Tree or not to tree - subsidence advice please ...

[Joedels]

Hi, I am in the middle of a 4 year + subsidence Insurance claim involving medium plasticity clay  soil and 2 x 300-350 year old TPO oak trees 13 metres from tge front of the property and  15 metres from the back of my property. 

* data monitoring started 4 years ago. 

Medium clay soil found after trial pits dug. Oak roots identified under foundations but no DNA analysis  done to ascertain which or both oak roots are under property. 

* only 1 oak tree crown reduced 3 years ago. Movement continued  after pruning 

* tree is within my property but near boundary with public highway and pedestrian and car traffic to schools further down the road. 

* Insurer initially offered £7,500 for re-decoration. No recognition of subsidence issue for first year of the Claim

* monitoring has stopped and started and been done at varying intervals over 4 years eg 2 monthly, 6 monthly, 8 monthly. 

* Insurer’s arborist 2023 said if tree couldn’t be removed then underpinning was the only  solution. Also RBT ‘unreliable’ and ‘unsafe’ 

* after Council refused removal of tree,  RBT proposed by Insurer. When challenged, Insurer’s arborist changed opinion from underpinning to RBT although nothing had changed from his opinion 9 months earlier when tree removal application was ongoing. 

* Insurer’s arborist is claiming credentials from a Arboricultual Organisation that had not been renewed as membership had not paid for. 

* independent structural engineer’s Report advised underpinning

* independent arborist advised against RBT due to: tree safety issues (anchor root damage and safety to public from tree damage), lack of acknowledgment of potential 2nd oak tree influence on subsidence, strong likelihood tree roots of 100-150 of age were under property when it was built. 

Insurer refusing underpinning and only offering RBT. 

Any advice woukd be appreciated. 

Thank you 

 

 

 

 

[Steven P]

I'm not an expert but going to add this here, maybe that will prompt someone more knowledgeable to answer?

 

350 year old oak tree

How old is the house?

When did the subsidence start occurring?

 

 

For example, if the house is say 50 years old, the tree 350 years old and the subsidence was noticed 5 years ago.... I am guessing that -something- else is the root cause (if you excuse the term), you can trim the tree as much as you like, put in root barriers and so on... but from what I have read here that might not be the cure. I am suspecting that the builder - maybe at the time following the regulations they needed to - didn't build the foundations to take the trees into account.

 

Might be you have to pay for an independent assessment, not necessarily an arborist, perhaps a structural engineer or similar for advice.

 

 

[Joedels]

Thanks for taking time to reply. The house is 125 years old so the tree was at least a semi-mature oak when the house was built ie the tree was 175-225 years old when the foundations were laid. There is an oak of the same age to the rear of the property and at the same distance which the Insurers have completely ignored.

The roots of both trees must have been well established beneath the house when the property was erected.

The independent structural engineer advised underpinning as did an independent arboriculturist. The Insurers insist a root barrier is the cure and will not budge despite lots of issues such as the safety of the tree if anchor roots are cut. The front garden tree is on my property but only 2’ from a boundary hedge with a pavement and road used by traffic to and from a large Primary and Secondary school further along the road. 

Many further advice or comments woukd be very valued. 

[Joedels]

ps cracking noticed 4 1/2 years ago. 

[Steven P]

19 hours ago, Joedels said:

ps cracking noticed 4 1/2 years ago. 

 

I'd be doubting that a 350 year old tree started affecting a 125 year old building about 5 years ago and suspect something else is going on.

[Joedels]

The house is on medium plasticity clay soil so that’s a factor too. The monitoring data data on 9 points around the property shows increasing movement up and down on 4 of the 9 points and on one point a continuous upward trend for over 3 years. It seems clear the from the graph based on that data that the house is moving in different directions at different rates. I think that the movement is a combination of the influence of trees and clay soil but the Insurance Company will only consider the one tree hence insistence on RBT.

Is there any other evidence I can gather to add to my argument for underpinning that I have missed? 

Thank you 

[Anno]

a continous upward trend could suggest other factors, tree roots expand and show seasonality changes, so should show a pattern that can be mapped across climate and weather data for the periods specified.

[Joedels]

Yes it is an ever increasing seasonal pattern on all but Point 1 which is nearest the 2 oak trees. Point 1 has been moving only upwards for over 2 years. It shows upward movement for the duration of the Claim of 17.9 mm (nearly 2 cms) so that Point nearest the trees is showing by far the  most  movement. Thank you for replying - hooe you might be able to say more now you have data. 

[GarethM]

And what are you expecting us to say ?.

 

Delete the tree or delete the house that was built too close ?.

[Joedels]

Yes it is an ever increasing seasonal pattern on all but Point 1 which is nearest the 2 oak trees. Point 1 has been moving only upwards for over 2 years. It shows upward movement for the duration of the Claim of 17.9 mm (nearly 2 cms) so that Point nearest the trees is showing by far the  most  movement. Thank you for replying - hooe you might be able to say more now you have data. 

[Joedels]

Re: GarethM - I certainly wasn’t expecting a dismissive reply. 

The arboricultual advice I have had from every source, both professional and informal over the last 4+ years has been constructive. That experience had set up expectations of polite and useful dialogue. 

I was hoping to get some shared experience or some interested advice Sarcasm isn’t helpful.