Posted: Thu Jul 06, 2006 4:12 pm
Hi,
This is my first post, although I've browsed quite a lot as a guest for advice on a driveway (successfully completed), and a concrete slab patio (problems!).
I employed a local contractor, and laboured to reduce costs, so I was onsite the whole time. He's done good work previously (driveway, fencing), is open about costing etc. Basically, I trust him.
Patio is 450mm slabs, about 20sq m. He dug out to a depth of 3-4in, levelled for drainage etc, and laid on a wet concrete mix (shovelled in dry and watered in situ, doing a couple of slabs at a time). Joints were brush-filled after with 4:1 drymix mortar and watered in with a fine spray.
He'd recommended a wet mix for solidity - didn't mention any possible problem with "window-framing" but that doesn't seem to be a problem anyway.
Big problem is that several weeks later, a large proportion of the slabs were noticeably rocking, to the extent that the mortar joints are breaking and lifting out. When i noticed the first one, I thought it was a 1-off (as did he) and he replaced it. We're both worried about the apparent extent of the problem now - I don't need another week of hassle, and he doesn't need a week of unpaid work to fix it!
I decided to leave it for now so we can have the use of the patio over the summer, but eventually something needs to be done. Any hints on what may have gone wrong and how to fix it? I stress that i don't have a problem with the contractor over this (unless he later refuses to play ball of course!), and he seems genuinely concerned and at a loss to explain what's going on. He only works locally, has a very good reputation as a fair man and quality worker, so its not in his interests to upset a local customer who's given him a lot of work over the years!
He replaced the first slab by breaking out the concrete below and relaying in wet mix. That one seems solid a couple of weeks on. I really don't want to have to break up the whole thing and redo. If the bedding slab is structurally intact, is there a way relay the loose slabs on it with minimal height increase?
Thanks
Drew
This is my first post, although I've browsed quite a lot as a guest for advice on a driveway (successfully completed), and a concrete slab patio (problems!).
I employed a local contractor, and laboured to reduce costs, so I was onsite the whole time. He's done good work previously (driveway, fencing), is open about costing etc. Basically, I trust him.
Patio is 450mm slabs, about 20sq m. He dug out to a depth of 3-4in, levelled for drainage etc, and laid on a wet concrete mix (shovelled in dry and watered in situ, doing a couple of slabs at a time). Joints were brush-filled after with 4:1 drymix mortar and watered in with a fine spray.
He'd recommended a wet mix for solidity - didn't mention any possible problem with "window-framing" but that doesn't seem to be a problem anyway.
Big problem is that several weeks later, a large proportion of the slabs were noticeably rocking, to the extent that the mortar joints are breaking and lifting out. When i noticed the first one, I thought it was a 1-off (as did he) and he replaced it. We're both worried about the apparent extent of the problem now - I don't need another week of hassle, and he doesn't need a week of unpaid work to fix it!
I decided to leave it for now so we can have the use of the patio over the summer, but eventually something needs to be done. Any hints on what may have gone wrong and how to fix it? I stress that i don't have a problem with the contractor over this (unless he later refuses to play ball of course!), and he seems genuinely concerned and at a loss to explain what's going on. He only works locally, has a very good reputation as a fair man and quality worker, so its not in his interests to upset a local customer who's given him a lot of work over the years!
He replaced the first slab by breaking out the concrete below and relaying in wet mix. That one seems solid a couple of weeks on. I really don't want to have to break up the whole thing and redo. If the bedding slab is structurally intact, is there a way relay the loose slabs on it with minimal height increase?
Thanks
Drew
