What mix to use to fill external ground voids

[Bazdaa1]

Was going to lay membrane on a small external storage cupboard and gravel over with 20mm shingle/gravel.

Then I started cleaning it up, removing the loose from the ground and it turned out to be more than expected and so am looking for ideas.

Need to fill the voids with cement/ballast mix to bring it level within reason. I was then going to add the membrane/gravel on top, but now thinking could just smooth render over the top (after the ballast).

Do I need to add some water proofer to the mix, especially where it meets a wall, if so which product? Should I drop a few bricks in the void to reduce the amount of concrete needed? I’m assuming it can be poured straight on top of earth/soil/remnants of previous filling that previous person poured, although have removed as much as I can.

Can I fill the deep voids in one go?

Thanks

 

[Deleted member 323070]

I am sorry to say that it sounds like you don't have scooby.

You can't lay a membrane on gravel.
You can't cover gravel with a membrane and expect it to perform as a membrane.
A smooth render over a membrane won't last a week before it breaks up into pieces.

As it's an outdoor cupboard, you can do what the heck you like, it ain't gonna matter.

 

[Bazdaa1]

No need to apologise, unless it’s to yourself regarding your response.