A friend of mine had a house built 15 years ago. In order to build it a large tree had to be removed and I am not sure that it was all removed before construction started.

Looking at the situation I am finding tunnels which I think are the result of tree roots rotting out. They go, at least under the drive and possibly under the house.

Their concern is that the resulting tunnels may compromise the drive and house floor integrity.

Which type of company can they call to seek advice on fixing the problem?

What are the accepted ways to fix this problem?

Thanks for your assistance.

 

"Looking at the situation I am finding tunnels which I think are the result of tree roots rotting out. They go, at least under the drive and possibly under the house." How are you finding tunnels? Are you seeing depressions in the landscape where soil is collapsing?

Should sink holes start appearing from decaying of tree stumps or piles of brush the builder covered over, these can be dug out and filled with gravel and tamped, topped with sand. A water hose is turned on to force water into the hole to force gravel and sand into pockets to force settlement. Top with at least 6" of topsoil taken from nearby landscape so soil conditions will match. Time should pass to allow for any settlement and again topped with topsoil if needed before paving over.

Should driveway begin to sink, then asphalt or concrete can be cut out and affected area dug out and repaired with gravel and sand as described above, allowing time for settlement and then driveway repaired.

Should structure show signs of settlement, a structural engineer can be called to assess the situation. One never knows, but it is hopeful that the builder's excavation of the site for the structure removed any roots beneath the concrete slab or foundation. I would be hesitant to over react about decaying root tunnels beneath the home or the driveway unless I saw indications of movement.

Another thought, is that when making repairs with fill in with gravel and tamping and sand and tamping, you can rent a compression tamper. Many contractors use compression tampers before installing driveways, patios, and foundations. This should take care of any future unforeseen problems. Just don't tamp wet soil.

 

They found them whilst digging the borders over and asked me to look at them.

I didn't notice any signs of depression. Those which I saw had not totally collapsed and were fairly close to the surface.

I didn't find any evidence that they were animal tunnels. No droppings or signs of life.

I did find evidence of composted material which I assumed to be tree roots in the areas I could examine.

I think that I will suggest to them that they follow your advice on filling them in.

Thanks for your valuable assistance.