Garden drainage

[b21playa]

Hi all

Building a new retaining wall and planning to add a 100mm perforated drain at the back to help with drainage. Would i still need weep holes?

 

[plastic_peanut]

I would just as a precaution

 

[b21playa]

I would just as a precaution

Thanks

I’ve seen 15mm pipe being used, how are these used when joints are 10mm?

 

[plastic_peanut]

It really depends if they are installed when the wall is built or retrospectively.

There are quite a few articles which should assist you with a google search

 

[b21playa]

It really depends if they are installed when the wall is built or retrospectively.

There are quite a few articles which should assist you with a google search

Would be while building. Seen pictures but no articles

 

[Halitosis]

Will your perforated pipe drain to anywhere? If not then it wont serve much purpose and weep holes wound definitely be required. What will you have in front of the wall? If its a patio then you won't want puddles from the weep holes. Larger holes are better to prevent blockages forming. Paving Expert website has a good section on retaining walls which was my guide when I built mine. Best to have drainage gravel above your field drain behind the wall too, and geotextile to keep it all separate from the soil.
Retaining wall blocks are a good solution as they don't require mortar (literally build them up dry like lego) so water can drain through negating the need for weep holes.
Good luck

 

[b21playa]

Perforated pipe will connect to drain where other surface water drains to. The back on wall will be filled with gravel separated as you say

 

[Halitosis]

Then if you lay the field drain well you shouldn't be needing weep holes. Happy days

 

[b21playa]

Then if you lay the field drain well you shouldn't be needing weep holes. Happy days

Thanks for that

Not really looking forward to barrowing 10-tonnes of gravel to the garden

 

[Halitosis]

Blimey - hoping that's not all for behind the wall... dare I ask the size of this wall?

 

[b21playa]

Blimey - hoping that's not all for behind the wall... dare I ask the size of this wall?

The wall will be around 16m across and then the sides around 4m each. About 1m tall

 

[Halitosis]

That's a sizeable wall! What are you constructing it of? Cement blocks?
Mine is closer to 10m long and a similar height but I think I only used 2 tonnes of gravel behind it. We stood plyboards behind it as a divider with geotextile fabric and filled the gravel against the wall behind the geotextile/ply while we back-filled the soil the other side. Once filled to height we used the digger to pull out the ply. The gravel was probably 6-8 inches width behind the wall (with the field drain at the bottom also wrapped in geotextile). Please post photos as your project progresses!

 

[b21playa]

This is it at the moment. Will be built with Co concrete block inner and brick outer. It will all depend on gap between wall and soil for gravel quantity, It should be less than 10t as I forgot walls will be 3/4 bricks thick towards the bottom to strengthen it

 

[Halitosis]

Superb - and looks like a bigger scale though not dissimilar project to mine, which I wrote about on here a few years ago: https://www.diynot.com/diy/threads/garden-levelling-retaining-walls-and-patio.436119/#post-3399790

Cracking looking garden you have there and looking forward to seeing the end result.

BTW judging by your photo it might be time to switch hands with the shovel as the right shoulder is looking bigger than the left

 

[b21playa]

Superb - and looks like a bigger scale though not dissimilar project to mine, which I wrote about on here a few years ago: https://www.diynot.com/diy/threads/garden-levelling-retaining-walls-and-patio.436119/#post-3399790

Cracking looking garden you have there and looking forward to seeing the end result.

BTW judging by your photo it might be time to switch hands with the shovel as the right shoulder is looking bigger than the left

Thanks, just seen yours and it looks very good, you should be proud.

where did you get them blocks from and are they easy to lay?