Pointing problems with indian sandstone

[Phil52]

I'm in the middle of laying some paths and fancy patios with sandstone from Stonemarket. I can't seem to find a quick and efficient way of pointing the stuff-it seems to take for ever and isn't very good when it is finished.

I've tried the method on this site, using two trowels, but couldn't get on with it so I bought a pointing gun. This seems easier to fill the gaps but is still messy and it takes ages to clean the slabs alongside the mortar to avoid stains. I'm using a cloth and clean water after using a soft brush following use of the pointing tool. This was recommended by Stonemarket although it is not mentioned on this site. Is that because I'm too messy with the pointing or is it just a lousy time-consuming job for everyone? (It has just taken me a whole day to point a circular 'Sunflower' patio-there has to be a better way, surely?)

Also, even after this effort some of my slabs are stained by what looked like efflorescence alongside the joints. I assumed this would fade with time but it hasn't. Is this likely to be mortar stain and caused by rain after I had finished cleaning the joints? And how do I get rid-having tried wire brushing I seem to be marking the slabs' surface. I've read the warnings about brick acid so I'm reluctant to try it.

Any help would be greatly appreciated....

[remus]

Hi
A few points which may be of help to you. I am not using Sandstone from Stonemarket. My slabs are Marshall Saxon but the same tips should still help.
Forget Quick it takes a long time to point the slabs. From your comments i think that you have the mix to wet. when I started my patio I tried the two trowels with a to wet mix. It started to stain the slabs. I then went back to the main site and read this page http://www.pavingexpert.com/point04.htm tried again and have now done about 100sqm without any marks.
First it needs to be a dry day. I then water the joints with a can. Then a few hours later when the slabs are DRY then start to point them. When finised i cover with a sheet of poly over night.

hope this helps kevin

[Phil52]

Thanks for the advice Kevin. I had seen the technique you referred to but didn't use it as you seemed to need near-perfect conditions and the wet mortar method sounded easier. I can see now that your idea of wetting the joint first will solve part of the problem and brushing the semi-dry surplus off without it having stained sounds great.

One last question-is it safe for me to wire brush the stains off or is there a better way? (Having had rain on my last effort I have more stains to try to get rid of)

[lutonlagerlout]

oh dear another patio bites the dust
pointing can make or break a patio and it sounds like you have dropped a bollock on yours mate
i always wait for the right day (sometimes a week) then attack with a semi dry mix,by this it has to be just about wet enough to stick together but no wetter than that
i point the lot then brush off with a soft brush
then give a light shower of water 2-3 hours later
any sort of mechanical removal can cause you a few problems now mate,BTW i use a "marshaltown 92 wide pointing iron" they are good for patios cos of the width
good luck
LLL

[dig dug dan]

I have just pointed two patios of indian sandstone, each around 45sqm, using a pointing gun.
You must use soft sand, 3-1 mix, and plastisciser also.
I leave it in the mixer for abot 15mins, thn fill up the pointing guin, and squirt away. The trick however somes with jointing up, As lutonlaerlout suggests, using a pointing iron, but I amways leave it about an hour after "squirting", then joint it up. That way the excess doesn't stick to the slabs, and it can be swept off with a soft broom.

[slickboy]

Pointing properly is always a b*llache but the alternatives never match up long-term and pointing guns have their own problems. We use a 3/1 mix with enough water added to make it crumbly but not enough to stain the flags and we add a some SBR to the gauging water( as Tony MC suggests). We then either point it the day we lay the flags or the day after, otherwise we wet the joints a few hours before we point. Finally we use finger trowels and STRIKE THE JOINTS OFF HARD so they are compacted, me and my brother cannot stress this enough to our labourers! We use a petrol leaf blower to blow off all the crumbs afterwards. The trick is to get just enough water in so you can drag excess across the flags without leaving residue. It looks easy from the outside but there is more to it and there are LOADS of awful pointing jobs out there to prove it.

[Steve Harries]

I ended up using masking tape on the Indian Sandstone flags I've just finished laying (as suggested by Tony McC) after getting really pi**ed off with how easy it was to get mortar stains on the flags and how impossible it was to get them off again afterwards. It takes a long time to mask up properly if you have lots of small flags, and I felt like a real amateur (which I am), but it's your best bet for a relatively stain free finish. It doesn't make the actual pointing any less time consuming (I used the two trowel method) and you still have to be careful not to get the mortar too wet, or it will seep under the tape, but if it's your first time with Indian sandstone and you're only going to lay one patio, I think it's well worth the ache. Steve