Advice on minimising subsidence from weeping willow tree in neighbours garden

Hello, I posted a longer version of this on another forum but I thought maybe I would get better advice here.

I am writing on behalf of my elderly mum who has a problem with subsidence in her old house.

She has a very old house which seems to be built on mostly clay. Her neighbours have a weeping willow tree. A few years back she noticed lots of large cracks in the walls of her house and the surveyors inspected it and said she had subsidence. She claimed through her insurance (of which she had to pay approx £1k excess) and the insurance got builders to put scaffolding up and builders did whatever they do when subsidence has occured and the subsidence was dealt with. The subsidence was apparently caused by the weeping willow tree sucking up a lot of the rainwater and the surveyors wrote to the neighbours to ask them to regularly cut back the tree.

Forward to now. There are large cracks in my mums garden because it has not rained enough and the weeping willow is taking all the water. The neighbours have not cut back the tree this year and my mum is fed up of writing/asking them to do this and gets very stressed and tired with the whole situation.

She has spoken to the surveyor and he has said there is nothing she can do except keep her garden as wet as possible and she should water her garden regularly. My mum is on a pension and cannot afford to use so much water and if there is a drought restriction she won't be able to anyway. If the insurance are brought into it again, it will be classed as a new claim (we have checked) and she will be expected to pay a hefty excess.

She has spoken to 2 gardeners to see if they can recommend anything. One has recommended that she do NOTHING and would be wasting money if she does anything on the garden. The second gardener told her he could dig down to a certain depth, turn over the soil and change the consistency of the soil so there is less clay (and I think he suggested putting in sand?) and remove as much of the willow tree roots as he could find but he was not clear about how effective this would be and wants to charge my mum £600 for this.

She is getting very stressed and worried about the subsidence coming back (although so far there are no cracks inside the house, only very deep ones on her lawn).

Anyone with any knowledge of subsidence/gardening issues is there anything she can now do that would help? She cannot keep asking the neighbours to cut the tree back as they simply don't listen to her and the surveyors have already written twice to them.

Any advice would be greatly appreciated and apologies for the tome!

 

Hi Flakypastry & Welcome to the forum.

Now that is a bit of a nightmare.

I've just done a conversion where I had to underpin the entire property because of the surrounding tree roots.

That meant digging trenches upto 2.5 metres deep under the external walls & pouring mass concrete in, just because of neighbours lelandii:DOH:

Obviously you can't afford that,(would have cost me well over £100,000 to pay someone else to do it.

Its legal to cut branches and roots that overhang or invade your property, although they remain the property of whoevers tree it is.

 

Thanks Ziggy. Unfortunately the tree does not overhang my mum's garden :(.

 

Then it`s unlikely the tree is the cause of the problem. You say your mums house is old. That being the case, I would say the cause of the problem is more likely to be a failure of the drains. Get the surveyor to arrange for someone to put a camera in the system to check for pipe damage.

 

Hi
I had a old house built in 1929 and on clay I had cracks in the lawn that you could put a hose pipe in and it would never fill up.
I suspect its because of the clay is drying out , I know willow roots can travel along way and this is not helping as well.
I had two dry summers and the cracks in the wallS started to apear then the drains broke because of all this .
I would get a second opinion as well and not bother the gardener £600 sounds a waste of money (my opinion )

Spruce

 

Why would a cracked drain make the clay soil dry out and shrink

Its likely that the roots would exploit any cracks in drains in search of water, but that would just make the sewer back up, not make the house crack.

If that were the case, there might be cause for recompense from the tree owner but it would be difficult to prove that the roots damaged the drains and that it wasn't just cyclical shrinkage and expansion of the clay that cracked them.

If anything, a cracked drain would wet the clay and stop the tree sucking so much moisture out of the soil.

 

Would getting someone to remove as much of the clay as possible (along with as many of the roots as possible) and filling it in with sand or normal earth help at all?

The surveyors did come and view the property for a second time (after the cracks in the lawn reappeared) and they are still of the opinion that the tree has caused it.

 

Ziggy, the cracks in the soil are more likely to be caused by drought. The subsidence though is more likely to be caused by excessive moisture as a result of leaking drains.

 

Thank you for this. Can you please explain what you mean so that I can relay this information back to my mum. She did have some flooding in her cellar whenever it rained which has now been fixed but the fact that you mentioned this is interesting and maybe the two are connected.

 

Dai, excessive moisture from leaking drains causes heave, not subsidence. there has been no mention of heave here.

Only subsidence due to drought.

I don't want to cause any unnesessary problems for Flakypastry and her Mother.

 

An effective root barrier is needed.

We have used rigid plastic ones to prevent roots penetrating church foundations but its still quite a big job.

 

First off, I don't know why cutting the tree back will make any difference, it's the roots that are the problem and they will grow whether the tops cut back or not.

Secondly, as some of you are aware I've had problems with the roots of my neighbours leylandii hedge, for the second time in six years they have broken up my drains in search of water. So yes I'd be inclined to blame the tree.

The problem is, if you were able to have it removed there would be settlement damage anyway and I believe it should be removed completely even though willows are protected.

I think I'd be inclined to speak to your local council to find out where you stand with regards the possibility of getting it removed. I would also take it to a lawyer before you spend any more money and see what powers he has to deal with the situation.

 

I'm no expert by any means but two things come to mind.

How far is the tree from the house?

And, how old is the house?
Does the house have proper foundations.
I doubt they are up to modern standards.

I have clay and we get large cracks in the ground during dry weather, but the house, built in 1947, doesn't move.
I know some very old properties are built on all kinds of various dodgy footings.
Some just on what was there.

Under pinning might be the only answer if the cracks, in the walls, start appearing again.

If that is not what was done by the builders first time around.

 

Help! My House Is Falling Down - 4oD - Channel 4

Have a look at this. Watch it on pop out.

 

I disagree Ziggy, watch this. Help! My House Is Falling Down - 4oD - Channel 4