Installation Guide
24
HOW TO INSTALL DECKING
Stringer
1” x 8" Riser
11" min. depth
1/4" - 3/8" gapping
Fasten treads to
all stringers
3/4" max. overhang
See chart below
Riser removed for clarity
36" minimum width – 4 stringers are required
Above 36" width – 5 stringers are required
Spanning Requirements for Trex
®
Stairs
Note: English measurements are shown. Convert to metric measurements if necessary.
Stairs
Stairway Detail
» Stair treads built with Trex meet requirements of
the major national building codes. Consult your local
municipality for specific requirements.
» Fasten stair treads continuously across at least
four stringers.
» See chart (to the right) for center-to-center spacing
of profiles.
» Dress the sides of the stringers and risers with trim or
Trex fascia for a finished look.
» When installing risers, use two screws per
every stringer.
» Fascia fasteners can only be used if fascia boards
are being used for risers. If deck boards are used,
recommended composite deck screws must be used
(glue is not required for this application).
» Most model building codes require the stair treads to
be constructed under the following requirements:
› Stairways must be at least 36" wide*
› Stair treads must be at least 11" deep
» Gapping between Trex boards on stair treads must
be 1/4"–3/8".
» The overhang of the stair tread is not to exceed 3/4".
* For railings that are installed directly over stair treads, the stair
treads may need to be larger than 36" wide. Refer to local building
code regulations for details prior to installing stairs and railings.
NOTES:
» Trex rails meet all major building codes for use as a
guardrail system. Local municipalities may require a
graspable handrail on stairways. Check with your local
building code ocial for local requirements. See Trex
ADA Handrail System in the Trex product catalog.
Maximum Spacing on Center of Stair Stringer
Transcend 1" x 6"
12"
Select, Enhance (scalloped bottom),
1" x 6"
9"
Transcend & Select 2" x 6"
12"