leylandii extension

[Gladys1922]

I want to build a two storey extension over my driveway. The neighbor has a leylandii hedge approx 7 foot tall along the length of the driveway boundry . The hedge is 3m ( the width of the driveway) from my house but only 40cm from their single storey kitchen extension (at the rear of the house) and 90cm from their house . The trees are only about 40cm apart and have been in situ for approx 20yrs ( put in by the previous owner of the house) so it would be a bugger to try to pull it out . Would it be enough to just kill them off and cut them to ground level ? We had double gates put across the driveway and when the guys put the gate posts in, they needed to put a post a foot longer in on the hedge side. So there would appear to have been a degree of damage done to the ground level already with implications for the laying of foundations for an extension. To complicate matters further they have decking at the back right up against the leylandii .

 

[Gladys1922]

I should add that the neighbors are't bothered about the hedge but would want something to replace it eg: a fence.

 

[theprinceofdarkness]

You don't say how close to your boundary (driveway edge?) your foundation trench will be. I would think you have to go at least one metre lower then the roots to get decent footings. also how narrow the gap between your new building and your neighbours?
Frank

 

[Gladys1922]

The extension would take up the whole driveway so would be on the boundary where the hedge is. The distance from the boundary to the neighbors house is only about 1m .

 

[jeds]

Calculation shows a foundation depth of 1.25m as long as the trees are fully removed. Are you certain they are Leylandii though. They should be a lot taller after 20 years.

 

[Gladys1922]

The trees are def conifer but I just assumed that they were leylandii. The current owners don't know either. The trunks differ in size considerably . Some are double or triple trunks from the base up. The largest trunks are approx 20cm, the smallest is about 4cm in diameter. They are only about a foot apart and have been trimmed and the tops taken off ( after a fashion). The owner is very lax and the trees are def bigger than when we moved in 5yrs ago. I've tried to upload pics but not having much success .