Slabs over old concrete path

[AlanJohn]

I have a concrete path, that’s old but basically in good condition, apart from a few cracks. To improve the look, and also raise its height, I want to lay slabs on top (mixture of 600x600 and 600x300; cast concrete with nominal 38mm thickness). I’m trying to decide whether I should do this using the standard bedding layer described on this wonderful site (i.e. semi-dry 1:10 sharp sand mix 35-50mm deep) or, because paths are so narrow compared with patios (mine is about 900mm wide, so only 2 slabs wide), to think of it more like bricklaying where you want the slabs to be stuck to the concrete, and so use a wet mortar mix (i.e. about 1:5 soft sand plus plasticiser) with probably a thinner bed. There will be soil or grass on both sides of the path but I'd still like the slabs stuck to stop them moving.

Thanks in advance for any advice

[alan ditchfield]

This is possible but the mix will be weaker than it would be with a grit sand, why dont you haunch the edges of the path or use a wetter grit sand mix.

[84-1093879891]

I'd lay the flags on an 8:1 wet mix of grit sand and cement, with plasticiser.

I've never yet heard a good justification for the use of soft sand when it comes to laying paving. The coarser nature of a grit sand makes for a stronger mortar/concrete and there's no discernible difference in the adhesion of mortars of the same strength, regardless of what may have been stated on a certain TV programme.

Soft sand, aka building sand, is great for making bricklaying and pointing mortars. It's wasted on bedding mortars and concretes, so save it for the pointing and lay the flags using a grit sand. :)

[AlanJohn]

Many thanks for the advice - I'll use a wet mix with sharp sand, when I finally get round to it (I started thinking about this project about three years ago!).

Also enormous thanks to Tony for setting up and maintaining this site - besides the mounds of useful information and advice, it's attractive without being bogged down with ridiculously fancy whistles and bells, is laid out in a beautifully simple way (possibly like a good set of paving?), technically works quickly and efficiently and overall has a very supportive community spirit.

Thanks again.