TANDEM
®
SYSTEM
–
11
BUILDING A RETAINING WALL
TYPICAL CROSS-SECTION AND INSTALLATION PATTERN –
WALL WITH MIX OF LAFITT OR MELVILLE TANDEM 90 AND 180 UNITS
A Straight capping unit (connected to drains)
90 mm × 305 mm × 400 mm
(3 9/16" × 12" × 15 3/4")
B Structural units
90 mm or 180 mm × 155 mm × variable
(3 9/16" or 7 1/16" × 6 1/8" × variable)
C Veneer units
90 mm or 180 mm × 67 mm × variable
(3 9/16" or 7 1/16" × 2 5/8" × variable)
D 100-mm perforated drain (4") connected to drains
E Geotextile membrane
F 0-20 mm (0-3/4") compacted aggregate base
G Min . buried depth of 150 mm (6")
H 20 mm (3/4") clean stone
I Starter unit
90 mm × 200 mm × 400 mm
(3 9/16" × 7 7/8" × 15 3/4")
INSTALLATION PATTERN
MODULAR PATTERN:
75% TANDEM 90 UNITS
25% TANDEM 180 UNITS
A
D
I
C
B
H
E
F
G
0° or 9°
300 mm
(12") min .
150 mm (6") min .
900 mm (36") max
300 mm (12") min .