The Brew Cabin

Hello again Tony, thanks for the help with my cleaning of block paving question last week I took your advice on the high pressure water and it worked a treat so cheers for that one!. Anyway I now have a new problem, I have a large patio area made up of riven style slabs and I need to re-point the whole area, usually I would sweep in silversand however the gaps are really wide due to the nature of the slabs profile and i feel the need for something more substantial maybe a cement based grout??,is there a certain way of achieving a solid finish by sweeping in sand and cement or will I have to point up with a wet mix ? god I hope I can use the sweeping method as I know how long it takes to point up with wet mortar I could be there for ever!!!.....thanks once again Tony for your invaluable advice mate......

Matt.

Riven paving usally has what are known as 'quarry fettled edges'. These give a variable joint width, and as such are not really suitable for dry sand jointing; you need to use a mortar.

Now, you could use the traditional method of pointing, as described on the Pointing page, or you could use a Wet Grout, which is also described therein, but this isn't really the best time of year for a wet grout job. If we get a dry spell, and the surface of the paving is dry, you could even try a dry grout, and then water it in, but this method doesn't normally give a firm joint, unless it is properly tooled after wetting.

Of the three, I'd go for the Pointing - if it was late spring or summer, I'd use the Wet grout, but February isn't really a 'drying' month, so you copuld ennd up spending more time cleaning the wet grout off the paving than it would take to point each joint individually.
Besides, pointing isn't too much slower than wet grouting, once you get the knack of it. From my estimating rates, I have figures for pointing 600x600x65mm buttered flags at 42m2 per hour and wet-grouting the same at 55m2 per hour *in summer* or 45m2 per hr in winter. Dry grouting is 86m2 per hr regardless of season, but that doesn't include tooling time.

Cheers Tony, looks like its a spell on the trowel for me!...will a squirt of fairy liquid be adequate as a plasticiser for my mortar??..and would the mixing of builders sand and sharp sand be a good idea for the mix?.....thanks once again...

matt

The owld Fairy liquid will be fine, Matt, but don't overdo it. Adding extra just buggers up the mix. Reckon on around a thimbleful to a bucket of water. Of course, if you buy that crappy cheap Wash-up liquid, you might need twi thimblefuls, but genuine Fairy Liquid is bloody powerful stuff!

I wouldn't mix the building sand with the grit sand unless you have exceptionally wide joints, say 20mm or more. Adding grit sand can make tooling more difficult, especially with tight joints (6mm or less).

If you're using a coloured mortar, silver sand is better, as you're not fighting against the natural sand colour with the dye.