The inevitable tree too close to house on clay soil question

[BellaB]

Hello

I’m new here, and thanks in advance

I live in WSuffolk, it’s clay, we’re atop a hill, if that’s relevant.

2 story House, walls go down 1m deep, below which is concrete in trench.  (We needed soil taken away after an oil spill elsewhere, so I saw this)  No sign of subsidence.   Previously the whole estate was a pig farm.  Maybe the odd shelter here and there, maybe some shelter trees. It wasn’t woodland. 

 

It’s been standing about 22 yrs,  now surrounded by patio, with a lean-to kit built conservatory, which sits on concrete pads, will be demolished within a year or two, it’s in an appalling state!  To be replaced by patio I expect.
 

 Patio shields soil somewhat, It’s on a bed of mortar blobs and not well pointed. Some water may get through but not all. Prior to that going in 8 yrs ago it was gravel. Next door has an original patio laid as well, and the birch roots are lifting it nearest the tree.   Both houses about 5m distant. So we’ve had a request to do something about the tree. 
 

The original owners (probably) planted trees down the boundary,( I’m sure they don’t predate the houses,)and closest to the house is a silver birch, and then a Malus, then a palm, each about  2m apart. The birch is now taller than the house. Trunk about 30cm diameter  We topped it about 6-8yrs back and it rewarded us with a spurt of growth, and two trunks instead of one!

 

We've had a tree surgeon look at it, and he advises to take it out in one go. We’ve heard about heave and that worries us, but he dismissed the idea.  He actually said taking it down gradually would stimulate the roots to grow more. What do you think of that please?  We’ve already cut it back once, as I said. 
 

We chose him because he did a balanced and attractive job of thinning a neighbour’s young trees, but I don’t know his training. He said he wasn’t insured to give a guaranteed opinion, and to inquire further, and so I’ve found you in my search. Sorry pic is rotated. Don’t know how to fix that!

Can you help please?  Many thanks

Edited July 10, 2020 by BellaB

[benedmonds]

1 hour ago, Khriss said:

@benedmonds - good - 

 

I always ask for a Structural damage report and a Soil report, often a Arb report too ( thou I often do that myself as it is Our trees they are claiming for soil shrinkage ) .

a) this weeds out the chancers who are looking for a wad to fix their shoddy extension built without Planning Permission

b) if it is a serious claim , their insurance company will actually do this ( actionable nuisance etc )

c) although nearly all claims are on London clay - a few are not - last proper claim was on a gravel substrate , the builder just did not go down the extra metre to it  ! 

d) Our trees 'might be'  causing soil shrinkage - but so are the honking great Leylandii in their next doors garden ! 

Then it gets interesting ....

 

K

But in this case there is no structal damage to the property.  The client wants to protect against the event of damage due to heave.

 

As I understand it, there is a small chance of it happening, and even if there was a high chance there is no economic solution.. You are not going to underpin a house because there "might" be a chance of heave. Therefore a survey is pointless.

 

You remove the tree in one go then fix any damage.

 

Or are there other techniques that I should be aware of..?

[Khriss]

Removing a tree which then causes heave, to yours or a neighbouring property with foreknowledge wouldnt be defendable. Hence a soil report (  which includes drains which can often be part of the issue )  Knowing wot yr house is sat on is a worthwhile cost. I am NOT saying heave WILL occur here, but cost of damage could be bitter pill if the structure has not got heave protection. Hence structural survey. Its a balancing act. Which is why i got the white sheet n rattly chains out  ? but data gives you a position to judge best course. K

[monkeybusiness]

21 minutes ago, Khriss said:

Removing a tree which then causes heave, to yours or a neighbouring property with foreknowledge wouldnt be defendable. Hence a soil report (  which includes drains which can often be part of the issue )  Knowing wot yr house is sat on is a worthwhile cost. I am NOT saying heave WILL occur here, but cost of damage could be bitter pill if the structure has not got heave protection. Hence structural survey. Its a balancing act. Which is why i got the white sheet n rattly chains out  ? but data gives you a position to judge best course. K

But there is no foreknowledge. There isn’t any history of subsidence so why would anyone need to defend their position if heave occurred at a later date following removal? It would simply become an insurance issue surely?

All a report would do is add cost and provide unnecessary work for a multitude of self-serving consultants (none of which will give a definitive answer on their own, they will all require input from consultants in other fields). 
Save a couple of grand, get it felled, move on with life. 

[Khriss]

13 hours ago, monkeybusiness said:

But there is no foreknowledge. There isn’t any history of subsidence so why would anyone need to defend their position if heave occurred at a later date following removal? It would simply become an insurance issue surely?

All a report would do is add cost and provide unnecessary work for a multitude of self-serving consultants (none of which will give a definitive answer on their own, they will all require input from consultants in other fields). 
Save a couple of grand, get it felled, move on with life. 

Which is exactly a choice you can make. But one i would not carry out without evidence. K

Edited July 13, 2020 by Khriss
( self serving consultants are sometimes well informed and accredited people who earn their living )

[daltontrees]

16 hours ago, monkeybusiness said:

All a report would do is add cost and provide unnecessary work for a multitude of self-serving consultants

Well, you've been dealing with the wrong sort of consultants. When I am advising clients I make it clear it's my job to tell them what they need to hear, not what they want to hear, and that I have no financial interest in whether there is paid tree work coming out of it or not. I alos tell them they are paying to transfer the risk to me and my insurers and that they should sue me if I get it wrong. It's not in teh slightest self-serving.

Or should the OP come on to the internet and accept the gung-ho advice of people who have never seen the tree, don't know local soil and climate conditins and (on the evidence) don't understand some of the fundamantals of shrinkable clays and certainly won't be coming forward to accept blame for uninformed actions?

Or should they accept the advice of the tree surgeon who advised to take the tree down in one go because staged removal would somehow generate more roots? Said tree surgeon could have meant well but he also stood to get a lucrative job out of it. What side of caution would a commercially-interested contractor giving out free unwritten advice fall?

I'm just going to add, asking about heave on a public website could amount to foreknowledge.

Cost of advice compared with cost of getting it wrong (with or without insurance)? Can be money well spent.

To be frank, I don't think any of us can tell enough about the circumstances to know for sure if independent advice should be bought. But this notion of self-serving consultants is I think an unhelpful distraction from choosing the right thing to do.

[Khriss]

@daltontrees put better than i did. Basically good advice, countermeasures,  fail safes,  forward planning  costs money.   Free advice.....   Well,    K

[benedmonds]

1 minute ago, Khriss said:

@daltontrees put better than i did. Basically good advice, countermeasures,  fail safes,  forward planning  costs money.   Free advice.....   Well,    K

No one has mentioned any examples of actual methods that could be used to reduce the risk of heave if removing a tree was deemed to be a high risk..  

Are there any?

You could just retain vegetation and hope it doesn't die?

Most seem to think staged removal is a waste of time as the soil will still rise the same amount. 

Has a house ever been underpinned because there is a risk of heave? 

Can you install a barrier, to ensure a soil remains in a dedicated state?

[Khriss]

59 minutes ago, benedmonds said:

No one has mentioned any examples of actual methods that could be used to reduce the risk of heave if removing a tree was deemed to be a high risk..  

Are there any?

You could just retain vegetation and hope it doesn't die?

Most seem to think staged removal is a waste of time as the soil will still rise the same amount. 

Has a house ever been underpinned because there is a risk of heave? 

Can you install a barrier, to ensure a soil remains in a dedicated state?

There are various ways to counter heave, trenching soil to give a differential in soil dessication with barrier membranes,  expanded foam lining of structures, sleeving drains and service pipes against root intrusion. And......... ! Actuly building yr house properly ( Persimmon homes take note) k

[monkeybusiness]

Self-serving was perhaps a bit strong (apologies if any consultants (self-serving or not) were offended). Obviously the incredibly important knowledge contained within the enormous brains of arboricultural consultants (and their mates who specialise in soil, and their other mates who specialise in structures) is required on many, many occasions to help guide and direct those poor souls whose limited knowledge and understanding of a particular subject may otherwise lead them into unfavourable predicaments. This in my opinion is not one of those occasions however.
I cannot in any way see a house-insurance policy refusing to pay out for heave claims if such an event occurred in the future following removal (which is absolute worst-case-scenario). There is no history of subsidence, the trees are younger than the house, the owner in no way could be seen as reckless (and subsequently liable) if they removed their trees from their garden. 
Get it felled is still my advice - I’m certain that the cost of any consultancy involvement will be significantly more than the actual cost of removal.
 

[Paul Cleaver]

On 13/07/2020 at 21:31, monkeybusiness said:

 There is no history of subsidence, the trees are younger than the house
 

Hi Dan.

In an AA journal many yrs ago these 2 key points were mentioned and the conclusion was there should be no heave - period.