Trees and Species of The Larger Plants

Landscaped gardens and green spaces are an extremely common features. Existing homes or buildings may have also been built within close proximity to plants. Larger plants can cause huge stress to buildings as their roots will continue to grow throughout the plant's life span. Whilst growing, the roots can disrupt a building's foundation. Precautions and set measurements have been legislated to prevent subsidence.

A root can disturb the building before reaching the foundation. According to the RICS ‘The potential damage is most often not due to direct physical pressure exerted by roots as a tree has to be very close to the structure for such damage to occur. Most damage is secondary in nature particularly with soil types that shrink considerably on drying’. As the plant is a living organism it will require water to survive. Thus, the plant will extract water from the soil in order to live, breath and grow. This may cause the soil to dry out affecting the soils durability.

Clays or other fine particle soils will shrink in an attempt to withhold as most moisture as possible. This can typically happen after a period of draught. The reverse will happen after sustained periods of rainfall. British Standard 8004 (2015) recommends a minimum depth of 1m for foundations. But if there are, or were, trees nearby, depths of up to 3m may be necessary. This is clear evidence from industry experts that precautions must be made when building or excavating around trees or larger plants. Calculating the correct distance is vital for the building's longevity. A good guide to use is from Darlington Borough Council. You’ll note the distance is calculated dependant on the plant or tree’s species.

One species of the plant not mentioned by Darlington Borough Council is Japanese Knot Weed. It originates from volcanic regions in Japan and was a hugely popular plant throughout the 19th century. Although it’s pretty to look at, the weed in the 20th and 21st century is considered to be a nuisance. It grows at rapid speeds and in most terrains. Like most roots it’ll grow around a solid object or building. 

But as the plant grows at such a rapid speed the root needs to be identified at an early stage. Treatments are long and tenuous with the most common being chemical treatment; Chemical treatment can cure the issue but may also contaminant the soil for years to come. To conclude, I believe that a Tree or plant roots can have a disastrous impact on buildings if located within close proximity to the said building. Carefully considered planning needs to be implemented in order to make the build safe and secure for a sustained period of time.