Paving lifted by tree roots: repairing the surface and planning around the tree

How do tree roots damage block paving?

Tree roots damage block paving by growing in thickness just beneath the surface. Roots near the top of the ground expand year after year, and because block paving sits on a thin bed, the blocks above are pushed up into a hump, tilted at the edges or forced apart so the joints open.

• Raised humps or ridges running outwards from the trunk.
• Blocks tilted along one edge, creating trip edges on paths and driveways.
• Joints opening and sand disappearing where roots push the bond apart.
• Kerbs and edgings pushed out of line near the tree.
• Dips that appear later, where a root has died back and left a void.

Roots go where they find water and air. The bedding and sub-base under paving can be attractive to them, particularly where joints let rainwater through or where irrigation runs nearby. The general causes of paving movement, including roots, are covered in why paving sinks.

Can the paving be repaired without removing the tree?

In many cases it can. The paving around the root zone is lifted, the roots are exposed and assessed, and the base is rebuilt so the blocks can be relaid flat. What happens to the roots themselves depends on the tree, the size of the roots and how close they are to the trunk.

We are paving contractors, not tree specialists. Cutting a large structural root can destabilise a tree or harm its health, so for any significant tree we recommend advice from a qualified arborist before roots are cut. In a community of owners, trees in common areas are also a matter for the community, and decisions should go through the administrator.

Where roots are small or belong to shrubs and hedges that are due to be removed anyway, the solution is simpler: the roots are taken out, the ground is backfilled and compacted, and the paving goes back down like any other lift and relay.

If you are away for much of the year, it helps to tell us who looks after the garden and whether the tree has been pruned or treated recently. That background, and photos of the trunk and canopy as well as the paving, lets us judge in advance whether tree advice will be needed before any lifting is scheduled.

How do we repair paving lifted by roots?

The repair follows the same order as any lift and relay, with an extra step to deal with the roots and to plan for the tree's future growth. The aim is a level surface now and a layout that can be adjusted again later without starting from scratch.

1. Photograph the raised area and mark the extent of lifting, including a margin of flat paving.
2. Lift the blocks and edgings in the affected zone and store them in order.
3. Remove bedding carefully by hand around the roots to see their size and direction.
4. Agree the root treatment with you, taking arborist advice where the tree is significant.
5. Rebuild the sub-base and bedding where roots were removed or voids found.
6. Where roots stay, set the levels so the paving clears them, with a gentle transition to the surrounding surface.
7. Relay, joint and compact, leaving the area around the trunk free of paving where possible.

A geotextile layer between the ground and the sub-base helps keep layers separate and is often used in repairs. It does not stop roots by itself. Purpose-made root barriers exist, but whether one is appropriate for your tree and site is a question for an arborist to answer.

How can roots be prevented from lifting paving again?

Roots cannot be stopped from growing, but their effect on paving can be reduced. The main measures are leaving space around the trunk, keeping the paving flexible so it can be adjusted, and not encouraging roots towards the bed with water.

• Leave an unpaved area around the trunk, planted or gravelled, rather than paving right up to the bark.
• Keep irrigation lines and drip emitters away from the paved bed.
• Avoid rigid concrete bases close to trees, which crack rather than flex when roots grow.
• Check the paved area near trees periodically and relay small zones before humps become hazards.
• When planting new trees, choose positions away from driveways and paths.

Choosing a tree species or position is beyond our work, but we are happy to discuss how the paving layout can leave room. For a new garden path or terrace near trees, our sister site covers design in garden paths.

Is a dip near a tree always caused by roots?

No. A dip near a tree can come from a root that has died and decayed, leaving a void, but it can also come from a drain, a trench or simply a soft patch of base. A raised hump is much more clearly linked to live roots than a hollow.

Because the remedy differs, it is worth confirming the cause before work is priced. Our subsidence diagnosis service looks at the evidence, and the article tree roots under paving: realistic options goes through the choices owners usually face. Send us a photo and the approximate m² – free, no-obligation quote.

What should be included in a quote for root damage?

A quote for root damage should state the area to be lifted, whether root removal is included and by whom, what happens if larger roots are found than expected, and whether new edging or replacement blocks are allowed for. It should also say whether removal of roots and excavated soil is part of the price.

Excavated soil and old bedding count as construction waste, while removal of green waste from larger roots may need to be arranged separately. Indicative repair rates are on the price site under paving repair costs. The extent of root work is the main uncertainty, so we describe in advance how any larger roots found during lifting will be handled.

Frequently asked questions