Don't forget to tamp the sand real good. I noticed that the recent drought expanded my brick walk requiring more sand. I've heard the is a sticky sand used now that prevents grass from growing between the bricks.

Larry2

---- Gabriel Orgrease <[log in to unmask]> wrote: 
> John Walsh wrote:
> >
> > The areal dimensions of the flags are important.  I'm a geologist 
> > rather than an engineer so I judge rocks by how hard it is to bust 'em 
> > with my 16" Estwing sledge.  It's a lot harder to crack through a 2" 
> > thick rock when it's only four inches rather than four feet across.  
> > But seriously, the 4" thickness seems a bit excessive even for large 
> > flags.  I'll defer to the engineers but my hammer experience tells me 
> > that a good quality bluestone on a sound and stable substrate should 
> > be able to be placed at a 2" thickness for flags up to 4' x 4'.
> >
> John,
> 
> I agree w/ your hammer test. Where I think it comes in a problem in the 
> thickness for a sidewalk though is the 'sound and stable substrate' as 
> what I have noticed is that a majority of masons will say that they know 
> how to set stone but have no clue really what they are dealing with. 
> Then when it comes to trucks driving over sidewalks we may be dealing 
> with more than a hammer blow. For casual pedestrian traffic, say a back 
> yard patio, 1" bluestone set well is often sufficient. A traditional 
> bluestone sidewalk would have been flags at least 4" thick set on a dirt 
> bed (nowadays sand or fine crushed stone)... but I cannot see any 
> building code letting that happen with a public sidewalk... what I see 
> being done is a concrete pad with then a mortar setting bed for the 
> stone. Then not done well -- there being a pride issue that almost any 
> mason if asked will want to say they know how to do the job, even if all 
> they really know is CMU. A friend of mine is currently dealing with a 
> landscape mason who installed a large quantity of bluestone church 
> property sidewalk in a very suspect manner. Other than that I would 
> agree on the 2" for 4 x 4.
> 
> The large bluestone slab sidewalks, that folks are attempting to 
> replicate the look of, as they were set in dirt the individual stones 
> could range in thickness, one corner being 4", the other corner 6". 
> These stones were quarried with less use of powered equipment than 
> nowadays, squared up by hand rather than by saw. Since it was dirt 
> underneath the dirt did not cost anything and could be moved around as 
> needed to set one side of the stone in plane. I never set these 
> sidewalks new, but I have straightened them out as they tend over time 
> to have tree root or frost heave... thus as we are maintenance adverse 
> in the modern world, and nobody can tolerate a crooked line or a lawsuit 
> from tripping hazards, nobody wants to have a sidewalk that needs 
> maintenance. Also as fabrication and quarry technologies have developed, 
> along with standardization of materials dimensions, there is a greater 
> need for power equipment (energy consumption) to cut stone to closer 
> tolerances, but also the ability to get more utility out of a mass of 
> stone. What would have at one time been a 4-6" thickness of stone now 
> becomes 4" of concrete (concrete that took energy to produce... Portland 
> cement, crushed stone quarry, explosives, truck to deliver, barge etc) 
> with mortar (more energy expended) to set a thinner cut stone. Possibly 
> a more complex chain of employment goes into building a sidewalk 
> nowadays than in the past? The good news, as if it is good news, is that 
> we are conserving on the world supply of suitable building stone which 
> means that for every hole in the ground there is a more efficient use of 
> the natural resource. That is if we do not take into consideration 
> energy consumption in comparison to the traditional thick sidewalk and 
> the contemporary faux version. As far as I know bluestone quarries are 
> geared for the dimensions that they now produce and that if you want 
> anything out of the current standard range it is a custom order. There 
> is also the transport issue, as a thinner cut stone makes for more 
> square footage of flagging on a pallet. There is the getting the stone 
> onto the truck, let alone out of the ground, and palletized stones 
> stacked on edge are a lot easier to get onto and off the truck, with 
> more stone surface on the load. Let alone a 2" 4 x 4  can be handled by 
> one person, or two depending, whereas a 4" thick stone, particularly if 
> it needs to be set in mortar, will have the masons cussing at whomever 
> thought up the idea. So, IMHO if one wants to set thicker stone it 
> should probably be best done in dirt/sand and the lead masons checked to 
> make sure they actually understand traditional building technologies. 
> The sidewalk set on a dirt/sand bed will last for a really long time if 
> it is maintained.
> 
> ][<
> 
> --
> To terminate puerile preservation prattling among pals and the
> uncoffee-ed, or to change your settings, go to:
> <http://listserv.icors.org/archives/bullamanka-pinheads.html>
> 
>

--
To terminate puerile preservation prattling among pals and the
uncoffee-ed, or to change your settings, go to:
<http://listserv.icors.org/archives/bullamanka-pinheads.html>