Posted: Mon Apr 23, 2007 6:54 am
I finally finished my patio, and pointed the joints yesterday.
I originally started to point the joints with slightly damp mortar, the mix was just right with regards to water - as it was not runny, but instead like butter.
However, as i have 200 slabs, and as it took me around 15-20 minutes just to do one slab, i decided it was too time consuming and that i would use the brush in method instead - so i disgarded the damp mortar i mixed up and mixed up some more mortar without adding any water for the brush in mix.
Now, i have had disasterous results using this method around 6 years ago, whereby i used a wet mix to brush into sandstone slabs and ended up the following day with SEVERE staining and spent nearly 1 month afterwards using acid and cleaning materials trying to clean them but it ruined the surface.
This time however, i made sure that it was bone dry with no water added, and although it was a pain to get it all off the slabs afterwards - as i used building sand, and a 2:1 mix (as the building sand bags looked bigger than the cement bag) and it was so so powdery - i seemed to manage to get it all off in the end.
However - this is my problem, this morning i have checked, and although there is no visible staining, the cement still hasn't gone off (i finished brushing in around 18:00hrs yesterday) and i'm worried that if it rains it may all pour over the slabs and stain????
Also - i've noticed that although no cement is visible, if i touch the surface of the slab with my finger then i am left with a white powdery residue? Could this amount cause staining?
I really don't want these slabs to stain - so please can somebody help me out here and advise me what to do?
Thank you in advance..
I originally started to point the joints with slightly damp mortar, the mix was just right with regards to water - as it was not runny, but instead like butter.
However, as i have 200 slabs, and as it took me around 15-20 minutes just to do one slab, i decided it was too time consuming and that i would use the brush in method instead - so i disgarded the damp mortar i mixed up and mixed up some more mortar without adding any water for the brush in mix.
Now, i have had disasterous results using this method around 6 years ago, whereby i used a wet mix to brush into sandstone slabs and ended up the following day with SEVERE staining and spent nearly 1 month afterwards using acid and cleaning materials trying to clean them but it ruined the surface.
This time however, i made sure that it was bone dry with no water added, and although it was a pain to get it all off the slabs afterwards - as i used building sand, and a 2:1 mix (as the building sand bags looked bigger than the cement bag) and it was so so powdery - i seemed to manage to get it all off in the end.
However - this is my problem, this morning i have checked, and although there is no visible staining, the cement still hasn't gone off (i finished brushing in around 18:00hrs yesterday) and i'm worried that if it rains it may all pour over the slabs and stain????
Also - i've noticed that although no cement is visible, if i touch the surface of the slab with my finger then i am left with a white powdery residue? Could this amount cause staining?
I really don't want these slabs to stain - so please can somebody help me out here and advise me what to do?
Thank you in advance..