Weepholes

Hi, hoping you can help again!

What specifically should I use for weep holes in a retaining wall? Someone mentioned copper would degrade, albeit over a long period of time. So shall I use the equivalent plastic pipe used in plumbing, or a type of waste pipe? And should there be some kind of membrane to cover the end so the back fill gravel doesn't fall down it? Or I thought about covering that bit with rubble. As you can see I am not sure.

I don't know what I'd do without you lot - thank you for any help!

There are lots of alternatives that you can use.

A good place to start is www.cavitytrays.co.uk they have a whole range of weep hole utilities. A simple plastic pipe of say a 50mm diameter is ideal, however is the wall in a prominent place? If so something a little more visually acceptable would be better such as a small weep hole. Another point to remember is that staining from a metal pipe is inevitable.

An alternative to the weep holes to remove water is a granular fill (french drain of sorts) on the inside of the retaining wall with a fall leading to a drain point built into the new section of wall. This however will depend on the amount of pressure from the soil/ground that you are retaining.

A layer of geotextile matting as a membrance fixed to the wall on the side to the retained will help to prevent blocking of your weep holes & reduce staining from any material held within the water. This is available from most DIY centres or building merchants.