DPM On Hardcore

[Skavenger]

Hi;

I am laying some hardcore in advance of concreting a garden workshop floor. Do I need to put anything on top of the hardcore before laying a DPM? It looks as though it may get punctured / torn on the hardcore edges?

Thanks

 

[23vc]

Sand blinding, lots of info on this forum or Google

 

[KenGMac]

Skavenger, good evening.

Suggest you consider a layer of sand between DPM and hardcore.

But? the sand can wash out if the edges are not closed of with a brick perimeter wall or similar. mixing cement will reduce leaching of the sand.

The most commonly used material is a so called "Lean mix Concrete" a "Weak Concrete mix" generally 50.mm thick, generally less than 7.5 Kn. Can you adjust the heights to accommodate the Lean mix?

Ken.

 

[Skavenger]

Skavenger, good evening.

Suggest you consider a layer of sand between DPM and hardcore.

But? the sand can wash out if the edges are not closed of with a brick perimeter wall or similar. mixing cement will reduce leaching of the sand.

The most commonly used material is a so called "Lean mix Concrete" a "Weak Concrete mix" generally 50.mm thick, generally less than 7.5 Kn. Can you adjust the heights to accommodate the Lean mix?

Ken.

I could 125mm hardcore, 50mm weak concrete and 75mm concrete?

What would be a weak mix 10:1 (Ballast / Cement)

But sand would be easier, the hardcore comes to the top of my wall footings so the sand would be encased by four walls. So I just even out the hardcore with sand?

Sharp sand or builders sand?

 

[Red_Shift]

Sharp sand or builders sand?

Sharp sand

 

[23vc]

I used building

 

[^woody^]

Soft building sand

 

[Skavenger]

Thanks everyone - looked and sand binding seems the simplest option.