Indian sandstone - brick acid - re-point - Help

[framer]

I have just finished laying a patio of indian sandstone at about 8 m2,unfortunatly i stumbled across this excellent site after i had laid it and now i realise some of the tips i have been given are wrong.
I layed the flag on a wet mix of mortar which was on a bed of grit sand,this does not seem too bad,now i have learnt it should have been done on a dry mix.
I have also pointed using a very wet mix taking no care were the mortar went,i asked the man at the builders yard if a dry mix would be sufficient for pointing,he said "why when you can use wet,it is natural stone just chisel it off or use acid,it will not fade" !!
I then proceeded to use brick acid to remove the mortar stains,i think i have been lucky as i only have one large rusty lookin flag and a couple of smaller multicoloured flags...

My questions are :-

is there any way to rid the acid stain or do they need replacing?

if they need replacing,would the best method be to grind out the joints,lift the flag and knock the mortar off with a brick hammer?

i was also thinking of re-pointing the lot so i can point with a dye,as it look so much bettter,would this be done using a grinder to grind out the joint?

thanks in advance...

[Rich H]

Bad luck with the brick acid. There is no cure I'm afraid, the stain is caused by a chemical reaction within the rock which causes precipitation of the iron salts which are normally bound in.

You'll need the grinder to remove the stained slab(s) and mortar beneath and replace as required. If you just repoint the new slab try to get the mix as close to the original as possible, only not so wet that you can't keep it off the slabs (if you make the mix dry and strike it in it will look different to the wet mix even if the proportions of sand and cement are identical). If you decide to repoint all the joints, you might end up ripping the lot up in an effort to get the joints clean, although 8 sq.m is small so maybe that's not such a bad idea?

[Rich H]

Tony has a section at the end of this page:

http://www.pavingexpert.com/stonpv01.htm

From which this picture is lifted:

[framer]

cheers rich

yes i think i will check how easy the mortar comes away from the underside of the stained flag,if it is quite easy i will do them all

[seasider]

Where did you learn you should of laid the flags on a "dry mix"?

[Rich H]

http://www.pavingexpert.com/layflag3.htm#ten2one

Dry doesn't mean bone-dry, really semi-day: just a little or no added water in the case of sand which is delivered damp.

[seasider]

So why semi-dry over a wet mix?

[Sharpia]

I've have also just laid an Indian Sandstone Patio, and have mortar stains on the edge of the slabs from where I was over eager with the watering can rose when pointing in the joints.

Reading the articles about the dangers of Acid brick cleaners can you recommend a suitable way of removing the mortar. Brushing (for a long time !) does seem to work but it'll take me about six months to do it this way.

Also the stones have now a dusty appearance, and as mentioned many times on this excellent site look much better when wet. Again though I want to clean the stones before I seal it with Thompsons Patio Sealer to bring out the colour, unless anyone else has experience of a better product ?

Thanks
Ian

[IanMelb]

Again though I want to clean the stones before I seal it with Thompsons Patio Sealer

I've read some not great things on this site about Thompson's Patio Sealer (I believe it has been referred to as Patio Ruiner ??? )

For instance:

http://ext.pavingexpert.com/cgi-bin....thomson

[Tony McC]

Keep away from the Patio Ruiner! For some reason, I get more complaints about it going wrong than all other sealants combined. It seems to be incredibly sensitive to *any* residual moisture.

[Rich H]

seasider - semi-dry is the only way I know that you can get most of the slab in contact with most of the bedding layer. The more water you add, the more cement you need and the stiffer the mix is, therefore the more difficult to consolidate completely under the slab. If you go wetter still, with more cement, the slab tends to float, is difficult to get level and can bugger it's neighbours when you tap it.

I still add half a bucket of water to the mix, especially at this time of year.

[lutonlagerlout]

its weird rich ,i get no problems at all with a wet mix as long as its on type 1
i tried it once on a concrete base and it was a nightmare,but the type 1 sucks a lot of the excess water out really fast
my auld fella used to do dry mix and i never rated it,always odd rockers etc
each to his own
LLL

[Rich H]

You're right. My Polish slabber prefers a mix with a slump like brick mortar and 4:1. What I do know is that he gets more rockers than me, much to his annoyance

[lutonlagerlout]

i cant get a rocker with a wet mix??
still as long as it doesnt fall to bits whatever suits
LLL

[stella]

I cant find the answer. What is the best way to get the grey film of staining( from pointing) off my newly laid patio. It was done by a landscape contractor and I would like it corrected before I pay him. The paving is multi coloured sandstone, and now looks dull grey. I'd appreciate your advice. Thanks