Silver birch roots under my patio

[v11f]

Hi all,

I'm new here, so I don't know if this has already been asked ... we have 3 silver birches approx 20 years old, that are planted around 1 metre away from our patio, roughly 4 metres from the house, to provide shade (we live in France). The shade works very well - in winter there's still plenty of light, so we get sun through the windows, warming the house. The patio, installed 20+ years ago, has subsided approx 10cm as the ground has settled and needs redoing: it's no longer even underfoot. I plan to do it in wood, on plastic supports. There are roots running underneath the current patio. I have some questions :

Can I cut these roots, without killing the trees ?

Can I do this on the external perimeter of the patio, which - at its closest, is 1 metre from the trunks ?

To what depth do I need to go down, to get all the roots ?

What kind of root barrier, to what depth, do I need to put in, to stop roots undermining new new patio ?

Thanks all in advance for your help,
Peter

 

[AGoodSteward]

You want to avoid cutting roots where ever possible. Especially on birches as they can be sensitive.
Consider raising the patio supports on pilings and allowing the roots under it to continue supplying moisture through the gaps between the boards.
Are you concerned about the roots reaching your house foundation?

 

[v11f]

Hello, thanks for replying. My main concern is that the roots will continue to lift up the pilings and supports, causing the patio to be raised at certain points. The benefit of a boarded-patio is that I will be able to unscrew a couple of planks, adjust the supports (screwed) to get things level again. But I was wondering what your experience & recommendations are. I don't want the patio to be all slopey after just a few years ...

 

[AGoodSteward]

Ttee roots do the raising damage close to the trunk. When you get a meter or more away from the base they get finer, they grow around obstacles.
If you shear the feeder roots off a whole side or even 25% of a tree it gets serious. Even a little chopping can open it up for infection.
Think of it like surgery, keep the cuts neat and clean. Don't chop, slice, with a sharp implement.
How deep were you going to bury your plastic anchors. Can you lay them on top without disturbing the roots?

 

[v11f]

Hi, thanks for the advice. I'm now thinking I'll leave everything in place, save digging a trench so close to the trees which would mean cutting some substantial roots - I think I'll take the risk of things moving, and having to lift up some boards and adjust the plastic supports. Shouldn't be a big drama ...

 

[AGoodSteward]

I wish you well with your project. My wife and my favorite spot is on our patio under a box elder tree.