Page 1 of 1

Advice please on the effect of trees and ivy on a dry wall

PostPosted: Sun Jul 06, 2008 6:16 pm
by efr2
On our property in France we have a dry stone wall which is a retainer wall for 2 levels of ground. The property was built about 25 years ago and the wall is probably that age too. The wall retains a garden behind it dropping about 10 feet to road level. Recently we employed a reputable company to landscape the garden behind the wall. They removed a couple of trees, bushes and a lot of ivy that was growing over the garden and, although not profusely, on the top of the wall itself. 6 months later, after heavy rainfall over a period of 2 weeks, the wall collapsed. Could anyone tell me please if the wall could have collapsed because of the removal of the ivy and the vegetation in the garden or would it mainly be due to the heavy rainfall? Any help would be appreciated. Many thanks.

PostPosted: Mon Jul 07, 2008 1:09 pm
by jerryg
In my experience of ivy, it doesn't seem to harm a wall unless the growth is great and it is exposed to high winds. In some cases especially the ancient limestone walls around here the ivy is doing a good job of keeping old and knackered walls from falling down.

In your case if your contractors removed the ivy and the uncovered wall was in a poor state you could blame them for not telling you. The removal of ground vegetation near to the wall will have greatly increased the flow of water towards the wall. Also the removal of trees and shrubs and their root systems will have de-stabilised the ground allowing rainwater into the soil.

The heavy rain you had would then seep into the ground faster and drain downhill toward the wall, having nowhere else to go will have pushed out the wall. Where did the water go when you had heavy rain before your landscaping?

When the walls were originally built the original wall builders may not have put in adequate drainage. It might not have been their fault. They may not have thought of the effect of future activities in the garden. They could not have foreseen the greatly increased amount of heavy prolonged rainfall we seem to get nowadays.

We seem to get a lot more heavy rainfall around here than we did 25 years ago, is it the same in France?