Bedding mixture

[bankrupted]

Don't have time to finish my landscaping so I am using a contractor to lay smooth granite flags, 22mm thick.

My contractor wants to use a bed mixture of building sand, grit sand and cement. I think he said 4:2:1

No problem but since I already bought 3 tonnes of sharp sand for 6:1 mixture I don't want 2 tonnes left on my drive which won't be used and of course paying out for the extra 2 tonnes of building sand.

The reason given for using a mainly building sand mix is, he said, he finds there isn't enough suction for the type of flags I am using when using sharp sand only.

Having read all the mix types on this site I can't see any mention of this and all the mixes use sharp sand only.

I would appreciate others opinions. Thanks

[r896neo]

Adding sbr to the mix will deal with the suction issue. Granite, escpeially the light grey can be prone to picture framing so building sand is a bad idea.

Consider using a bond bridge too.

[Tony McC]

Building sand is just wrong for a paving bed. Too soft; too much clay; too fine; too keen to hold on to moisture.

I'd be worried by any contractor who claims it makes for a better bed.