The Brew Cabin

I am laying an Indian slate terrace at the moment and I have put down a 100mm scalping base and was going to lay the slate on a full bed of mortar.
However by accident I bought bags of Slab-fix thinking it was premixed mortar. It is actually a lime and sharp sand mix and you don't add water to it. I rang the manufacturers Supamix Ltd who said the mix draws its moisture from the air over time (which could be eternity!) and will never really set hard. The information was annoyingly vague.
I'm worried as I laid part of the terrace a week ago and the slabs still move and the mix is still dry. Because it's been so hot I did spray the slabs to give the mix some moisture, but I am not confident about continuing using it.
Help! Has anyone ever used this mix?! Also what would I point the 20mm joints with, as I think using a mortar would crack if the slabs are so mobile at the moment?

I had a discussion with the folk from Supamix regarding this product and the poor sod they put up to answer my questions (at a Trade Show in Birmingham) had absolutely no conception of how a pavement works or why a lime-based product was preferred to cement-based. He also suggested that the Slab-fix would be ideal for jointing, which is wrong, and that it would set as hard as "normal" concrete, which is total obllocks. I pointed out these errors and his excuse was that he was a salesman, not a paving specialist nor a builder, which left me completely unimpressed and determined not to recommend this particular product.

In theory, the Slab-fix would 'set' (I think 'stiffen' would be a more accurate term) by drawing moisture from the air and the ground, but you've been unfortunate in that we have just been through a very dry and warm spell, and, because you used a sub-base, there is little, if any, moisture in direct contact with the bedding product.

However, as you sprayed the area with water, it really should have 'stiffened' by now, which leads me to wonder whether this is a perished product, ie, one that's been left on a shelf for too long so that the lime content has hydrated before you opened the pack.

I think this stuff is an expensive bedding and a way of extracting yet more money from non-trade folk who don't realise just how simple and cheap it is to knock-up bedding mix for themselves. I would not buy any more Slab-fix, but would switch to a tried and tested bedding material, namely sharp sand and a dash of cement, such as the 10:1 mix I advocate.

As for the pointing, use a Class II mortar, as described on the main site, or take a look at the pages that deal with the art of pointing for a fully detailed guide to what works and what doesn't.

Thanks very much for the reply and so promptly too! I'll feel much happier using the tried and tested method :-)