Tree Root Damage to Buildings provides a comprehensive analysis of how the interaction of trees, soils and water can cause foundation movement and damage to properties.
Subsidence of houses is costing the insurance industry in excess of £500 million pounds after each dry year, and is usually the second most expensive insured peril, after fire. In the majority ofcases, particularly on clay soils, trees are the main cause of subsidence. Concern about subsidence is a major worry to house owners, not only when trees cause damage but also because the proximity of trees can jeopardise house purchase and mortgage loans.
The problems are multi-disciplinary, involving structural engineers, surveyors, arboriculturists, soil scientists, insurers and their loss adjusters, architects, builders and planners, as well as giving work to solicitors and barristers. Existing publications are presented from a single viewpoint, or only cover part of the problems. This book addresses all aspects, and so is of value to all these professions.
Causes, Diagnosis and Remedy are covered in Volume 1. It describes the tree and its root system. and soils with special reference to the behaviour of water. It draws on the author's extensive research (which is presented in \blume 2) to consider the patterns of seasonal and persistent soil drying which develop near trees on day soils, and how these interact with the building to cause foundation movement and damage. ln the past the remedy for subsidence has usually been to underpin the foundations, but it is increasingly realised that other solutions, particularly tree removal or in some cases tree pruning, can provide an effective and far cheaper alternative. The author is a keen exponent of this approach, but it requires careful diagnosis, targeted at obtaining the essential information. The techniques which the author has developed for this purpose are described, and at the end of each chapter there is a Case Study illustrating the methods and results.
The author's experience as an Arboricultural Consultant allows a thorough appraisal of the options for felling or pruning trees, and other methods of controlling root activity. Methods for predicting and preventing damage are described, as well as the legal implications of tree root damage, including the practicalities of Tree Preservation Orders. All of this has implications for the management of trees, both for arboriculturists and other professions. Volume 1 also describes how trees can cause damage on any soil by their direct growth, and how this can be prevented. This includes damage to drains and other services.
Patterns of Soil Drying in Proximity to Trees on Clay Soils are described in Volume 2. This provides the only full and comprehensive presentation of the wealth of data derived from the author's research over the past 20 years. It describes projects which were
commissioned by Milton Keynes Development Corporation, National House-Building Council and the Department of Environment. They have involved the detailed monitoring of patterns of soil drying in the proximity of a total of 60 trees growing on a variety of clay soils. This monitoring covers both the seasonal and long-term changes in soil moisture content over the period from 1978 to 1995. The data for each tree is presented in a series of full-colour graphs. These provide a unique record, summarising the results of about 94,800 measurements of soil moisture content.