building next to a lilac tree

Question

I am involved in the design of a house extension, which has planning approval, one wall of which is on the boundary with the neighbour’s garden. About 2 metres away from the new wall in the neighbour’s garden is a lilac tree, about 3 metres high. Will the new building, with foundations about a metre below ground level, affect the roots of the lilac? If so, what precautions can be taken to protect the tree?

Answer 1

Depending on the type of lilac variety, most structures (and sewer lines) should be kept at least 8 to 10 feet away. As a general rule, tree roots will extend up to 2.5 times the height of the tree, and some species of trees may have roots extending five to seven times the height of the tree.