The Brew Cabin

Posted: **Thu May 26, 2011 9:57 am**

Hi,
I am about to lay some paving on a 6mx4m area in my garden at the weekend. I am laying the Red/Brown 'Autumn' Stonemarket Marketstone (imaginitive name

) slabs. Since I have realized that they are sandstone I think. In thier planning and laying guide it states the following:

http://www.stonemarket.co.uk/pdf/planning-and-laying-guide.pdf

(ii) TRUSTONE, VINTAGE STONE, MARKETSTONE
Always lay larger face upwards. Coating the back of
each Flag with neat wet cement and PVA additive just
before laying, will assist bonding.

I'm no builder and so I'm not sure how to go about this now. My original plan was to lay the slabs on a 1:6 cement:sand mix dry. But treat each slab individually as they are not calibrated slabs. However thier laying guide, and other references I've found on the net have mentioned that to get a better bond with natrual stone I should use neat cement with PVA.
I'm using Rompox easy for jointing btw.

Now I'm confused.
-Should I use neat cement+pva mix to coat the back of each slab with a thin layer before laying on a dry bed?
-If so, what mix ratio of pva:cement should I use...really no sand in there?
-Will this neat cement make efflorescence more likely?

Any help much appreciated as I'm supposed to be laying this weekend

Posted: **Thu May 26, 2011 10:53 am**

hi, for starters we dont use pva outside as its not frost proof. you need to use sbr. (annoyingly more expensive) i would lay a 4:1 sharp/cement mix, dry enough that it holds together in a ball if you made it like a snowball. throw in the air and if it stays a clump its wet enough. lay the bed (i like about 60mm min) get the height right according to each individual stone, at this point you can put the stone on the mix and remove until you get it right. in a seperate bucket fill 1/4 full of water, add a 4-5 capfulls of sbr, then add cement dust until it thickens to a little thinner than tomato soup. now you can use an old mug to put the slurry you just made on to the semi dry mix. hey presto, the slurry capilarates in to the mix and up in to the stone, instnt bond. no rocking stones the next day and no mess.

dont make the mistake of laying them upside down, as said, the larger surfce area of the stone is always upwards facing this holds the pointing in place.

Posted: **Thu May 26, 2011 2:19 pm**

Thanks for the info

Should I use an SBR in the bedding mix also?

Posted: **Thu May 26, 2011 6:26 pm**

60mm? in a seperate bucket fill 1/4 full of water, add a 4-5 capfulls of sbr, then add cement dust until it thickens to a little thinner than tomato soup. now you can use an old mug to put the slurry you just made on to the semi dry mix. hey presto, the slurry ?capilarates?

Posted: **Fri May 27, 2011 10:37 am**

Why such a strong mix lpad?

The Brew Cabin

Sandstone laying - mortar and pva