Tree Root Damage: When Pines Lift and Crack Your Pavement

How roots damage pavement

Roots grow where there is water, air, and loose material. The gravel base under pavement often has all three, and the pavement itself holds moisture underneath. Roots follow that edge and grow along it. As they thicken over years, they lift whatever is above them.

The damage pattern is distinctive. You get a raised ridge, often curving, running away from the trunk. Cracks open along the crown of the ridge because the asphalt is being bent. Once cracked, water enters, and the usual freeze-thaw sequence takes over.

Roots also do damage you cannot see. A root thickening under the pavement lifts and loosens the base around it, so the area near a visible hump is usually weaker than it appears.

The Tahoe version of the problem

Jeffrey pines, lodgepoles, and firs are all over the properties we maintain, and many driveways and HOA roads were cut through mature stands. Trees that were small when the road went in are now large, and their root systems have had decades to find the pavement edge.

Shallow soil over rock pushes roots sideways rather than down, which makes the problem worse here than in deep-soil areas. Add the shade those same trees cast, which keeps pavement damp and slow to dry, and you get two problems from one tree.

Landscaping decisions made decades ago show up now. Trees planted close to a new driveway are always small at planting and always large later.

What maintenance can address

Cracks caused by root lift can be sealed while they are still tight and the surrounding pavement is sound. Hot rubberized sealant keeps water out of them, which is worth doing because a root crack is usually in a shaded, slow-drying spot that stays wet.

Sealcoating protects the surface as usual. Understand the limit. Neither product stops the root. If the root keeps growing, the crack reopens. Sealing is buying time on a problem that has to be solved at the tree, not at the pavement.

Look at whether the crack curves. Root cracks generally follow the root and bend with it. A straight crack near a tree may be an ordinary thermal crack with nothing to do with the roots.

Solving it for real

Permanent fixes involve the tree. Selective root pruning by an arborist combined with a root barrier installed between the tree and the pavement is the standard approach. Removing the tree is the other option and often the one nobody wants to hear. Cutting large structural roots without an arborist risks the tree and, on a big pine, risks whatever is downhill of it.

Once the root issue is resolved, the lifted pavement usually has to be cut out and replaced. That is paving work and not something we do. Call (530) 587-4161 and we will look at it and tell you whether the cracks are still worth sealing in the meantime.

Do not put off the diagnosis. Root damage that gets sealed and ignored for five years ends with a larger repair area and a larger tree to deal with.

Quick answers

More in the pavement guides and the FAQ, or see every pavement problem we get asked about.