Engineering solution for wall, being pushed over by tree.

[benedmonds]

Any engineering solutions so we can save the tree.

Big beech tree with TPO.

It is in a  conservation area and the wall needs to be rebuilt looking the same..

Cannot move the wall.

The tree trunk is not in direct contact with wall. But the cracks are affecting 4-5m in the walls length.

The brick part is only 19 years old built on sandstone that was probably put down in the 1850's.

 

Consent has been given to remove the tree but one of the residents is keen to retain it if we can come up with an engineering solution that will last.

A structural engineer is having a look but in my experience they tend to look at the simplest method, which is obviously to remove the tree and rebuild the wall.  

 

My idea is to use piles and beams and to leave a good gap around the trunk.  Can you build flexible walls..

 

Edited May 15, 2019 by benedmonds

[AA Teccie (Paul)]

Wall doesn't (yet) look unstable...poly-filla and retain a while longer

 

Without the option to build into the footpath I can't readily see an engineering solution unfortunately. An alternative approach could be to remove the section of wall affected, above the inside ground level of course, and replace with fencing appen  

 

Shame, a nice tree...sorry Ben

Paul ("chocolate fireguard")

[spuddog0507]

what ever engineering solution you come up with ? it will only need doing again and again in the future, from my past expierance in this subject there is only one answer, as we can not stop the forces of nature and that tree is  only going to get bigger as time goes on and push the wall out even further and even lift the footpath, then thats another problem for the the property owner, once brick work is opened up like that it then becomes more vunarablle to frost damage and that will just accellorate the problem to some extent , remove it and plant another tree to replace it,

[Jwoodgardenmaintenance]

Could you not remove the wall 1m either side and rubuild with expansion joints just to allow movement? 

 

Jack 

 

Edited May 15, 2019 by Jwoodgardenmaintenance

[daltontrees]

It looks like the crack starts below ground i.e. the foundation has failed.

 

Expansion joints will only allow more movement, OK if it's seasonal movement that opens and closes, but no good if it's progressive.

 

A solution in the short term is theoretically possible. However, it would involve cutting the broken section of foundation adrift from the good sections on either side. Remove section of wall racked down on either side,  back a couple of feet on either side, cut down to the underside of the foundation but leave in place. Lay G8 or K9 lintel at just above ground level, but bedded only on section of wall that has remained in place, not on the cut-adrift section. Rebuild wall above it. Reduce to 1/2 brick thick for last couple of courses to buy a few years against contact by the stem. Even better, omit a course.

 

Use a 50:50 portland:lime mortar, well plasticised, and it will give some flexibility.

 

That's if the foundation has failed.   it's basically a bridge across the closest section of tree.

 

K9s are breathtakingly heavy. No tree will lift it purely by growth increments.

[Jwoodgardenmaintenance]

9 minutes ago, daltontrees said:

It looks like the crack starts below ground i.e. the foundation has failed.

 

Expansion joints will only allow more movement, OK if it's seasonal movement that opens and closes, but no good if it's progressive.

 

A solution in the short term is theoretically possible. However, it would involve cutting the broken section of foundation adrift from the good sections on either side. Remove section of wall racked down on either side,  back a couple of feet on either side, cut down to the underside of the foundation but leave in place. Lay G8 or K9 lintel at just above ground level, but bedded only on section of wall that has remained in place, not on the cut-adrift section. Rebuild wall above it. Reduce to 1/2 brick thick for last couple of courses to buy a few years against contact by the stem. Even better, omit a course.

 

Use a 50:50 portland:lime mortar, well plasticised, and it will give some flexibility.

 

That's if the foundation has failed.   it's basically a bridge across the closest section of tree.

 

K9s are breathtakingly heavy. No tree will lift it purely by growth increments.

That's originally what I posted but then realised he said the wall has to stay the same so just put about expansion joints but yeah I'd say that'll be the best course of action 

 

Jack 

[daltontrees]

38 minutes ago, Jwoodgardenmaintenance said:

That's originally what I posted but then realised he said the wall has to stay the same so just put about expansion joints but yeah I'd say that'll be the best course of action 

 

Jack 

I think the key is in detaching the defective foundation from the good foundation so that the former can move below ground and not affect the latter.

 

I wouldn't be surprised to find out that the foundation had failed there partly because it was thinner than normal, and was built like that because of existing roots and buttresses.

Edited May 15, 2019 by daltontrees

[benedmonds]

The Barrell Tree Consultancy Guidance Notes are a great resource.

But this is a big wall and significant movement..

Edited May 15, 2019 by benedmonds

[Justme]

I cant see any options working bar kill the tree or move the wall 2+m.

 

Any less will be short term buck passing.

[Matthew Storrs]

I was going to suggest rebuilding wall on RSJ built in just above the root plate- of course if tree ever went then it’d pull up the wall with it.