Pointing advice! - Class ii mortar - sbr or not?

[Adrwilliams]

Good afternoon,

I'm looking for some advice from the experts yet again.

Your previous advice has had a big influence on the way that the project has progressed and I'm very grateful for this.

Raj Green Indian sandstone paving just about ready for pointing.

Its been a slow job, but didnt want to point it until the entire area was finished.

Ive taken previous advice and opted for mortar pointing.

I'm going to use a class II mortar at 4:1.

Ive laid the stone on a maximum 50mm bed of 6:1 (grit sand + OPC) and theyre good and solid.

My question is this:

I'm advised to use a plasticiser in the pointing mix.

However, I've used SBR every step of the way (in bedding mix and as a bond bridge) - should I use SBR in the mortar mix also?

And should I use it WITH a plasticiser also?

What are your preferred 'recipes' for mortar pointing on your I S jobs and what additives do you use?

Thanks in anticipation.

Adrian

[lutonlagerlout]

i did some mortar pointing on wednesday Circa 18m2 and our mix was as follows

minimal water maybe 1/3 bucket in the mixer
3 shovels of sharp (plastering sand)
3 shovels of soft sand
12.5kg of cem2
glug glug of SBR approx 100ml
you need it to be dry enough so it doesnt stain but wet enough so that it bonds
hard to explain in writing but like the base of a cheesecake

if its a hot day you may need to mist completed sections every hour or so

pretty much a deluge of rain forecast so keep an eye on the weather

heavy rain will noise it up

the mix above dries out pretty fast

i worked from midday to 4.30 and it lashed down at 8.30 with no ill effects

any snots leave on the paving till they are crumbly and brush off after about an hour

hope this helps

might remember to get a picture tomorrow

cheers
LLL

[Noony]

christ tony,

i read that as a 1/3 of a bucket of mineral water

ha ha... expensive taste and all that!!

[Noony]

sbr definitely helps strengthen, but by adding it it makes staining more of a problem until you get a consistency you can work with
we usually have it a touch wetter by sounds of it, the sbr sends it off fairly quickly too we find

[lutonlagerlout]

reassuringly expensive mr noony :;):
i find the 3:1 plus sbr goes off nearly as fast as easipoint
but getting the consistency right is something only experience can dictate
too wet and you have had it
LLL

[Adrwilliams]

That all makes perfect sense - thanks very much. I'm a bit more confident now!

Cheers.

Adrian