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Posted: Fri Oct 01, 2010 4:50 pm
by Al Jardin
Looking forward to it. Thanks LSP.
Al
Posted: Fri Oct 01, 2010 6:26 pm
by GB_Groundworks
London Stone Paving wrote:Just read that blog. Really good stuff. Calibrations got to be better for everybody. I also think that calibrated stone will have a flatter surface as it needs to be flatter to go through the calibrating machine. Still think 22mm is too thin though. We bit the bullet and are going for 25mm. Taking our first delivery in about two weeks and from here on in we will only be ordering 25mm indian stone. We'll have to put the prices up a touch but so be it
3mm make all the difference does it? I'm sceptical myself, bedding and sub base more important than an extra 3mm
I'd be interested to see some scientific load and strength testing
Posted: Fri Oct 01, 2010 7:44 pm
by ispaving
ive been bringing in calibrated stone now for nearly two years. Dont sell the natural finish at all, although it can be sourced.
As i have direct family links with quarries and logistics companies in india it is more affordable than most people think.
Calibration is the way to go, the machinary and skill required eliminates any child labour issues that have been propaganded by big companies as a selling point more than anything else.
Posted: Fri Oct 01, 2010 9:43 pm
by London Stone Paving
I've been having this discussion with LLL and he is equally sceptical about the difference 3mm will make.
Its not just the chance of breakage during installation but also the chance of breaking during haulage, moved around site etc etc +. Also would you trust 22mm on a driveway?
The following calculation demonstrates the difference in strength between 22mm & 25mm stone. Obviously the calculation is not 100% because stone is a natural material with different physical characteristics from one piece to the next.
The strength of the material is roughly proportional to the cube of the depth. Here goes:
25/22 = 1.136
Therefore 25mm stone is 13.6% thicker than 22mm stone
1.136 x 1.136 x 1.136 = 1.446
Therefore in general terms a piece of 25mm stone is 44.6% stronger than a piece of 22mm stone.
Giles you are spot on though when you say the most important thing is the bed. It absolutely is
but
Before the stone is finally settled down on a full, evenly laid bed of mortar it is at risk of damage from any of the following:
Haulage
Storage and moving round site
Installation
Also what if someone does use spots, or does not work on a full bed of mortar by choice or by accident?
Posted: Sat Oct 02, 2010 7:56 am
by Mikey_C
i presume with the calibrated there is "less" chance of some idiot wrecking someone's patio by laying it upside down :p
Posted: Sat Oct 02, 2010 8:06 am
by lutonlagerlout
of course when side is covered in grooves it makes it pretty obvious :;):
i estimate there is a 20% increase in laying speed with calibrated ,less faffing around with the bedding
LLL
Posted: Sat Oct 02, 2010 9:11 am
by London Stone Paving
You would hope so Mikey, but you never know.
We had a client once who really liked the fosssils in the fossil mint. We were very new to the game at this point and really eager to please, so we went through all these crates of stone to find all slabs with fossils on. We got a call a week later from a very irate client asking where all the fossils were. I was scatching my head, not being able to work out what had happened.
Went round to have a look for myself and the builder had laid the stone upside down. Could not believe it. To make things worse he had also laid it on a concrete base. Can you imagine that for a balls up. It was one of the worst i've seen
Posted: Sat Oct 02, 2010 9:29 am
by GB_Groundworks
So 43% stronger for 3mm? Not doubting your math but I'm going to test this, got a few pieces left of the polished fossil mint we used on the big house. Ranges in size from 10mm to 40mm. I'll do some load tests on the stone.
I won't lay Indian stone on drives anyway, there's some lads doing one near our yard. Probably 35sq metres. 2 bulk bags of mot!!! Laying on bricklaying mortar, least there using the older non calibrated slabs.
Edited By GB_Groundworks on 1286009126
Posted: Sat Oct 02, 2010 9:37 am
by seanandruby
Did a 600 drop beam once that was 3ml higher than it should of been. Would'nt let us scabble it incase it weakened the beam. ???