|Joist Spanning for Decking
Trex decking meets all applicable national model building codes. The joists must be spaced on center
according to the chart below. Be sure that the joists are level and plumb. Trex decking must span at
least three joists. For heavy items such as hot tubs, planters, etc., consult a local building engineer
or inspector for span recommendations. If you want to minimize the appearance of joists through the
spaces between the boards, paint the tops of your joists black.
Trex complies with major model building codes and has been evaluated by the International Code Council
For an Materials Safety Data Sheet (MSDS), please visit
|TREX DECKING SPAN CHART (On Center)
Light Duty Docks,
Residential/Day Care Playground
Boardwalks and Marinas
||100 psf = 4.8 kN/m2
|100 psf = 4.8 kN/m2
||200 psf = 9.5 kN/m2
|TREX RAILING SPAN CHART
||Maximum Railing Span for all Applications
||96" on center
You must gap Trex decking, both end-to-end and width-to-width. Gapping is necessary for drainage
and the slight thermal expansion and contraction of Trex decking boards. Gapping also allows for the shrinkage
of the wood joist system.
- ALWAYS follow Trex-recommended gapping guidelines.
- Maximum allowable perpendicular overhang for Trex is 4"for non-walking surfaces only.
- All decks require air circulation to keep them dry and looking good. To improve airflow, leave openings under
the decking or increase gapping to 3/8".
*- Temperature at installation.
|END-TO-END/END-TO-WIDTH AND ABUTTING GAP
*- Temperature at installation.
When you use the recommended hidden fasteners, the placement of the hidden fastener establishes
the designated gap size.
When installing fascia, gapping rules must apply.
The minimum required width-to-width gapping is 1/4". This is allowed for both hot and cold weather installations.
For docks and heavily wooded areas, Trex recommends a 3/8" gap as well. No gapping should ever exceed 1/2".
Gap Trex decking end-to-end, based upon the temperature at installation. See chart above.
Abutting Solid Objects
When decking is abutting a wall, you must gap it 1/4" - 1/2" depending upon the temperature at installation.
See chart above.
- Stair treads built with Trex meet requirements by the major national building codes. Consult
your local municipality for specific requirements.
- Fasten stair treads continuously across at least four stringers.
- See chart at right for center-to-center spacing of profiles.
- Dress the sides of stringers and risers with Trex fascia or trim for a finished look.
- 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 treads is not exceed 1/2".
*-For railings that are installed directly over stair treads, the stair treads must be larger
than 36" wide. Refer to local building code regulations for details prior to installing stairs and railings.
NOTE: Trex rails meet major building codes for use as a guardrail system. Local municipalities
may require a graspable handrail on stairways. Check with your local building code official for local requirements.
|MAXIMUM SPACING ON CENTER OF STAIR STRINGER
|Transcend 1" x 6"
Actual dimensions: .94" x 5.5"
|Select 1" x 6"
Actual dimensions: .82" x 5.5"
Decking Installation Page 3
Decking Installation Page 1
Trex Transcend Decking