Heave / subsidence from oak on clay soil

[joepatr]

Hi all

 

I’m based in North West London (an area with shrinkable clay subsoil) and currently have an oak tree in my garden, approx 6/7 metres tall. 

 

I’d like to have this taken down eventually but am obviously concerned about the risk of not only subsidence but also heave. 

 

Could anyone recommend the best way to manage this to ensure ensure the safety of my property? I was thinking the best way would be to have the tree slowly reduced over a period of time before having the stump totally removed. 

 

Would this be the way forward, if so, how much and over what period? I was thinking taking it down in quarters over the next few years but one of the local tree surgeons suggested thirds every couple of months. 

 

I’d be grateful for any suggestions and also any companies in the Hillingdon area who could help. 

[joepatr]

The tree is about 5 metres from the house. 

 

I havent consulted anyone yet as wasn’t quite sure who to contact / who was reputable. 

[Mick Dempsey]

Why don’t you post a photo tomorrow, when it’s light?

 

Give the experts on here something to get their teeth into.

 

 

[Squaredy]

I think you are right to be concerned.  The tree clearly has been there a long time.  The house may well have foundations not very deep.  You might get away with felling it without a thought, but it is not worth the risk.

 

Get a professional structural surveyor involved and possibly an arboriculturalist.  I would speak to the insurance company first - they may well recommend a course of action.  After all, you are trying to ensure they don't end up with a multiple thousand pound claim, so they should be very helpful.

 

My house is also built on clay and is the same vintage as yours and last year we had subsidence caused (in part) by a small apple tree.  Your risk as you say is heave not subsidence, but equally destructive.

[Gary Prentice]

Is there any history of, or evidence of, subsidence currently? I.e. Repaired cracks in the brickwork, particularly adjacent to openings such as windows and doors.

 

 

[Gary Prentice]

1 minute ago, Squaredy said:

I think you are right to be concerned.  The tree clearly has been there a long time.  The house may well have foundations not very deep.  You might get away with felling it without a thought, but it is not worth the risk.

 

Get a professional structural surveyor involved and possibly an arboriculturalist.  I would speak to the insurance company first - they may well recommend a course of action.  After all, you are trying to ensure they don't end up with a multiple thousand pound claim, so they should be very helpful.

 

My house is also built on clay and is the same vintage as yours and last year we had subsidence caused (in part) by a small apple tree.  Your risk as you say is heave not subsidence, but equally destructive.

An oak within 5m on a shrinkable clay is a definite subsidence risk. 

[benedmonds]

1 hour ago, joepatr said:

Hi guys thanks for the prompt response. 

 

The house is built in 1926, quite some time ago. I don’t know how much exactly the diameter is, I will attempt to estimate measurements later, but have attached a photo showing the bottom of said tree, but it certainly isn’t a Young tree. 

 

No damage to the house from what I can see, it’s just trying to prevent something in the future. 

Looks a lot more then 6m tall unless it has been topped just above the photo..?

Still not sure what a structural engineer will tell you...

Or what you could do if one did say heave was likely.. 

I guess you could just keep the tree.

I am happy to be corrected..

Subsidence risk is more likely then heave imo.

 

Edited January 24, 2019 by benedmonds

[Squaredy]

3 minutes ago, benedmonds said:

Looks a lot more then 6m tall unless it has been topped just above the photo..?

Still not sure what a structural engineer will tell you...

Or what you could do if one did say heave was likely.. 

I guess you could just keep the tree.

I am happy to be corrected..

Subsidence risk is more likely then heave imo.

 

Yeah maybe a catch 22.  Leave it there and perhaps get subsidence.  Remove it and possibly get heave....

[benedmonds]

Has anyone ever had a case where a tree has been felled due to subsidence only for it to then suffer from heave? 

[Mick Dempsey]

That’s certainly a lot bigger than I had imagined after you first description.

[Rough Hewn]

That trunk would be worth milling if it's not hollow.
[emoji106]