][3.2.3.4
Ballasted Membrane Application
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NOTE: Delete this paragraph unless a loose-laid
ballasted application is specified.
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Layout membrane and side lap adjoining sheets minimum 100 mm (4 inches) and
according to membrane manufacturer's printed instructions. Allow for
sufficient membrane to form proper membrane terminations. Ensure membrane
is free of wrinkles and ridges in the installation. Form field lap splices
or seams as specified and of width required by the membrane manufacturer's
installation instructions. Check seams to ensure continuous seal before
proceeding with further work. Apply continuous lap sealant to all adhesive
formed seams and all cut edges of reinforced membrane materials.
]3.2.4
Tape Seams / Lap Splices
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NOTE: Seam tape shall be the primary seaming, or
lap splice, technique. Adhesive seaming in the
field of the roof shall only be specified with
Government approval. Adhesive seaming of flashing
in limited areas may be required where tapes are
difficult to apply.
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Field form seams, or lap splices, with seam tape in accordance with
membrane manufacturer's printed instructions and as specified. Clean and
prime mating surfaces in the seam area. After primer has dried or set in
accordance with membrane manufacturer's instructions, apply seam tape to
bottom membrane and roll with a 75 mm to 100 mm (3 inch to 4 inch) wide
smooth silicone or steel hand roller, or other manufacturer approved
rolling device, to ensure full contact and adhesion of tape to bottom
membrane. Tape end laps shall be minimum 25 mm (1 inch). Roll top
membrane into position to check for proper overlap and alignment. Remove
release paper from top of seam tape and form seam splice. Ensure top
membrane contact with seam tape as release paper is removed. Roll the
closed seam with a smooth silicone or steel hand roller, rolling first
across the width of the seam then along the entire length, being careful
not to damage the membrane. Apply minimum 225 mm (9 inch) long strip of
membrane-backed flashing tape over T-intersections of roof membrane. Roll
tape to ensure full adhesion and seal over T-joint.
[3.2.5
Adhesive Seams / Lap Splices
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NOTE: Include the bracketed option in the first
sentence as the norm. Government approval required
for adhesive formed seams in the field of the roof.
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Field-applied adhesive formed seams shall only be used [in flashing areas]
where approved by the membrane manufacturer and the Contracting Officer.
Adhesive formed seams shall not be used for field of roof membrane
seaming[, except as approved by the membrane manufacturer and the
Contracting Officer]. Thoroughly and completely clean mating surfaces of
materials throughout the lap area. Remove all dirt, dust, and contaminants
and allow to dry. Apply primer as recommended by the membrane
SECTION 07530
Page 24
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