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.
>
> ][<
>
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