Technical Specifications

13
SIDEWALL FINISHING
13
SIDEWALL FINISHING
13
SIDEWALL FINISHING
Exterior Finishes (also known as Coatings)
The CSSB recognizes these general types
of finishes:
There are a variety of paints, stains, and
preservative treatments available for Certi-label
Western Cedar sidewall products. Certi-label
sidewall products are available pre-finished,
(pre-primed or pre-stained) and natural
(unfinished).
Please note: A detailed product finishing
discussion is beyond the scope of this
manual; however, a brief overview is
presented below. It is critical to read the
instructions on the finish product’s container
as well as follow the finish manufacturer’s
directions. All areas of the world present
unique painting/staining challenges. Some of
the topics you should discuss with your
sidewall product manufacturer, finish
manufacturer, and professional contractor
include the following:
1. Product coverage
2. Surface preparation
3. Qualified finish contractors in your area
4. Certi-label Western Cedar moisture content
level recommended for your specific locale
5. Appropriateness of finish for Certi-label
Western Cedar sidewall products
6. Drying color versus sample chip color
7. Material Safety Data Sheet
8. Mildew resistance
9. UV resistance and water repellency
10. Exterior/Interior finish usage
11. Depth of finish penetration
12. Application method, including how to cover
all sides of product, mixing/stirring (to prevent
lap marks), temperature, brush versus spraying
tools, and recommended proper clean up and
disposal of all tools, brushes and rags. Talk to
your finish manufacturer if you have questions
about back-priming instructions for your
particular project.
13. Price. Do not be fooled by a low price. Better
quality brands tend to be more expensive. A
cheap finish will usually cost more in the long
run through quicker weathering, poorer
coverage and less pigment. Use only the highest
quality products from your finish manufacturer.
Quality finish manufacturers have technical
help lines you can call (some are toll-free).
Advice is also available via the Internet.
Transparent finishes (penetrating oil-based):
clear, allow natural grain to show through, may
also include paintable water repellant
preservatives. Such treatment can possibly,
depending upon the product, inhibit mildew
growth as well as rapid change in color due
to weathering.
Semi-transparent and semi-solid stains
(penetrating oil-based): have some pigment, but
allow some wood grain to show.
Paint or solid stain: provide opaque coverage,
allowing little to no wood grain to show.
Step 1: Factory or field applied oil-based, stain-
blocking primer on all surfaces.
Step 2: Field-applied top coat of highest quality
100% acrylic latex paint. This type of top coat is
more flexible and more resistant to blistering and
cracking. The best protection against extractive
bleeding is the application of an oil-based, stain-
blocking primer before the top coat is applied.
OR
Step 1: Factory or field applied oil-based, stain-
blocking primer on all surfaces.
Step 2: Field-applied oil-based or alkyd top coat.
CSSB member manufacturers do supply factory-
primed products. These products are usually
more cost-effective than on-site priming.
Use oil-based stains only. CSSB member
manufacturers can factory-apply a coat of semi-
transparent or semi-solid oil-based stain. This
process is usually more cost-effective than on-
site staining. Further enhancing the natural
durability of Certi-label Western Cedar shingles
and shakes, some CSSB members offer pass-
through finish warranties on their factory
finished sidewall shingles and shakes. These can
be further enhanced by application of a final,
field-applied top coat. Contact participating CSSB
members for details.
To hasten the weathering process, apply a
bleaching oil finish.
Generally finish products IMMEDIATELY after
installation PROVIDING that the moisture
content is appropriate for both the finish product
being used and your locale. If the finish is not
applied promptly, adhesion will be compromised
(unless additional surface preparation is
undertaken).
If you have installed a natural product
(unfinished), apply your finish before rain and
other moisture are absorbed. Ensure that you
account for high humidity concerns.
If you are using a pre-finished product (where
finish is applied at the manufacturing plant),
ensure that the product is thoroughly dried
before applying a top finish coat.
Certi-label Western Cedar Sidewall
Finishing Systems: Preferred Paint System
Less Durable Paint System
Stains
To Accelerate the Weathering Process
How Soon to Finish
In all instances drying time varies from region to
region. Excessive moisture will limit finish
adhesion. Check with your professional
contractor, finish manufacturer and/or sidewall
product manufacturer for assistance.
There are products that claim to be effective for
removing dirt, airborne pollution marks, mildew
and prior finishes. If you clean the surface prior
to finishing, ensure that it is allowed to dry to the
finish manufacturer's recommended moisture
content level before applying a new finish.
Contact your finish manufacturer for more
details.
Extractive bleeding is characterized by the
tannins in the wood being dissolved in moisture
and migrating to the surface of the product. Rain
will sometimes wash these stains away; however
if left to weather, the sun can cause
polymerization, thus requiring the addition of a
tannin blocker and new top coat of finish
(ensure proper surface preparation before
applying new top coat) once the moisture
problem has been solved. Compounds
containing oxalic acid appear to be the most
effective at removing extractive bleeding stains:
ensure you use proper safety precautions and
follow the oxalic acid compound manufacturer’s
application directions.
Extractive bleeding does not signify failure of the
applied finish, but instead is found in
applications where a source of moisture is
present. Extractive bleeding is not a
manufacturing defect nor is it a finish defect; it is
a natural phenomenon that occurs in
applications. Tannin blocking products help,
however, the CSSB does not provide any finish
warranty. Check with your sidewall product
manufacturer, finish manufacturer, and
professional contractor for more assistance.
The CSSB does not warrant this information
or instruction regarding finishes. If you see an
attractive job that has endured in your locale,
inquire about the type of finish used.
Certi-label
Surface Cleaning
Extractive Bleeding
Once
Western Cedar shingles and
shakes are pressure-impregnated treated you
must contact the treatment company to
determine if a finish, such as paint or stain, is
allowable. If there is any confusion
whatsoever it is highly recommended that
you contact both your sidewall product
manufacturer and the finish manufacturer.