First of all - great website ! I have almost finished laying 100 m2 of block paving and I have found this website to be invaluable and have followed the guidelines on this website almost to the letter.
I noticed a quite varaition in the thickness of the paviors as I was laying them. Some were anything between 5 mm thicker than some others. Has anyone alse had experience of this ? I used Marshalls Driveline 50 range. I have also used two of the Driveline circles but there doesn't appear to be the same problem. :p
Block thicknesses - Vraiation in pavior thickness
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Nigel Walker
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Good old Marshalls Driveline 50 !!!!
It does not surprise me that you are experiencing problems with these blocks.
I have stopped using Marshalls blocks (unless a client specifies them)
The main problem i had was last November time. The Driveline 50 blocks were not only different thickness but different sizes, so the herringbone pattern wasnt working. After laying about 1m in length of blocks they were 5-6mm out of square. 5m along and they were 25mm out. The 45 degree herringbone would not work
I contaced Marshalls and they were no help whatsoever. They insist that their products have a +- 5mm tolerence, They were not prepared to do anything about it. So I stopped using their products
I now use Tobermore paviors for about 90% of my work.
No problems at all.
The difference in thickness is not really that much of a problem. When you compact the paviors they should all bed down to the same height. If you find you have some stubborn ones which wont compact to the same level, remove the offending blocks - loosen the bedding sand, maybe remove a small bit of bedding and replace the block, sand and compact.
The problem is when the blocks are different widths and lengths. Problems !!!
Nigel
It does not surprise me that you are experiencing problems with these blocks.
I have stopped using Marshalls blocks (unless a client specifies them)
The main problem i had was last November time. The Driveline 50 blocks were not only different thickness but different sizes, so the herringbone pattern wasnt working. After laying about 1m in length of blocks they were 5-6mm out of square. 5m along and they were 25mm out. The 45 degree herringbone would not work
I contaced Marshalls and they were no help whatsoever. They insist that their products have a +- 5mm tolerence, They were not prepared to do anything about it. So I stopped using their products
I now use Tobermore paviors for about 90% of my work.
No problems at all.
The difference in thickness is not really that much of a problem. When you compact the paviors they should all bed down to the same height. If you find you have some stubborn ones which wont compact to the same level, remove the offending blocks - loosen the bedding sand, maybe remove a small bit of bedding and replace the block, sand and compact.
The problem is when the blocks are different widths and lengths. Problems !!!
Nigel
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Tony McC
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I wonder if it was just a bad batch, Nigel? A contractor mate of mine in West Lancashire was telling me more or less exactly the same thing just a week or so ago - Blocks that were not dimensionally accurate in plan, although he reckoned they were summat like 210x100, which is probably an exaggeration.
It's unusual for blocks that are not "in ratio" to be allowed to leave the factory, but I know from my own experienmce that it does happen, and it's a bloody huge pain in the arse when it does, as there's no sensible way of rectifying: the only viable solution is to chuck them out and order afresh.
The only way blocks can be 'out' in the plan dimensions is for the mould to be damaged, worn or incorrectly manufactured. It's not all that uncommon to find blocks that vary in thickness by ± 3mm (so there could be a 6mm diff between two adjacent blocks) because of the way the concrete is pressed during manufacture, and the way we lay block, on a partially compacted bed of griot sand, helps accommodate these inevitable variatuions. However, any discrepancy of more than ±1mm in the plan sizes, and I'd send the blocks back, regardless of what the manufacturer says....and if they don't want to take them back: well, there's plenty other manufacturers wanting my business.
It's unusual for blocks that are not "in ratio" to be allowed to leave the factory, but I know from my own experienmce that it does happen, and it's a bloody huge pain in the arse when it does, as there's no sensible way of rectifying: the only viable solution is to chuck them out and order afresh.
The only way blocks can be 'out' in the plan dimensions is for the mould to be damaged, worn or incorrectly manufactured. It's not all that uncommon to find blocks that vary in thickness by ± 3mm (so there could be a 6mm diff between two adjacent blocks) because of the way the concrete is pressed during manufacture, and the way we lay block, on a partially compacted bed of griot sand, helps accommodate these inevitable variatuions. However, any discrepancy of more than ±1mm in the plan sizes, and I'd send the blocks back, regardless of what the manufacturer says....and if they don't want to take them back: well, there's plenty other manufacturers wanting my business.
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Ian Rutherford 1
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Tony McC
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