NOTE: Delete these paragraphs unless loose-laid
ballasted system is specified. Normally specify
stone ballast for a ballasted system. Specify paver
ballast when:
1. There is danger of aggregate being drawn into
air intakes of jet aircraft.
2. There is danger of wind-blown aggregate
jeopardizing property and life safety.
3. In wind
zones exceeding 160 km/h (100 mph),
within 8 km
(5 miles) of coastline, within 457 m
(1500) feet
of open body of water, and on or
adjacent to
critical facilities such as hospitals.
3. Heavy foot traffic over large areas of roof is
expected.
**************************************************************************
[2.1.9.1
Stone Ballast
Smooth, rounded, river-washed stone graded in accordance with ASTM D 448,
sizes 1, 2, 24, 3, and 4, nominal 19 mm to 38 mm (3/4 inch to 1-1/2)
diameter, except as recommended otherwise by the roof membrane manufacturer
and approved by the Contracting Officer.
][2.1.9.2
Ballast Pavers
**************************************************************************
NOTE: Specify paver weight based on calculated wind
load conditions and ANSI/RMA/SPRI RP-4.
Lightweight interlocking paver ballast may be used
in lieu of heavier weight non-interlocking pavers in
wind zones in excess of 160 km/h (100 mph), within 8
km (5 miles) of coastline or within 457 m (1500
feet) of open body of water. Non-interlocking
pavers should weight not less than 88 kg per square
meter (18 pounds per square foot).
Elevated paver systems and pavers intended to
support pedestrian traffic, such as plaza decks or
observation decks, should be minimum 50 mm (2
inches) thick, 600 mm (24 inches) square, and
minimum 51,700 kPa (7500 psi) compressive strength.
Specify paver pedestrals for pavers without drainage
channels. Specify adjustable pedestals for systems
required to be elevated to a level plane such as a
plaza or observation deck.
**************************************************************************
Weather resistant, precast [interlocking] concrete roof pavers [with
drainage channels on the underside], and as recommended by the roof
membrane manufacturer. Pavers shall be minimum [20,680 kPa (3000
psi)][51,700 kPa (7500 psi)] compressive strength, weigh not less than [58
kg per square meter (12 pounds per square foot)] [88 kg per square meter
(18 pounds per square foot)] [_____], not less than [30 mm (1-1/4 inch)][50
SECTION 07530
Page 17
Previous Page
