Tree removal close to property

[Mick Dempsey]

I did a search using ‘heave’ on thread titles.

Lots of threads talking about risk of etc. But I couldn’t find any genuine cases of it.

[Thesnarlingbadger]

It's a deciduous tree, so it only removes water from the ground when in leaf, so why is there not a massive issue with heave every autumn?

Good point. Cheers

[Thesnarlingbadger]

I did a search using ‘heave’ on thread titles.
Lots of threads talking about risk of etc. But I couldn’t find any genuine cases of it.

Maybe it’s all a myth mate.

[Macpherson]

1 hour ago, Thesnarlingbadger said:

Maybe it’s all a myth mate.

Not tree related, but a mate of mine bought a house with an out building that we converted into a workshop putting in a new concrete floor in 2 sections.

 

Before the house was bought the garden had been cheaply improved for the house sale with many tons of chips lots of which made their way into the drains and blocked them so rain had nowhere to go causing the clay ground to take up water and swell.

 

The floor we'd laid moved and was pushed up an almost unbelievable amount which in a way was lucky as it flagged up the issue and we got the drains cleared with a great deal of difficulty and sorted the problem without any other noticeable damage, but it's the clearest case of heave that I've seen.

[Mesterh]

3 hours ago, Thesnarlingbadger said:

Maybe it’s all a myth mate.

Maybe so. I've dropped many a tree due to subsidence but never been involved in or know anyone who has taken a tree out which had caused heave. I'm not saying that it doesn't happen but as Mark J said it must be extremely rare.

Besides is it even a big deal? Once the house has settled you repair it and job done. If there is potential for heave what do you do? I imagine you still take it out and then deal with the consequences. Insurances companies usually just want a quick fix.

[Mark J]

6 hours ago, skyhuck said:

But why does the soil not swell up to "full field capacity" every winter when the tree is dormant and not drawing up water or sheltering the ground and we generally get higher rainfall?

 

If you have a large tree that is desiccating the soil at 3m below ground, the odds are that it's not going to fully rehydrate each year, in fact it's likely that there will be a persistent soil moisture deficit, especially in times of drought. So now you have a soil, that would usually swell up to 100%, but because of the tree, it ranges from say, 70% of its potential in summer to  90% of its potential in winter each year. That shrink/swell ratio will stay broadly the same when someone builds a house on the land. Fast forward fifty years, you fell the tree, the soil can now expand another 10%, back to its original size. 

Edited March 12, 2022 by Mark J

[Mark J]

3 hours ago, Thesnarlingbadger said:

Maybe it’s all a myth mate.

It's not a myth, it's just pretty rare. 

[Dan Maynard]

13 hours ago, Mesterh said:

Maybe so. I've dropped many a tree due to subsidence but never been involved in or know anyone who has taken a tree out which had caused heave. I'm not saying that it doesn't happen but as Mark J said it must be extremely rare.

Besides is it even a big deal? Once the house has settled you repair it and job done. If there is potential for heave what do you do? I imagine you still take it out and then deal with the consequences. Insurances companies usually just want a quick fix.

There is a sampling problem here though, the subsidence happens beforehand so the tree surgeon sees every case. Tree surgeon has gone by the time the heave happens so unless the customer rings up just to pass on news then we are all in ignorance.

 

Builders would be the ones to ask.

 

In the end I agree though, you have to fix the buildings afterwards. If it's on the knife edge of heave then seems to be a risk of subsidence when the tree gets bigger and takes more moisture.

[Canal Navvy]

Subsidence and heave are terms related to how a clay soil acts on a man made structure, shrink and swell go on every year without anybody noticing. Railway tracks on Victorian embankments can change level seasonally by three inches and the speed restriction is just called engineering works. When a building sits on the ground it helps the shrink cycle and hinders the swell cycle, as Dr. Biddle puts it "a ratcheting effect" 

 

 

[Mesterh]

8 hours ago, Dan Maynard said:

There is a sampling problem here though, the subsidence happens beforehand so the tree surgeon sees every case. Tree surgeon has gone by the time the heave happens so unless the customer rings up just to pass on news then we are all in ignorance.

 

Builders would be the ones to ask.

 

I can see your point but I would hazard at a guess that if there was heave after the removal of trees an insurance company would soon be tapping on your shoulders. I have no clue as to what the costs are for repairing damage from heave but someone has to pay and I reckon the finger would soon find out who was responsible.

 

Anywho if a customer did raise the issue and did have concerns about heave I would point them in the direction of a consultant, just to cover my back, like.