By Jez743
United Kingdom 
Hi
I have two leylandii trees growing within 2/3 metres of my house. They are about 16 feet in height, The trees were planted by the previous owner. I have had them lopped a few times, but they quickly grow back.
I am worried about the tree roots affecting the house foundations possibly causing subsidence or maybe drain damage by making the soil dry out.
If the trees were reduced in size to 6/7 feet would this alleviate the problem or do the trees need to be completely removed?
Any answers appreciated.
6 Sep, 2010
Answers
They are surface rooting, and will take up a lot of water, especially in spring and early summer. Apart from the water which will not be soaked up when they are removed, there is little problem with their close proximity to the house at the size they are. Lopping them each year will stop them causing a problem. However, if allowed to grow, they can reach 60 - 70ft, and might be a little intrusive! Phil J
6 Sep, 2010
That close to the house they are a threat to any drainpipes, particularly earthenware which can crack and the conifers will feed on the sewage etc. in the pipes. Also the roots will undermine the foundations. The width of the Leylandii must already be touching the wall unless cut back severely, I would recommend that they are completely removed.
6 Sep, 2010
They grow 3-5 feet per year and I would say they need to come out as way to near the house.
6 Sep, 2010