About a month ago I had an old patio relaid, it appeared to go alright until we had heavy rain and the slabs started moving. The guys that laid it came back after some dry whether and relaid some and pointed them up.
Problem now is the pointing is breaking up in small pieces when walked on and you can actually snap it between your fingers. The slabs aren't moving but some other pointing looks as if it will crack in the near future.
On contacting the guy he cannot understand why and has suggested I try a dry 3 sand/1 cement mix, brush it into the slabs and use a water can and sprinkler to see if it beds in. He will only come out if this doesn't take but he is a handyman who I feel isn't interested in the problem.
The slabs are normal flat ones, laid on a bed of sand. Will the mix he has suggested work as I thought he had used a bonding agent as well in his pointing mix.
My husband and I are both amateurs and would welcome any advice. Thanks. (sorry for long post)
If the slabs are laid on a bed of sand everything needs to be compacted well. It is much easier to lay them using a sharp / grit sand mix. The pointing is probably breaking up because there are too many cavities or it wasn't mixed very well or it dried out to fast when the water content drained into the sand. Although it sounds extreme, if you want the patio to stay in place for a few years, the best thing to do is most likely start again! Was your handyman cheap? There is an old saying, PAY CHEAP, PAY TWICE!
A dry mix is a waste of time and money. Unless you are absolutely, 120% sure there is NO movement whatsoever in the flags, a dry jointing mix will fail.
You need to figure out why the pointing done by this previous so-called contractor is breaking up. there are only two possible reasons:
1 - the pointing mix was too weak, not enough cement. Contractor's fault, get them back.
2 - the flags are wobbling slightly when trafficked. Contractor's fault, get them back.
For any contractor to suggest the client undertake essential remedial work is unacceptable. I suggest you mention Trading Standards when next you speak to this clown.
The fact that the paving moved following the heavy rain indicates that the sand wasn't compacted and definitely didn’t have cement mixed through, even the slightest amount would help hold the sand in place during the heavy rain.
The pointing breaking away is more likely down to the fact that there is still movement in the slabs. I would get them to lift one of the slabs and check out what preparation was carried out before laying the slabs.
