BRE DG475 PDF

This Digest provides guidance on the assessment of the significance of tilt of low-rise buildings resulting from foundation movement. It should assist building professionals, property valuers and insurance advisors in assessing the significance of tilt and the need for expert advice.

The Digest covers investigation if tilting appears to have taken place, how to monitor ongoing tilt, and remedial action if that should prove necessary. How to design a stiff raft foundation in order to avoid excessive tilt is also briefly examined. Includes a table of limit values of tilt for different types of structure (chimneys, towers, warehouses, radar systems, etc).

The issues of acceptability and tolerability of tilt are particularly acute in low-rise housing. The shortage of good building land and the consequent necessity of siting new housing developments on more marginal sites gives added importance to the subject. This Digest is complementary to Digest 251 which deals with structural distortion and cracking caused by foundation movement.