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Posted: Sat Sep 22, 2012 9:00 pm
by jack101
i laid some sub base and compacted it with a ride on roller, some time has passed and i want to compact it again before laying the block paving on 6mm single sized stone. is it ok to use a pedestrian roller for the sub base and to compact the blocks after laying? if not, what are the reasons?
thanks
Posted: Sun Sep 23, 2012 1:04 am
by mickg
you need to use a vibrating plate to compact the paving blocks and you certainly could not use the vibrate on the roller or you may snap the blocks
likewise with the compacting of the 6mm laying course a vibrating plate is better than a roller
Posted: Mon Sep 24, 2012 8:54 am
by Tony McC
A roller is *ideal* for the sub-base, but the laying course and the blocks need slightly different treatment and a plate compactor is the tool to use.
With sub-base, we're looking to compact a reasonable depth of compressible aggregate, so a lot of mass and bit of vibration are ideal. For the laying course, the depth of aggregate and its compressibility is less, so although a roller could be used, it's not as nippy nor as manoeuvrable as a plate. When it comes to the blocks, all that is needed is vibration to settle the blocks by just a few millimteres into the laying course but more importantly, to rattle the jointing sand into place and get it tight into the joints. A roller cannot do this: it's a job for a plate.
Posted: Tue Oct 23, 2012 10:19 pm
by jack101
hi, i have a diesel forward/reverse compactor weighing about 150kg and i need to compact down the block paving. im worried the wacker is too powerfull for this job. the block is aura by brett 60mm and it really looks great, im worried about spoiling it. i used 6mm stone instead of sand and im really pleased with the results. it doesnt seem to compact as much as sand. is the wacker ok for this or should i get a smaller petrol one?
thanks
Posted: Tue Oct 23, 2012 10:24 pm
by jack101
also i didnt compact the laying course as it didnt seem necessary, even so the blocks only compact down about 8mm. thats why i would prefer lots of passes with a small wacker rather than one pass with a large one
Posted: Tue Oct 23, 2012 10:25 pm
by lutonlagerlout
why did you use 6mm stone?
is it permeable?
i wouldnt fancy the big diesel wacker on any new blocks
are you using kiln dried in the joints?
LLL
Posted: Tue Oct 23, 2012 10:30 pm
by Kuts
Don't suppose your in Leeds?
Passed a job today where some fellas are using a similar method
Posted: Wed Oct 24, 2012 3:18 am
by jack101
lutonlagerlout wrote:why did you use 6mm stone?
is it permeable?
i wouldnt fancy the big diesel wacker on any new blocks
are you using kiln dried in the joints?
LLL
I prefer the 6mm to the sharp sand we have. Yes we will be using kiln dried sand. The paving is not permeable.
Posted: Wed Oct 24, 2012 3:19 am
by jack101
Kuts wrote:Don't suppose your in Leeds?
Passed a job today where some fellas are using a similar method
No I'm not in leeds
Posted: Wed Oct 24, 2012 6:31 am
by lutonlagerlout
so wont the KDS migrate into the 6mm clean as there will be voids?
maybe tony mcC knows better than me but i thought 6mm clean was only for permeable paving?
cheers LLL
Posted: Wed Oct 24, 2012 6:47 am
by msh paving
lutonlagerlout wrote:so wont the KDS migrate into the 6mm clean as there will be voids?
maybe tony mcC knows better than me but i thought 6mm clean was only for permeable paving?
cheers LLL
In germany all they use for bedding layer is grit,and the kiln dry is washed in ,I cant see a problem there LLL
MSH 
Posted: Wed Oct 24, 2012 11:34 am
by Tony McC
The KDS *will* migrate into the 6mm clean over time, so you either accepot that you'll need to top-up every couple of months or so for the first 1-2 years, you give it a month or two then use a recognised stabiliser, or you endure until we get a warm. dry spell next spring and use a decent sealant.
Regarding compaction, with Aura I'd always recommend using a sole on the plate compactor, regardless of size. The heads of the Aura blocks are uneven so you get 'point compaction' which tends to result in spalling or crushing with a naked plate. If you can't get a neoprene sole, I've had excellent results using a sheet of "medium density non cross linked expanded polyethylene foam", as I now know it is called in the trade - it's the placky foam packaging stuff. And as one of our lurkers very helpfully pointed out to me in an email, you could also use those placky strips used as 'doors' for stacker trucks going into factories and warehouses.
Posted: Wed Oct 24, 2012 6:25 pm
by jack101
i didnt realise the sand would migrate into the stone, i will just have to top it up as required or maybe seal it when dry. i gave the wacker a try today with very good results. it bedded the blocks in really well and there was hardly any damage. no broken blocks. its a large area, not fully finished yet.
thanks for all the advice and information, wouldnt have been as good a job without it.