| Lay out and cut the
Top Sheet strips to size in exactly the same way as the Underlay,
allowing a 50mm overhang and ensuring that the end laps and side
joints do not coincide with those of the Underlay.
The first Top Sheet should overhang
the roof drip edge by approximately 50mm.
Lay out the Top Sheet with the
release paper intact and cut the Top Sheet to the size required. Use
the same method of applying as for Underlay. The Top Sheet will be
laid in strips running with the joints staggered but not overlapping
any Underlay joint (see Fig. 10). At open roof edges, dress down the
vertical face by 50mm.
Where two ends of strip need to be
joined, overlap the ends by 75mm and ensure that all overlaps face
the same direction. All joins should be staggered so as no two
overlaps appear in the same position on adjacent strips.
|
Securely press the Top Sheet into any
angles that are encountered.
Repeat the procedure for all strips of Top Sheet until the deck area
is completely covered.
Sealing needed
You will notice that, at end laps
and detail work, the underside of the Top Sheet will not adhere very
well to the top, green slate mineral coating of the Top Sheet strips
now in place. Step 4 shows how to seal these joints, which should be
done as you install each piece of Top Sheet. The strip of Top Sheet
should be laid out with the selvedge edge to the middle or where the
next roll of felt is to come.
As with the Underlay and previously
laid Top Sheet, male sure that all overlaps go in the same
direction, that any joins are not over the joins in the Underlay and
no two joins are in the same line on different strips of Top Sheet.
Page 11 |
|
Apply a generous snaking 5mm bead of
Coldseal Lap Mastic to the topside of the lower Top Sheet surface,
across a band of 75mm or so. Using a spreader, spread the mastic
evenly over the surface of the Top Sheet (see Fig. 12).
Firmly press the top strip of Top
Sheet down onto the Lap Mastic to join the two surfaces together in
a watertight bond. |
First apply all the corner sections
pressing the top edge down firmly to compress the foam seals on to
the waterproof membrane, Holding firmly in position, gently hammer
the fixing pins through the pre-drilled slotted holes. Do not over
tighten the pins against the trim face.
Quicktrim Drip Edge.
Cut the drip edge trim to length
allowing a 3mm expansion gap between sections or corners. Tidy up
cut ends with fine sandpaper. Drill additional slotted fixing holes
as required to suit any cut length. Fix the drip edge trim over the
membrane, firmly pressing down to compress the foam seal on the
waterproof membrane. Holding firmly in position, drill a 2mm hole
through the back trim and gently hammer in the fixing pins. (see
Fig. 3) |
