Posted: Fri Jun 27, 2014 12:08 am
Hi,
Great website and used on a number of occasions but this is my first time using the forum.
I work as an Architect so I'm fairly switched on when it comes to building practices and concrete, but my expertise on landscaping and laying paving is limited, hence why I'm on here after any advice / opinions from you experts.
Basically I employed a Builder / friend to create a new patio area in my garden. It covers an area approx 18m x 4m. The slabs were laid on 100mm bed of compacted hardcore using a sand / cement mix and then filled with mortar.
On day 1 as I was leaving the house I saw the mix and thought that it looked a little dry (looked like a dry mix floor screed) but kept quiet as I wasn't the one laying the slabs and didn't want to tell someone how to do something they do every day of the week.
However, 3 days later and after letting the patio dry for a further 3 days, I ventured out. Literally the first slab I stepped on, rocked (and not in a good way). I walked up and down the entire patio and literally 80% of the slabs rocked (the worst offenders cracked the mortar join and pushed it out). I called the builder / friend and explained that they were loose, he came back (I was out) and from what I can tell only re-pointed the ones that had pushed the mortar out (we all know that this isn't solving the problem but is just a quick cure until I stand on it).
Getting slightly annoyed I call him back, this time I make sure I'm there. We discuss it and he tells me that due to the shear size of the patio, that the movement in the slabs is due to expansion / shrinkage of the concrete mix used to bed them. I give him the benefit of the doubt, he agrees to come back to fix the loose ones and I'm left with alarm bells ringing telling me that that is nonsense and that the problem is the mix was too dry and in reality it will all need to come up and to start again.
Before me and my friend have a proper falling out, do any of you have any useful advice as to whether you agree with me or if you think it could be down to expansion / shrinkage?
Thanks in advance!
Great website and used on a number of occasions but this is my first time using the forum.
I work as an Architect so I'm fairly switched on when it comes to building practices and concrete, but my expertise on landscaping and laying paving is limited, hence why I'm on here after any advice / opinions from you experts.
Basically I employed a Builder / friend to create a new patio area in my garden. It covers an area approx 18m x 4m. The slabs were laid on 100mm bed of compacted hardcore using a sand / cement mix and then filled with mortar.
On day 1 as I was leaving the house I saw the mix and thought that it looked a little dry (looked like a dry mix floor screed) but kept quiet as I wasn't the one laying the slabs and didn't want to tell someone how to do something they do every day of the week.
However, 3 days later and after letting the patio dry for a further 3 days, I ventured out. Literally the first slab I stepped on, rocked (and not in a good way). I walked up and down the entire patio and literally 80% of the slabs rocked (the worst offenders cracked the mortar join and pushed it out). I called the builder / friend and explained that they were loose, he came back (I was out) and from what I can tell only re-pointed the ones that had pushed the mortar out (we all know that this isn't solving the problem but is just a quick cure until I stand on it).
Getting slightly annoyed I call him back, this time I make sure I'm there. We discuss it and he tells me that due to the shear size of the patio, that the movement in the slabs is due to expansion / shrinkage of the concrete mix used to bed them. I give him the benefit of the doubt, he agrees to come back to fix the loose ones and I'm left with alarm bells ringing telling me that that is nonsense and that the problem is the mix was too dry and in reality it will all need to come up and to start again.
Before me and my friend have a proper falling out, do any of you have any useful advice as to whether you agree with me or if you think it could be down to expansion / shrinkage?
Thanks in advance!
