Installation Guide
54
DESIGNER RAILING
HOW TO INSTALL STANDARD STAIR RAILING
TREX DESIGNER SERIES
NOTE: Trex rails meet major building codes for use as 
a guardrail system. Local municipalities may require a 
graspable handrail on stairways. Trex offers an ADA 
code-compliant handrail system. Check with your local 
building code officials for local requirements. 
Installing Posts for 
Stair Railing
1.   
I
n most cases, a 
railpost or post 
sleeve longer than 
39" (99.1 cm) is 
required for the lower 
stair rail sections 
to accommodate 
stair angle. Both top 
and bottom posts need to be installed on outside 
corners (nose) of stair treads. 
NOTE: Posts, post sleeve skirts, and post sleeves are 
installed per standard Designer railing instructions. 
See page 49.
Measuring and Cutting Railings 
2.   Determine length and angle of top and bottom rail. 
Set railings on the nose of the stair tread and mark 
line at each intersection.
  Cut rails on marks and place in position on 
  s
upports. (Supports can be made from scrap 
  material.)  
NOTE: Allow a minimum clearance of 1” (2.5 cm) from 
stair treads. 
N
O
TE: Check local building codes for railing height 
requirements.
Installing Bottom RSBs on Upper and Lower Posts
3.   Position bottom rail between posts and set to 
proper height from stair tread. Support on blocks 
cut from scrap materials. Mark both posts where 
underside of the bottom rail intersects.
4.   
P
osition one RSB centered on upper post with top 
of bracket aligned with mark on post, flat side 
D
O
W
N, a
nd secure with two 2" (5.1 cm) screws. 
Using a second RSB, turn upside down and 
interlock into bottom bracket on upper stair post.
5.   
P
osition one RSB centered on lower post with 
top of bracket aligned with mark on post, flat side 
UP, a
nd secure with two 2" (5.1 cm) screws. Using 
a second RSB, turn upside down and interlock 
into bottom bracket on lower stair post.
1
22
3
1
4
3
2
1
5
2
3
55
DESIGNER RAILING
Installing Top Rail RSBs on Upper and Lower 
Posts  
6.  Determine height of top rail from bottom rail and 
w
hile holding top rail in place, and parallel to bottom  
  rail, mark posts where underside of rail intersects. 
7. 
F
ollow Steps 4-5 to install top rail RSBs on upper 
  and lower posts. 
Measuring and Cutting Balusters
8.  Measure and cut balusters to proper height and 
  a
ngle of stairs. 
Assembling Rails with Baluster
9.  Insert and space balusters in top rails, then align 
b
ottom rails at parallel angle to top rails with  
  balusters spaced the same and in contact with 
b
ottom rail lip.
NOTE: Maximum spacing is 5" (12.7 cm) on center or 
3-5/8" (9.2 cm) between balusters.
Securing Balusters to Top and Bottom Rail
10.  Secure balusters to top rail with 2" (5.1 cm) 
16 gauge finishing nails through side of rail. Secure 
balusters to bottom rail with 2" (5.1 cm) finishing 
nails through underside of bottom rail. 
Attaching Foot Blocks
11.  Measure and determine angle to cut foot blocks. 
S
ecure with 2" (5.1 cm) 16 gauge finishing nails 
  through side of bottom rail.
NOTE: 2" (5.1 cm) screws can also be used. Pre-drilling 
would be required.
NOTE: Foot blocks are required every 18" (45.7 cm).
HOW TO INSTALL STANDARD STAIR RAILING/CONTINUED
TREX DESIGNER SERIES
8
2
2
1
1
9
3-5/8"
(9.2 cm)
10
2
2
18"
(45.7 cm)
11










