Sub base for slabs - Is an extra layer of sand required

[Grahamh8]

This question has probably been asked many times, but I'm unable to find it!
I have laid a mot 1 sub base for my patio to a depth of 100mm.This layer is fairly well compacted and has sufficient fines to fill the gaps between the crushed stone. Its for light use only and has been leveled.

Do I now require another screed layer of sand before the bedding mortar layer of 10:1 sharp sand to cement, or can I go straight to the bedding mortar layer

[lemoncurd1702]

Straight to the bedding mortar. I've seen this layer of sand business in so many books over the years and never quite understood the point in it.
They were the same books that recommended laying on spots :p

Maybe go a bit stronger on you mix 8:1 at least.

[Grahamh8]

Thanks for the advice.

[Tony McC]

Yes, I too have seen the mystery 'intermediate sand layer' in some books about paving, and it is immediately apparent that such books were written by fools with no real experience and buggerall in the way of skills or understanding of pavement structure.

I suspect such a ludicrous construction was shown in an amateur guide many years ago and then a succession of copycat authors took it as gospel because they knew no better.

The *correct* methodology is shown on the main website.....