This method relies on each flag having a bed prepared for it individually.
A bed is prepared, the flag is laid and then the next bed prepared
and so on.
method is more common used with larger flags, where handling and
maneuverability is a major concern, with natural stone flags, where
there can be differences in flag thickness between adjacent units.
The flagstones should be laid directly onto to a mortar mix
of 4 parts sand (class M) and 1 part cement approximately 20 - 40
mm thick. There must not be any voids under
thickness of natural stone flags makes screed bedding
This method requires a screed bed to be prepared before placing
the flags. A relatively large area can be screeded in advance and
the flags placed one after the other directly onto the bed.
obviously more efficient than the individual bedding method, this
method is only suitable for the smaller flags, generally those less
than 600x600mm, which are small and light enough to be manhandled
onto a screeded bed. It is essential that the flags be of a constant
thickness, hence only the small element paving and wet-press manufactured
patio flags are suitable candidates.
thickness of Calibrated Brazilian flags makes screed bedding
Preparation and sub-base
is not normally required for a path or patio unless there is concern
regarding the suitability of the sub-grade. However, any low spots
can be filled with crushed hardcore, crushed stone or compacted
bedding material. The surface needs to be dug off to a depth of
approx. 90mm, assuming no sub-base is required. The depth of dig
can be calculated as...
depth of flagstones + 35-50mm bed + any sub-base required)
driveway or other heavy use, the sub-base layer is the load bearing
layer. A full concrete bed (CBM4) is the best solution, combining
sub-base and bedding in one and should be at least 100mm thick,
minimum. For public footpaths, this may sometimes be reduced to
75mm, or increased to 150mm or more to give added protection to
Use a spade or large trowel to level out the bedding material,
which should have the top 15-25mm loosened to allow the flag to
be bedded down - this is usually achieved by 'rippling' the bedding
surface, creating small troughs and peaks with the blade of a
trowel. The bed should be 5-8mm high to allow for consolidation.
Make the prepared bed spread 100mm or so further than the flag
will cover - it is better to have the bed to big than too small,
leaving an edge of the flag unsupported
an individual bed
Ideally, the bedding should be 25-50mm thick. Less than 25mm renders
it almost impossible to settle the flag, while more than 50mm
makes for uncertain compaction. Adjust the level of the sub-layers
rather than use less than 25mm or more than 50mm of bedding.
note for Sandstone and Travertine the random patterns may vary
from those of slate. We endeavor to put more larger slabs in,
as a proportion to make laying easier and reduce the number of
Grout lines. Please advise if you need a particular pattern and
we can quote you accordingly
We recommend that all Sandstone, Quartzite, Travertine and Slate
be sealed with an impregnator or similar. This will not only enhance
colour and prevent staining, it will reduce water absorption and
reduce incidence of algae growth
Picures and advice taken
from website www.pavingexpert.com