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Posted: Tue Nov 03, 2009 10:58 am
by Bob_A
My PVA is made by BondLoc. Unfortunately they don't give any useful dosage rates on the packaging or their website when it comes to sand/cement.
I can't see it being critical so 100ml/25Kg seems a good starting point.
Cheers
Posted: Mon Dec 28, 2009 5:24 pm
by Bob_A
Apart from the jointing my patio is nearly finished.
Will probably leave the jointing until spring and use Rompox Easy.
On the whole the joints are pretty good but I was going to give them a quick rake just to be sure.
Was thinking of using a 115mm angle grinder but wasn't sure what to use with it, this is a one off so whatever I use doesn't need to last and needs to be cheap.
Was thinking of a cheap diamond blade
http://www.toolstation.com/shop....2
a mortar rake http://www.toolstation.com/shop....4
or a grinding discs
http://www.toolstation.com/shop....6
What do ya reckon?
Posted: Mon Dec 28, 2009 6:42 pm
by cookiewales
cheap one will be fine bob but be carefull and dont cut into slabs make two cuts it will fly out you only need to go 20 to 30 mm max preasure wash out before pointing rompox is good cheers cookie :p :;): :;): ps diamond blade is best
Edited By cookiewales on 1262025883
Posted: Mon Dec 28, 2009 9:29 pm
by Bob_A
Cheers
Got one last question ( I think!)
I'm going to use this for drainage
I was going to use SBR to make sure the flags for the mowing strip stay put.
What's the best way to use the SBR, do you add into the bedding mix or brush it on the back of the flags?
Cheers
Posted: Tue Dec 29, 2009 6:51 pm
by Tony McC
Either or both.
If you have fairly absorbent flags (sandstone or concrete) then dosing the mortar with the SBR is usually adequate, but with less permeable flagstones (slate, limestone and granite), it's often worth making up a slurry by mixing neat OPC with the SBR and daubing that on the underside of the flags as well as dosing the mortar.
Posted: Tue Dec 29, 2009 9:16 pm
by Bob_A
Thanks Tony.
Posted: Fri Jan 15, 2010 1:03 pm
by Bob_A
I mentioned I was going to use SBR and I've bought some from Toolstation. As I'm using sandstone then as Tony suggested dosing the mortar will probably be adequate.
Not sure what sort of quantity to add though. The makers data isn't that good.
http://www.cromar.uk.com/datasheet/SBRbond.pdf
Other makers of SBR don't give data for using it in the bedding layer for paving ether but they do suggest 10-15L per 50Kg cement for screeding.
Surely I don't need that much!
Was thinking summink like 1L per 25Kg bag of cement or am I way of the mark :p
Posted: Fri Jan 15, 2010 2:01 pm
by Tony McC
For a bond bridge, mix half-a-cup of SBR with enough cement to turn it into a pea-soup consistency slurry. Don;t make too much at once because it goes off and you're only painting it onto the undersides, so usage is slow.
For mixing mortar, 250ml per 5 litres of gauging water will usually be OK for general paving work: we'd quadruple that for bonding work, such as coping stones or step treads, etc.
Edited By Tony McC on 1263564114
Posted: Tue Aug 31, 2010 12:19 pm
by Bob_A
Rather than start a new thread I thought I’d resurrect this one.
My Indian Sandstone patio was finished a couple of months ago, well almost.
Got some joints I'm not cosmetically happy with so I'll redo them. Now while I'm at it...........
I have a handful of larger flags that click when I stamp hard on a corner.
For most people this would be acceptable, the obvious is to walk normal and don’t go deliberately stomping and stamping but that fact I know of this slight default might play on my mind.
The flags do not rock so I’d prefer not to lift them.
Looking back into the forum archives some respected contributors have said that with mixed success you can remove and clean out the joints around the suspect areas, very carefully pour in a slurry, let it set and then rejoint as usual.
Now I know this method isn't always succesful but my question is what should the slurry be made of?
Some of the old threads mention building sand/cement/water, some just neat cement and water.
What about sbr mixed with neat cement?
Cheers
Posted: Fri Sep 03, 2010 9:55 am
by Bob_A
A quick up date to anyone who might be interested.
I mixed cement and sbr together approximately 1:1 by volume.
Carefully poured it into the joints and cleaned up any spillage immediately (if not sooner)
Let it settle and topped up again (and again if necessary)
I'm amazed how well this works i've been stomping and stamping away and not one 'click'
Not sure if this is a good idea for rockers but I like I say it worked brilliantly in my case 
Will now repoint asap