As our buildings are almost always built next to existing trees, the design has to consider the impact of trees on foundations. Although this impact is understood and clear guidance on it is set out in NHBC Guidance, we are finding that this issue is occasionally ignored by builders and overlooked by clients. Building Inspectors are rightly concerned about this issue. Unfortunately, dealing with a foundations that was designed and built without taking notice of the adjacent trees could be costly and very disruptive.
Beta Design Consultants have hands-on experience in the design of foundations to allow for the presence of trees, the heave and shrinkage of clay soils, the design of special foundations (raft slabs, beam and pile, mini augured piles, screw piles (also called helical piles) and rafts foundations on piles.
We have also assisted clients in the underpinning design of foundations that were not deep enough to avoid tree damage. Due to our involvement in the assessment of existing and historic buildings, we have seen a large number of damage cases related to trees. In some cases, the problem can be managed without foundation repair. We advise clients if this is the case or if underpinning is required.