I have a columnar Yew which currently is about 18 - 20 feet tall with a spread of about 6 feet. What is the root system like for these trees and what effect will/can it have on the foundations of the house?
The centre of the trunk is only 3 feet from the building. I am concerned for two reasons:
The impact of roots on the footings
The extra moisture content of the soil if it is felled
It is a beautiful tree which at present causes no problem. There are no cracks appearing!
In most cases, a yew such as you have described will not harm footers/foundations. There is one case where they can be an issue. That is if your foundation is an old stone foundation. My house has a 100 year old stone/mortar foundation, in direct contact with the soil. The outside has some areas underground where the mortar has broken down enough that roots could get in. Technically, they could grow into the cracks, increase in diameter, and cause foundation failure. But even though I have aggressive rooting norway spruces right up to the house, I have no issues.
If your foundation is a block or poured foundation, I wouldn't worry about it at all, so long as the tree isn't right up against it. The main roots taper quickly.
If you do get it cut, remember that most of the moisture it picks up is from the top 2 feet or so, and if it's removed, a tree that size won't really affect the foundation moisture wise.
