CR-21 Landscapes and Irrigation
questions fully solved & updated
2025
What thickness in millimeters of pavers is used for
residences?
A. .6
B. .5
C. .75
D. 63.5
D. 63.5
Brick (paving brick, pavers). Rectangular fired clay
brick with typical dimensions of 4 inches x 8 inches
x 2.5 inches thick. Available in a range of colors,
paving bricks have no mortar holes and an average
strength of approximately 5,000 PSI.
What is the length of a standard concrete block
including the mortar joint?
A. 8 inches
B. 10 inches
C. 12 inches
,D. 16 inches
D. 16 inches
Sizes are usually given in their nominal
dimensions.A unit measuring 7 5/8" wide, 7 5/8"
high, and 15 5/8"long is known as an 8" x 8" x 16"
unit. The mortar jointis intended to be 3/8" to fit
the modular design basedon a 4" module.
When should you seal the bottom of a piece of
wood fencing?
A. If water pools under them
B. when within 5 feet of a sprinkler head
C. If there is less than 2 inches of clearance from
the ground.
D. If it touches the earth
D. If it touches the earth
If the boards have to touch the earth, seal the
board ends before you install them.
How is transplant shock avoided?
A. NEED HELP WITH THIS CHOICE
B. Anti transpirants
,C. increase water
D. Fertilize
B. Anti transpirants
Antitranspirants, also called antidesiccants, are
chemicals that reduce the amount of water plants
lose through transpiration. Antitranspirants are
useful because excessive water loss can result in
transplant shock. They normally act either to
induce closing of the stomata or to cover the
stomata with a water-impermeable coating.
A trench has been prepared for a gray water
irrigation lines, according to the International
Residential Code, what shall be the minimum depth
of the filter material beneath the perforated line?
A. 12 inches
B. 3 inches
C. 8 inches
D. 6 inches
D. 6 inches
Not less than 6 inches in depth of aggregate,
ranging in size from 1/2 to 2-1/2 inches (12.7 mm
, to 64 mm), shall be laid into the trench below the
distribution piping elevation.
A CR-21 licensee may install residential misting
systems under what PSI?
A. 1000 psi
B. 120 psi
C. 90 psi
D. 500 psi
A. 1000 psi
HARDSCAPING AND IRRIGATION SYSTEMS This
classification allows the licensee to install, alter,
and repair:
Residential outdoor misting systems. Free standing
or attached to existing appurtenance, not more
than 1000 PSI.
Blue Stake uses orange to mark which of the
following?
A. Gas
B. Electric
C. Fiber Optics, Cable, Phone
D. Sewer
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