as they are not planning to replace them with anything, even fencing, to separate our house from the NDN> They are also being extremely uncommunicative regarding steps after that. We have a "liaison" who has simply ignored all of DH's emails. We might ramp it up soon.

OP posts:
DevonMaman · 29/09/2023 12:45

@SavBlancTonight thank you so much for your response.

I feel so out of my depth with this so it’s helpful to gain some insights from people with some experience.

In our case the surveyor hasn’t actually even used the word subsidence but has said things that make me concerned that we should be getting a specialist view. I love the house and this would be the second purchase that has fallen through if we do have to pull out so I’m worried it’s my emotional (and financial) investment talking rather than my head at this point!

rwalker · 29/09/2023 12:47

I think you need to leave it a substantial length of time between the trees coming out and work starting
removing the trees will affect the ground and it will move again till it’s settled

Original poster
SavBlancTonight · 29/09/2023 12:47

Oh, so you don't have confirmed subsidence? Just a suspicion?

In which case the two things I'd be considering are

  1. If you go ahead and buy the house and it subsequently IS subsidence, will your insurance company cover it.
  2. If there's any suggestion of subsidence, I think it could be difficult as one of the questions asked is something like, "have any concerns being spotted on survey" or similar. If subsidence is one, then you'd struggle to get both a mortgage and house insurance.

I think you might need to insist on a structural engineer taking a look and if there's suspected subsidence, I am afraid that buying this house could be very tricky

OP posts:
DevonMaman · 29/09/2023 12:51

@SavBlancTonight

Yes, basically the surveyor has said he thinks the external cracks are due to a drain going wrong and has not used the word subsidence at all. I’m sorry, I don’t know how to show you my thread which has photos in it as I’m new to MN - I don’t remember the last time I went on a Forum!

This is all such a pain! I’m glad your issues are getting sorted but sorry about the trees.

hollyblueivy · 29/09/2023 12:53

Who does the tree belong to op? If the neighbour will they seek a recovery from them?

HopefulSeller · 29/09/2023 13:29

I was quite shocked a while ago when I had a property with subsidence, cracks in the walls, but it wasn’t as bad as I thought. Apparently only 20% or less (don’t quote me!) need underpinning.

Mine was due to cracked drains and they fixed it in a couple of days, and the cracks were fixed and plastered. If it’s a tree or drain, and not ground movement or foundations then that is a lot easier to fix and surely shouldn’t be more likely to happen again than other houses.