203-INST-UK-001 v1.0
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02 Aug 2022
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Page 10 of 21
Step 1
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Install, Trim and Finish the Roofing Underlay (Felt or Membrane)
Cut underlay that covers the hole to leave 50mm flap on all edges. Trim and then fold the underlay back on itself as shown. The
underlay should be folded back on the structure that will support the product. If desired, a layer of silicone can be used to seal the
cut edge down.
If a sunken installation is used, the secondary fillet (not supplied) should be underneath the underlay.
Figure 3
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Roofing underlay installed and prepared
Step 2
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Install the Cill Tilting Fillet
Install a tilting fillet as shown (not supplied) - Glazing Vision recommends that a hardwood or treated softwood fillet is used. The
length of the Cill Tilting Fillet should be at least the length of the external width of the product and have a minimum 5° fall over the
fillet. Consider the distance required between the cill of the product and the fillet (figure 4
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gap A), and the height of the fillet. Fix
the fillet to the rafters.
Figure 4
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Cill tilting fillet installed
The purpose of the tilting fillet is to support the flashing at the cill of the product. Lead used for flashing must be
supported or it will sag over time, allowing water to pool or even to run underneath the tiling to the sides of the
product.
Cut edge of underlay
folded back
Cill fillet (primary)
Gap A
