Flag retainer questions

[Damian_30]

Hi,

I am planning on using some concrete paving flags (750mm height) from our existing patio which I will be replacing to form a small retaining wall. Its maximum height above existing ground level will be max 300mm, although it will quickly reduce over its 4 meter total length.

I was going to build it exactly as on the 'how to' section of the site but when it is up, do I need to put any DPM and filter materials next to it before I backfill? There is a land drain not too far away from the location of the wall so any water pressure should be reduced.

Also, when I've been excavating for the flags, I've noticed that there has been minimal postcrete used around the wooden fence posts. So while I've got access to the base of the posts I was thinking about throwing some extra C20 into give a bit more stability to the posts. Will any new concrete bond to the existing postcrete or do I PVA the existing to help bond the new concrete to the existing postcrete?

Any advice would be very much appreciated.

Many thanks in advance for any information that can be provided.

Damian

[lutonlagerlout]

part 1 follow the site
part 2 are the posts loose damian?
if not leave well alone,all the strength of a fence post is in its depth in the ground,not a great deal to do with crete really,2 foot in is the minimun depth recommended
cheers LLL

[Tony McC]

Flag-on-edge: no DPM required

Fence posts: adding extra concrete can't hurt, and fresh concrete will bond to the old adequately well for this type of project.