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For Refurbishment Only Applications
If applying directly to existing brickwork
/blockwork / render surface, the substrate must be brushed down to remove
any friable material, algae or lichen and fungicidal wash should then
be applied. Any ridges or protrusions should be removed and hollows filled
to provide a smooth surface.
For Refurbishment & New Build
Applications
Stabilising solution may be applied if required
to help improve adhesion and offer uniform suction.
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Install all beads and trims using approved WBS fixings at a maximum of 300mm
centres (depending on the substrate – please consult WBS technical
department for assistance).
Mix basecoat to a pliable consistency using approximately 4-5 litres of
clean water per 25kg bag of basecoat and dash receiver, Use approximately
5-7 litres of clean water per 25kg bag of Roughcast Render. A suitable
measuring bucket ensures the correct quantity and accuracy each time.
Ensure
that the basecoat is mixed thoroughly - it takes at least 10 minutes to
dissolve the powder additives. Note how the dryish mix becomes creamy
after several minutes. Mix will normally be slightly sticky.
Note: Renders with a high polymer content should
be left to stand for 10-15 minutes and be remixed to break the initial
set.
Do not
add anything to the mix other than clean water.
First Coat - Basecoat
Trowel
apply basecoat to substrate, dubbing out to a minimum of 8mm (or to architect's
specification) until a level surface is achieved.
Bed in
alkali resistant reinforcing mesh into top third of basecoat (if required),
ensuring that an overlap of a minimum of 75mm is achieved.
When basecoat is dry, apply additional stress patches and corner reinforcements
across all window and door openings at a 45° angle.
Tidy up base rails and profiles with a damp paint brush or similar to
ensure a professional finish.
Lightly scratch basecoat surface with a scratch comb to provide a key
for finishing coat.
Allow
24 hours curing time before further application, unless advised otherwise.
Second Coat - Coloured Dash Receiver
Trowel
apply coloured dash receiver to first layer of basecoat, in a single coat
4-6mm thick (or to architect's specification).
Allow
to firm but not set. A 16mm overall finish will avoid ghosting.
Dashing Coat - Coloured Roughcast
Always
turn a sufficient quantity of the final coat for a gable or large panel
into a bath or box to ensure that regularity of colour is achieved.
Do not
add any further water to the mix in the gauging box on the scaffold.
Throw
the Roughcast on to the surface of the Dash Receiver while the Dash Receiver
is still green, using a hand scoop or alternatively, an adjustable Tyrolean
gun may be used.
Do not
go over semi-cured areas to fill in misses, as this can lead to inconsistency
of colour. Do not apply water during set.
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Application Guide
Roughcast
APPLICATION GUIDE
