10
Assembly
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Code 4 lead flashing to be fitted at roof level as per Building Regulations. We
recommend that you scorch a 5-10mm deep channel into the outer surface of the
casings and fold in the top edge of the flashing.
Finish the outer surface of the casings above the roof with 2 part waterproof render.
The recommended mix is 1:2:5-6 cement:lime:sand for the undercoats. 1:2:8-9
cement:lime:sand for the final coat. The number of coats required will depend upon
the degree of exposure, generally a two coat mix is acceptable. The mix may vary due
to climate conditions, the thickness of any one coat should not exceed 15mm, and each
subsequent coat should be reduced by approximately 3mm. Isokern concrete capping
for render to be lip glued onto the last casing.
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Code 4
lead flashing
(not supplied)
Capping
for render
Waterproof
render
10mm gap
for ventilation
under Top Ring
At the top of the chimney, insert
capping fixings into the four corner
holes of the casing
Fix capping using the bolts
provided.
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27
Fit aluminium top ring by pushing
the steel prongs into the outside of
the inner flue block.
Make sure it’s a tight fit and that
approx. 10mm gap remains from
the underside edge of the top ring
to the capping.
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High tensile steel reinforcement rods will be required for all chimneys with a height
that exceeds 1.4m above the roof line, 1.1m if the wind speed exceeds 44ms.
These rods are available from Isokern and must be grouted (1:3 cement/sand) into the
holes provided in the outer casings. You must start the rods at least the same height
below the roof as what’s above, please check with our technical department.
Reinforcement
rods
