CLPM are home renovation specialists. We don’t design, and we don’t build, but we have a deep understanding of both disciplines. As such we can offer independent, specialist advice and can help organise almost every element of your home renovation building project for you.

CLPM are a construction project consultancy. We work with industry professionals and for residential homeowners and over the years have worked on dozens of home renovations. From historic, listed properties to Victorian and Edwardian homes, and post-war and 1960’s refurbishments.

We offer construction cost services, independent energy efficiency and heating system advice, and bespoke building project management support.

Unlike many of our competition, our staff are all highly experienced and many are extremely well educated, with industry-respected degrees and a variety of other valuable qualifications.

Among our team we’ve got the collective knowledge and expertise of a fully qualified architect, a chartered quantity surveyor, two building surveyors, a mechanical engineer, a civil engineer, a fully qualified plumber, a buildings insurance expert and a property planning and development expert!

We provide support for a number of industry shows and events including Grand Designs Live, Build It Live, The Ideal Home Show and the NSBRC. At last count, we estimated that our team has worked in the building industry for a combined total of 225 years – not bad!

In this blog, Alistair Stewart, one of our building project managers, and a qualified bulding surveyor, talks about his experience of damage to houses from roots and trees. All too often a major problem for many home renovators………..

Trees, roots and crack damage to buildings

That tree roots cause subsidence is an over-simplification. It’s important to understand the pattern of movements to foundations, both vertically and laterally. Seasonal movement is common. If the movement is under 10 mm, it is unlikely to cause damage. Quite often 30 mm is in the normal range. One needs to understand the mechanism of the damage in order to implement appropriate remedial measures.

The dynamic condition of soil depends on water. The amount of water absorbed by a tree and lost through its leaves via transpiration is often greater than that supplied by rainfall – thus leading to soil drying out progressively throughout Summer. During Winter leaves drop, and transpiration drops, allowing the soil to recover the water deficit. In some circumstances this is not achieved. The amount of water taken up by trees depends on the availability of water, the species, size and vigour of trees and rate of evaporation through its leaves.

Soil that is predominantly sand or gravel suffers little from changes in moisture content. Clay however will shrink when dried and expands when re-hydrated. The amount of movement depends on the properties of the clay, and re-hydration depends on permeability aspects of the clay.

Buildings tolerate some movement, but an excessive differential movement leads to cracking. Tree root activity is a common cause but there are other causes. Simply assuming that the adjacent tree is the cause can lead to faulty diagnosis and wrong remedial works. A good methodology needs to be adopted, including:-

  1. Investigation of building history, soil, and the tree. From this can be formed an initial assessment.
  2. Carry out levels monitoring regime.
  3. Carry out a level distortion survey using a simple water level. Do not rely on visual observations as the eye can be deceived.

Monitoring of levels is an essential part of investigations. Level monitoring is the most effective method of investigating movements and damage (This must be carried out prior to any remedial work to the building).

Problems due to landslip, mining subsidence, settlement often require a Structural Engineering input and structural reinforcement of foundations (underpinning). However, when dealing with trees, expensive remedies are not always needed – simple tree management in the form of vegetative control should be preferred. A multi-disciplinary approach should ideally be used involving a Building Surveyor, an Engineer, an Arboriculturalist, and a Soil Scientist.

In most situations moisture deficits and associated soil movements are seasonal with full recovery during winter. Simple tree management in the form of vegetative control should be the preferred remedy where damage has occurred. Only in exceptional, rare, circumstances does persistent deficit develop, requiring underpinning. Felling of any trees should ideally be carried out during winter in its time of least activity. This allows for a full season of further monitoring to be achieved, instead of extending this to a subsequent cycle.

Simply relying on a Structural Engineering report or underpinning contractor’s findings may not be the answer. Wrong remedies can be installed leading to more severe damage. For example, finding roots adjacent to your property and installing a root barrier in between (severing roots in the process), could lead to greater re-hydration of the soil and more damaging heave to the property, as water that the tree was previously taking up is then allowed to re-hydrate the soil at a far greater rate.

Are you looking for a home renovation specialist team to help with your building project?

If so then why not get in touch? Call 01923 896550, email info@cl-pm.com or complete a contact form today.

CLPM Project Managers cover London, Bedfordshire, Berkshire, Buckinghamshire, Gloucestershire, Hampshire, Hertfordshire, Oxfordshire, Surrey, and West Sussex. Energy Consultancy and Cost Advice services available across the UK.