Hardcore onto soil

[Jack1991]

I’ve recently dug out quite a bit of soil in my garden, the stuff remaining down is quite solid.

I have had 2 tonne of hardcore delivered but wondering what to do, i bought some damp proof membrane to put down below the hardcore but i’ve been told these are completely waterproof and will hold water?

Should i just place the hardcore on top of the soil and whacker plate it, will this be sufficient to stop weeds coming through overtime?

I’m going to lay some concrete flags on top of the hardcore to place a shed on for storage.

 

[Scarlet Pimpernel]

You need a landscape fabric not DPM. Landscape fabric is black, permeable and doesn't stop the weeds growing.

https://www.wickes.co.uk/Products/Gardens/Garden-Maintenance/Landscape-Fabric/c/1016000

This is an excellent guide
https://www.pavingexpert.com/faqmembr
It does argue that landscape fabric is not the correct material, and you really need a geotextile fabric.

 

[sodthisforfun]

I’m going to lay some concrete flags on top of the hardcore to place a shed on for storage.

If you're laying the flags on top of all that and a shed on top, I personally wouldn't bother with any membrane. You will not get weeds growing from underneath. You'll still get weeds growing in any joins of paving slabs still exposed (not under the shed) but those come from weed seeds on top, carried in the wind. Nothing much stops that.

 

[daviesm1976]

The purpose of the landscape fabric / geotextile is not to stop weeds. It is to stop your subgrade/ soil and sub base / mot1 mixing together.

You might use proper geotextile for a driveway but if it is just a patio. You could use the heavy duty landscape material instead of that thin fabric that rips too easily.