Posted: Mon Jul 19, 2010 8:16 pm
Hi,
I am in the process of laying Solhoffen-like irregular sandstone "crazy paving" on a patio. In fact, I am being greatly assisted by a neighbour who is a mason, as I have no idea what I am doing. (He's Portuguese, I'm Australian, and we live in France — you can imagine the scene...)
I don't know how much info you would need to answer the question I have, so I'll throw it out first, and fill in the details afterwards:
Some of the stones have not stuck down, and I would like to know what the best way to stick them back down is, before we get to pointing the lot.
Details:
We're laying the stones over a purpose-laid concrete slab, with what appears to be a "moist mix" bedding: grit sand and cement — I have been unable to determine the proportions, as my mason mate does everything by eye! If I had to guess, however, i would say that the ratio of cement to sand would be no more than 1:3 (or maybe 1:2.5). We lay and level about 2 sq. m of this bedding at a time (= 1 x 35kg bag of cement), then sprinkle it with cement (which immediately moistens into the surface), and proceed to position and tap down the individual stones. Working one mix takes us about 1.5 hours.
We're now about 1/3 of the way through (working roughly 3 hours per day — evenings — and not every day).
Today I noticed that a handful of the 100 or so stones we have already positioned have not adhered. I could simply lift them off the bedding, which is now quite hard and solid. Most of them seem to be solidly anchored, but just a few have not hung on at all.
Some of the stones are exfoliating (delaminating) a little, but this does not seem to be why they have not held on: all but one of the 9 that have come loose appear to have clean, stable surfaces.
So, the question (again): what would be the best way to stick these recalcitrant stones back down again, and I guess while I have your attention, I might also ask whether there is anything wrong with this whole approach? Should I expect more of them to give up in the future? Or will the jointing hold them down...?
Many thanks for your help, and well done on a superb website!
Colin
I am in the process of laying Solhoffen-like irregular sandstone "crazy paving" on a patio. In fact, I am being greatly assisted by a neighbour who is a mason, as I have no idea what I am doing. (He's Portuguese, I'm Australian, and we live in France — you can imagine the scene...)
I don't know how much info you would need to answer the question I have, so I'll throw it out first, and fill in the details afterwards:
Some of the stones have not stuck down, and I would like to know what the best way to stick them back down is, before we get to pointing the lot.
Details:
We're laying the stones over a purpose-laid concrete slab, with what appears to be a "moist mix" bedding: grit sand and cement — I have been unable to determine the proportions, as my mason mate does everything by eye! If I had to guess, however, i would say that the ratio of cement to sand would be no more than 1:3 (or maybe 1:2.5). We lay and level about 2 sq. m of this bedding at a time (= 1 x 35kg bag of cement), then sprinkle it with cement (which immediately moistens into the surface), and proceed to position and tap down the individual stones. Working one mix takes us about 1.5 hours.
We're now about 1/3 of the way through (working roughly 3 hours per day — evenings — and not every day).
Today I noticed that a handful of the 100 or so stones we have already positioned have not adhered. I could simply lift them off the bedding, which is now quite hard and solid. Most of them seem to be solidly anchored, but just a few have not hung on at all.
Some of the stones are exfoliating (delaminating) a little, but this does not seem to be why they have not held on: all but one of the 9 that have come loose appear to have clean, stable surfaces.
So, the question (again): what would be the best way to stick these recalcitrant stones back down again, and I guess while I have your attention, I might also ask whether there is anything wrong with this whole approach? Should I expect more of them to give up in the future? Or will the jointing hold them down...?
Many thanks for your help, and well done on a superb website!
Colin