Magnolia Tree too close to house? Protecting foundations

[MikeEdStan]

Hi All,

 

This might be a very straight forward one... We have a magnolia tree at the front of our recently purchased house. A structural engineer has suggested it should be removed in case of damage to the house. Most advice online would suggest the same, however it would be a shame. I'm wondering if there is anything that can be done to protect our foundations and save the tree?

 

The tree is just 5 foot from the house. It must have grown quickly, and is near 20 foot high, has a 10 foot crown and a 6 inch trunk. The front garden is raised, but slopes towards the front wall and pavement. You can see on the photo that there is a lower path about a 2 foot drop on the far side of the tree, so most/all routes will be across the lawn. The tree slopes towards path, which is also likely because the front is north facing.

 

There is also a smaller cherry about 8-9 feet away that we'll prune to keep it from growing any larger.

 

Hoping for advise on what we should do? Are there any options to save the tree? or should we remove?

 

Thanks in advance for viewing this and any responses.

[daltontrees]

And where is this? When was the house built?

[MikeEdStan]

Hi, thanks for your interest. This is in the Bristol area. The house is 1903, and so we've been advised that the foundations will be limited (not sure what this means exactly). There is no basement, but a deep void (about 3-4 feet) under the front room, so likely 2-3 feet down from the lawn. The house has had slight historic movement, which has settled, but this was the reason the engineer surveyed it.

 

I'm interested to understand what I can do to learn how the roots might be getting close to the house (digging/scanning etc), and whether there is some sort of cost efficient (and longterm) barrier I could put in myself. and whether we can get away with pruning/managing it. I had a tree surgeon over, and he felt both trees are a risk, but was also clear that this was not his expertise. He advised removing it and planting something smaller that we keep on top of. Most of the houses along the street have a small tree or two in the front. I recently heard one house had to have underpinning done, but this was (apparently) down to a lack of pollarding of the trees on the street.

[GarethM]

Most houses prewar didn't use any concrete foundations, generally it's a stepped footing arrangement.

 

Kinda like a tapered foot 3-4 bricks wider than the walls. Which understandably is liable to move if disturbed though digging too close, root damage etc 

 

Best to remove the tree and keep any trees away from the walls, unless you want to spend lots of money underpinning.

[Dan Maynard]

I've recently been asked to fell a tree because the insurance company stipulated no trees within 10m of the property. Seems bonkers to me but it's only a misshapen young willow so I guess least risk is to remove.

[Mark J]

You need to find out whether you're on clay soil or not; trees can be troublesome in clay soils when in close proximity to structures. 

[daltontrees]

On 28/02/2023 at 10:46, MikeEdStan said:

Hi, thanks for your interest. This is in the Bristol area. The house is 1903, and so we've been advised that the foundations will be limited (not sure what this means exactly). There is no basement, but a deep void (about 3-4 feet) under the front room, so likely 2-3 feet down from the lawn. The house has had slight historic movement, which has settled, but this was the reason the engineer surveyed it.

 

I'm interested to understand what I can do to learn how the roots might be getting close to the house (digging/scanning etc), and whether there is some sort of cost efficient (and longterm) barrier I could put in myself. and whether we can get away with pruning/managing it. I had a tree surgeon over, and he felt both trees are a risk, but was also clear that this was not his expertise. He advised removing it and planting something smaller that we keep on top of. Most of the houses along the street have a small tree or two in the front. I recently heard one house had to have underpinning done, but this was (apparently) down to a lack of pollarding of the trees on the street.

Parts of Bristol are on shrinkable clays. Susceptibility to subsidence is based on your locatwion being on such clays and the foundations being not deep enough to avoid influence of shrinkage and thirsty trees being present. Shrinkage is becuase trees are taking up water from around them, I don't thnk it's practical to put in what would have to be a waterproof barrier to a depth of as much as a couple of metres.  If clays are present, not only do you want to avoid subsidence but you want to be able to recover repair costs from an insurer if it does happen. Key point A, get insurance, key point B follow the engineer's advice or you might be in bother later. Or be really brave and check for the existence of shrinkable clays at your exact location. Personally I can't see a magnolia that size being an issue but in the future possibly. Who knows what the foundations are like, it is more likely that the outside levels have been raised than the inside being lowered.

 

Plan C. manage the Magnoia by frequent pruning. I've always found them really difficult to get to heal pruning wounds, there's a gap of about 2 weeks to prune in. Plan D, try pruning and if it destroys the tree then start again by planting in a buried container.

[MikeEdStan]

Thanks All.

 

I should have a good idea of what the soil is like next week - we have someone using a mole machine to replace the lead pipework. It's very likely to be clay low down, but as daltontrees suggests, I'm sure the lawn is raised (I'll check the soil). Unless the molar surprises me, I'm 95% I want it out and replaced.

 

So, here's for the novice question...if I aim to move it (to the back), do I have any chance of survival? I know this depends on approach, positioning, but mostly on the size of the tree. If I do this, I'd probably try for next weekend, and I'd need to prune it quite heavily to get it through the back gate, to keep the wait/size down and to keep no more than 3 feet diameter of roots. I wouldn't be too sad if it didn't work out (considering it'll be a last attempt to keep it), but I'd be very happy if it did! 

 

Thanks

[Dan Maynard]

20 hours ago, MikeEdStan said:

do I have any chance of survival?

You'll probably put your back out, but survive that.

 

The tree is unlikely to survive the trauma though.

[daltontrees]

Verlry low chance of survival. You or the tree.

 

BTW in teh shrinkable clay sense, soil does not mean topsoil. Where there are no superficial deposits (natural ones) then the subsoil is the bedrock. I use the word 'rock in its (literally) loosest sense, since most shrinkable clay rocks would lose out to a pair of scissors in the traditional game.