The mosaic is pre-fabricated at the workshop, and can be compared
to a giant jigsaw puzzle with pieces of very varied shape. Installing
a mosaic is similar to laying large-scale stone slabs, except that
the extra depth of the mosaic and the different shapes make the
job more challenging. We provide a site plan which shows the shape
of each section; these are numbered to enable the jigsaw puzzle
to be put together with ease.
Slabs average 750x750mm. Depth: 75mm. Maximum
weight: 150 kg.
All slabs can be conveniently handled and laid by two men.
A base should be provided for the mosaic,
with layers of stone or concrete suitable for its intended usage.
Detailed recommendations are available on request. A border of stone
or sets should be planned, to protect the edges.
THE CASTING PROCESS
Fabricating the mosaic can be described as
a “reverse” technique; (like an “upside-down”
cake). Each section has an individually-constructed mould into which
the pebbles are placed with their top-side down, & packed vertically
within the mould. Like icebergs, there is a lot more of each pebble
embedded in the slab than is visible on the surface. This technique
ensures that the finished surface feels comfortably flat underfoot.
first stage of casting uses a non-shrink cementitious grout, which
penetrates the tiny gaps between the pebbles and ensures a very
hard final surface. The slab is completed with concrete (3:2:1),
tamped and vibrated. The slabs are cured under polythene wraps for
4 weeks to attain maximum strength.
The mosaic is delivered to site packed vertically on palettes. Maggy
Howarth or another craftsman from Cobblestone Designs undertakes
to supervise the installation continuously.
mosaic slabs are bedded on mortar on to a previously prepared site.
Since it is more economical to use local labour already on site
to lay the slabs we usually estimate for supervision only.Then
we complete the job personally by grouting the joints between the
slabs of mosaic, using the same non-shrink grout which was used
in the casting process.Altogether, the time taken for the installation
varies from 1 day (for a 3-metre mosaic) to 5 days (6 -metre mosaic)
Correctly installed, the pebble mosaic is immensely strong &
durable. Occasional brushing with a stiff brush will remove dirt
which may collect between pebbles. Mosaics which have become dirty
may be restored to nearoriginal condition by use of a cold water