Where the roots are
Tree roots spread wider than most people expect, often beyond the canopy, and most of the fine feeding roots are in the top 600mm of soil. That is exactly the depth a conventional drive digs out.
Root protection areas
Arborists calculate a root protection area for each tree, based on the trunk diameter. Within it, excavation, compaction and impermeable surfaces should be avoided or carefully designed. For a large tree near your drive, an arboricultural assessment is worth the cost.
Construction options
| Method | When to use it |
|---|---|
| No-dig cellular confinement | Within the root area; builds up rather than digging down |
| Permeable surface on top | Gravel, resin-bound or permeable blocks |
| Reduced dig with hand tools | At the edge of the root area |
| Conventional build | Well outside the root area |
A no-dig build raises the finished level, so it needs planning at the edges and where it meets the footway and the crossing.
Street trees
Trees in the verge or footway belong to the council. A crossing is unlikely to be approved if it would harm a street tree, so the crossing position may have to move. Check before you design the drive around a particular opening. See dropped kerbs.
Protected trees
- Tree Preservation Orders: consent is needed for works, including those that could damage roots.
- Conservation areas: six weeks' notice is required before most tree work. In Thornaby, that includes Thornaby Green.
Common questions
Will roots crack my new drive?
They can lift rigid surfaces. Flexible, permeable builds cope better.
Can I cut roots that are in the way?
Small roots, sometimes; major roots, no. Get advice first, and consent if the tree is protected.
Which surface is best near trees?
Gravel in a no-dig grid, or resin-bound on a porous no-dig base.
Do I need a survey?
For large or protected trees close to the drive, yes.