Specifying Cedar Decking
SPECIFYING
CEDAR DECKING
A deck made with Western Red Cedar, one of the
world’s most beautiful woods, is apt to be one of
the best looking decks in the neighborhood. But
Western Red Cedar decks have much more going
for them than good looks alone. Extending living
space to the outdoors, integrating home and land-
scape, making use of damp or uneven terrain and
giving a contemporary look to a traditionally-styled
home are just a few of the ways that decks make
life a little better.
Once the decision is made to build a deck, the
choice of decking material is just as important as
good design and quality construction. In today’s
environmentally conscious society, the natural
choice is Western Red Cedar.
All wood used in the outdoors must be protected
against decay and insect attack.Not only is Western
Red Cedar one of the few woods with its own
preservative oils, its freedom from pitch and resin
makes it an excellent base for protective coatings.
And cedar has other natural qualities that make it
the best choice for decking. It is the most stable of
British Columbia’s softwoods,so Western Red Cedar
decks stay flat and straight and resist checking.
Western Red Cedar decks are firm but resilient
underfoot, not hard and unyielding. The wood is
light weight, easily worked and ideal for almost all
types of finishes. It has an elegance that comple-
ments any architectural style and a beauty that
blends into all landscapes.
Whatever the reasons for building a deck, there is
just one natural choice of decking material.
Available in a wide range of grades and sizes, and
price-competitive with lesser materials, Western
Red Cedar decks are the beautiful, practical, long-
lasting complement to any home.
2
SPECIFYING WESTERN RED CEDAR
DECKING
To simplify specification, decking is now available in four
grade categories offered exclusively by members of the
Western Red Cedar Lumber Association.These few easily
understood categories of decking provide a choice of
quality clear grades or rustic knotty grades for outdoor
decks of any style and budget.
The following information is required when specifying
decking:
Specification Information Sample
Required Specification
Species:
Western Red Cedar WRCLA Western
Red Cedar
Size:
Specify the size 5/4 x 6
of decking.
Grade:
The grade of decking WRCLA Custom Clear
®
governs its overall quality.
Refer to following pages for
available grades.
Moisture Content:
Specify whether the Unseasoned
product is to be
seasoned on unseasoned.
Quantity:
Express in linear feet. 1000
Western
Red Cedar
DECKS
3
4
CLEAR GRADES OF WRCLA WESTERN RED CEDAR DECKING
Grade Description
The ultimate in durability and
appearance.Its fine grained
heartwood appearance will meet
the needs of the most demanding
clients.All aspects of
manufacturing and quality
control are performed to the
highest standards of the lumber
industry.Architect Clear decking
should be specified when only
the best will suffice.This
exclusive product is usually
manufactured to individual order.
Available seasoned or
unseasoned.
A quality product that combines
the stability and durability of
Western Red Cedar with a
sophisticated clear appearance
that will please the most
discriminating taste.Its finely
machined surface shows limited
characteristics which do not
detract from its natural good
looks.Custom Clear decking can
be used directly on the job and is
a natural for custom residences
and other applications where fine
woodwork is desired.Available
seasoned or unseasoned.
Thickness Width Span
(in.) (in.)
Grade Category
(in.)
1-1/4 4
All clear grade
16
categories
1-1/4 4
All knotty grade
12
categories
1-1/4 6
All clear and knotty
16
grade categories
24
All clear and knotty
24
grade categories
26
All clear and knotty
24
grade categories
Architect Clear
®
Custom Clear
®
SIZES AND SPANS OF WESTERN RED
CEDAR DECKING
WRCLA Western Red Cedar decking is available in a selec-
tion of thicknesses, widths and lengths as shown in the
table opposite.
Maximum spans for decking shown in the table are based
on a continuous beam with two equal spans and a con-
centrated load of 220 lb at the center of one span (see
illustration on page 5).The true span of the decking board
is used, taking into account the thickness of the support-
ing joist beneath it. Wet end-use conditions and unsea-
soned (green) lumber sizes are assumed.
5
KNOTTY GRADES OF WRCLA WESTERN RED CEDAR DECKING
Grade Description
Rustic charm at its best.Durable,
well manufactured Western Red
Cedar decking that comes ready
to use.This sound and tight-
knotted decking limits both the
size and quality of characteristics
to meet the highest buyer
expectations.The smooth,skip-
free dressing over the entire face
makes it the ideal deck surface.
The top choice where the natural
beauty and lasting charm of a
knotty deck are desired.Available
seasoned or unseasoned.
Widely used by homeowners and
builders,this category of knotty
decking combines the high
manufacturing standards required
for deckboards with a hole-free
knotty appearance.This category
limits the size and quality of
characteristics to provide an
economical and enjoyable knotty
deck.Custom Knotty decking
may be applied as received and is
a natural choice for home deck
builders,residential builders,and
commercial applications where a
durable knotty material is desired.
Available unseasoned only.
To help figure the amount of decking needed for a project, use
the following linear footage calculator:
To Cover 100 Square Feet of Deck
Nominal Size (in.) Linear Feet
1-1/4 x 4 325
2 x 4 325
1-1/4 x 6 211
2 x 6 211
Architect Knotty
®
Custom Knotty
®
Span
Span
Continuous Beam
Over Two Spans
220lb
Concentrated
Load at Centre
FASTENERS
Nails
Hot-dipped galvanized, aluminum and stain-
less steel nails are all corrosion-resistant
and all can be used to nail Western Red
Cedar.Other types of nails,such as elec-
tro-plated, are not recommended.They
can rust and disintegrate and react
adversely with the natural preservative oils
present in cedar, resulting in stains and
streaks. Copper nails also react with cedar
and should not be used.
Stainless steel is the best choice but hot-
dipped galvanized is the most widely used and economical.
Use 3 in. (10d) nails to fasten decking with a nominal thick-
ness of 2 in.and 2-1/2 in. (8d) nails on decking with nominal
thickness of 1-1/4 in.This will allow for nail penetration of
approximately 1-1/2 in. into deck joists for secure, trouble-
free construction (length may be reduced by 1/4 in.if ring or
spiral shank nails are used).Deck boards 2 in.wide need one
nail per joist while 4 in. and wider decking requires two per
joist.To prevent wood from splitting, use thin shanked nails
with blunt points.
Screws
Screws can also be used to fasten decks.
Double hot-dipped galvanized screws can
be used, however, stainless steel screws are
recommended. For most applications a 304
(18-8) grade provides adequate corrosion
resistance. For decks exposed to salt air,
use 316 grade. Screws must be long enough
to penetrate 1 in. into support members.
Penetration of 1-1/2 in. is required for structural
components.
Blind Fastening
Systems
These systems create
a fastener-free deck
surface.They employ
metal clips and/or
joist top brackets that
fasten the sides or
bottom of the deck
board to the joists so
that no fasteners are
visible.
6
FINISHING
Although cedar is naturally durable, a surface coat is recom-
mended to protect the wood and extend its service life.
Cedar accepts a wide range of stains and other coatings
and whichever is selected should be a good quality product
recommended by a paint or building supply dealer. When
selecting a finish coat, make sure it contains the following:
Water repellent
Fungicide/mildewcide
Protection against ultra violet (UV) light
Penetrating oil-based products, particularly those containing
pigments, are recommended for cedar. Pigments provide
increased UV protection. Note that decks require products
specifically formulated to withstand the abrasive effects of
foot traffic. Use of varnishes or other types of film forming
coatings are not recommended for cedar decks.These coat-
ings can crack and peel and once applied are difficult
to remove. Also, avoid non-drying coats as these
often feel sticky underfoot and can result in
stains on interior floor coverings.
BUILDING AND MAINTENANCE
TIPS
Space deck boards apart to allow proper
water drainage.A deck that dries after
wetting will last longer than one that
stays damp.
Keep the deck free of leaf, pine needle and other debris
build-ups.These can retain water and clog drainage channels
resulting in a deck that cannot drain and dry properly after
wetting.
Moisture and debris can collect where butt joints occur
over joists.To create drainage, butt decking boards between
double joists as shown, leaving a 1/8 in. space between the
ends of the boards.
Move planters, benches and other deck accessories
from time to time to allow the deck under them to dry
thoroughly.
Deck Board
Joist
Full Length
Fastener
7
The Western Red Cedar Lumber Association (WRCLA)
does not warrant the accuracy of the information herein.
The WRCLA,its directors,officers,employees,servants and
agents shall not be responsible or liable for any cause of
action, loss, damage, injury or death in any way connected
with the information herein even though such cause of
action, loss, damage, injury or death arises from the negli-
gence or default of the WRCLA, its directors, officers,
employees, servants or agents.
Wester
T
he Western Red Cedar Lumber Association (WRCLA)
is a non-profit trade association representing quality
producers of Western Red Cedar lumber products in
British Columbia, Canada and the US Pacific Northwest
states. Association members are dedicated to producing
quality sidings, decking, paneling, outdoor and other
specialty cedar products in a wide range of sizes and
grades. The WRCLA is committed to providing the
construction industry with information about WRCLA
member products,their specification, and proper use.
Distributed by: Bear Creek Lumber
Printed in Canada
Copyright 1993
93-494 Revised May 2000
