By Jojokae
United Kingdom 
Hi, I have a large square that my partner and I dug 35cmmdeep into our garden. We have used weed killer and a membrane on top and initially was going to concrete it but for a more budget friendly plan and aesthetics we want to use stone/pebbles instead. However we have an incredible amount of sand (the type you mix with concrete) I wanted to know if we could use that sand in the hole and tightly pack it leaving 10cm from the top in which we would then pack the rest with pebbles ? Would this work well? Will the drainage be ok? I just want as much info as possible. Also, the hole has a border.
I’m hoping that we can use the sand and that it would provide a good drainage system.
14 Jun, 2022
Answers
Thank you for your response it was really helpful. To answer your questions. The area is level, it is also towards the back of the garden which is around 6-8 metres from the house. Also, the membrane is the thick mesh kind. I can like more holes if necessary. The size is around 2.5 metres by 5 metres.
I already have so much sand (the kind you mix to make a cement mixture) and it will be too much sand to rinse through.
15 Jun, 2022
Also the next building would be school that is around 5 metres away from the edge of the area I want to do. Other than that I have two neighbours either side of me . The gardens are separated by a fence.
15 Jun, 2022
it sounds as if it will all be fine. I was just worried that it might drain back into your own property. Badly laid decking has caused our neighbours problems as it drained back into their house.
15 Jun, 2022
Ok thank you sooo much ! You have been wonderful. I have one last question. Which is better to do?
A) cover soil with weed killer then fill hole with sand and then use the mesh membrane and then proceed with 10cm of pebbles OR
B) use weed killer, then lay a membrane then use the sand and then 10cm of pebbles OR
C) weed killer, lay the mesh membrane then use the sand then lay another mesh membrane then use 10cm of pebbles?
15 Jun, 2022
personally I wouldn't use weed killer as you need to have leaves etc visible to spray and as you have already dug the hole there aren't any plants to spray.
I'd put the sand down then the membrane then the pebbles.
16 Jun, 2022
Weeds don't normally grow through membrane (though I have seen horsetail do it) so you are unlikely to get any growing from underneath it. The more poisons you can manage without the better, but that's just me.
17 Jun, 2022
welcome to GoY.
as long as the membrane lets water through the sand will give good drainage and the layer of pebbles will sit well on the top of it. How big an area are you talking and is it level or does the garden slope? If there is a slope then water will drain down quicker than through soil. Make sure it does not run back towards any buildings causing problems with damp courses or air bricks.
Personally I'd rinse the sand to remove any salt that may be in it before adding it to your garden.
14 Jun, 2022