Tree Root Damage To Foundations
Foundations can be damaged by a variety of factors, and tree roots might be one of them. There are several ways that tree roots can have negative effects on foundations. The first one is to touch the foundations physically. Tight contact may result in damages on foundations. The second one is to change the elements of the soil like moisture to cause indirect damages on structures. The third reason is that tree roots may generate gaps in soil which will shift the foundations of buildings etc.
The damages of foundations due to physical contact of tree roots and the buildings may be different based on different factors like tree species and size, type of buildings, soil conditions etc. The size of the tree is one of the important factors. Most gardening trees will establish their root system within a depth of less than 2 meters under the surface of ground. The normal span of the root system can be several times of the tree crown. So, if you have several tall trees nearly your house, their roots may already grow under the foundations. The structure of the foundation is also important and some structures are capable of tolerating more invasive roots than others.
Also, tree roots can affect the moisture of the soil especially the soil under foundations due to tree roots will absorb water and nutrients from the soil. Since the tree root is the only way to pull water for the tree body, they will stretch to any places where there is water including the space under foundations. If a tree near a foundation dies, its roots can be another issue. When their roots have decayed gradually, they will leave empty gaps in the soil which may cause the foundations to move. So, you should think thorough before removing a dead tree beside your house.
Image provided By Hongshanyingyue (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons