Fir close to retaining wall

[globetrotter77]

Hi
I have a Douglas fir growing at the back of my garden about 30cm away from a retaining wall. The wall has developed a slight lean and is in need of repointing. It’s not 100% clear but the tree is probably to some extent to blame although I’m afraid I have let the brickwork get into bad condition. The other side of the wall drops about 6ft to an alleyway (about 4 foot of wall is retaining). The fir is approx. 35ft high (having been reduced by ten foot or so earlier this year after neighbours worried that it was swaying too wildly in their direction in storms). The brickie says he can repoint the wall with the tree in situ, and as I am rather attached to the tree and generally don’t like cutting things down, I am inclined to let him go ahead with this.

 

My question is this: with the tree reduced in height, is the root system still expanding? If so, then I guess that in repointing the wall with the tree still standing I am just delaying the inevitable and should go the whole hog and have the tree cut down.

 

But if the root system is likely to be as big as it will ever be, then I’ll keep the tree and strengthen the wall.

 

Many thanks for any suggestions, advice or stories of similar problems!

[Treeation]

Looks like a spruce to me and will grow a lot bigger than that in height and girth and root system will keep growing. Probably best take it out.

[globetrotter77]

1 minute ago, Treeation said:

Looks like a spruce to me and will grow a lot bigger than that in height and girth and root system will keep growing. Probably best take it out.

Thanks for that, I don't know where I got the idea it was a Douglas from. It's not what I wanted to hear, but sounds like good advice nonetheless!

[Treeation]

Just now, globetrotter77 said:

Thanks for that, I don't know where I got the idea it was a Douglas from. It's not what I wanted to hear, but sounds like good advice nonetheless!

Spruce are forestry trees and grow absolutely huge...annaul expansion of the base of the trunk will be pushing the wall in 10years or so....wrong tree in the wrong place

[globetrotter77]

7 minutes ago, Treeation said:

Spruce are forestry trees and grow absolutely huge...annaul expansion of the base of the trunk will be pushing the wall in 10years or so....wrong tree in the wrong place

Ok, good to know. And is that true even if I have the height reduced? The base of the trunk and roots will keep expanding?

Thanks

G

[Treeation]

There seems to be limited eveidence that anything other than a huge crown reduction would have an impact of decreasing root growth...this would kill the spruce anyway and look horrendous

[globetrotter77]

19 minutes ago, Treeation said:

There seems to be limited eveidence that anything other than a huge crown reduction would have an impact of decreasing root growth...this would kill the spruce anyway and look horrendous

Thanks very much for your knowledge and help!

[Guest Gimlet]

Waste of money repointing that wall. It won't have a proper foundation at that vintage and  the tree is far too close. There's bound to have been root heave which is why it's leaning, and if it's removed the decaying root will lead to subsidence. Either way the tree needs to go, the stump removed or allowed to decay and then the condemned section of the wall rebuilt. 

[globetrotter77]

24 minutes ago, Gimlet said:

Waste of money repointing that wall. It won't have a proper foundation at that vintage and  the tree is far too close. There's bound to have been root heave which is why it's leaning, and if it's removed the decaying root will lead to subsidence. Either way the tree needs to go, the stump removed or allowed to decay and then the condemned section of the wall rebuilt. 

Ok, that's interesting. The brickie who suggested repointing is experienced and comes well reviewed. We will get other quotes/inspections before proceeding anyway. Thanks for your input!

[Guest Gimlet]

I've been a bricklayer by trade for the best part of 30 years and I would never recommend remedial work to brickwork with a tree that close unless it was clearly understood that it was for cosmetic purposes only.

It looks like its a 4" wall too apart from the piers, in which case it's too high. The height of freestanding brickwork shouldn't exceed 7.5 times the width, maximum. So a 100 mm unsupported wall shouldn't be more than 750 mm high or it becomes inherently unstable. And usually it's a lot less than that (see table below).

As a rule of thumb, if a freestanding garden wall is leaning by half its width or more over its height, it is condemned. So if you put a level on that wall and it's more than 50 mm out of plumb, it's knackered. 

I'll lay odds that that one's closer to 100 mm out than 50..

 

Edited February 17, 2020 by Gimlet

[globetrotter77]

44 minutes ago, Gimlet said:

I've been a bricklayer by trade for the best part of 30 years and I would never recommend remedial work to brickwork with a tree that close unless it was clearly understood that it was for cosmetic purposes only.

It looks like its a 4" wall too apart from the piers, in which case it's too high. The height of freestanding brickwork shouldn't exceed 7.5 times the width, maximum. So a 100 mm unsupported wall shouldn't be more than 750 mm high or it becomes inherently unstable. And usually it's a lot less than that (see table below).

As a rule of thumb, if a freestanding garden wall is leaning by half its width or more over its height, it is condemned. So if you put a level on that wall and it's more than 50 mm out of plumb, it's knackered. 

I'll lay odds that that one's closer to 100 mm out than 50..

 

I've seen that table before and never understood why it's different in different places!! Anyway, I'm zone 2. The brickie suggested reducing the height and then repointing and replacing the existing coping on top. The wall is actually higher than the adjacent walls so the height not needed. You think it would be better to replace with new bricks or rebuild with existing and new as needed?

many thanks for your help with this!