Historic Preservation - Technical Procedures
Surface Preparation For Painting Wood
Hspg Prepared For Nps - Sero
Wood And Plastics
Surface Preparation For Painting Wood
SURFACE PREPARATION FOR PAINTING WOOD
A. This procedure includes guidance on preparing wood
surfaces for painting.
B. Wood surfaces scheduled to be refinished with a
transparent finish shall have existing coating stripped
and sanded prior to application of new coatings.
C. Wood surfaces scheduled to be finished with an opaque
finish (see 06300-01-S) shall either be stripped or
sanded as required to produce a smooth substrate for
application of the new coatings.
D. For guidance on paint removal from wood, see 06400-07-R
"Chemically Removing Paint From Wood Features",
06400-02-S "Supplemental Guidelines for Removing Paint
from Interior and Exterior Wood Surfaces" and 06400-09-R
"Removing Paint From Wood Features Using Thermal
E. For general information on paint for wood, see 06300-01-S.
F. For additional information on the history, properties and
uses of paint, see 09900-01-S.
G. See 09900-07-S for general guidelines on painting
interior and exterior surfaces.
A. American International Tool Industries, Inc.
1116-B Park Avenue
Cranston, Rhode Island 02910
800/932-5872 or 401/942-7855
B. Benjamin Moore and Co.
51 Chestnut Ridge Road
Montvale, NJ 07645
C. The Sherwin-Williams Company
101 Prospect Ave. N.W.
Cleveland, OH 44101
NOTE: Chemical products are sometimes sold under a common
name. This usually means that the substance is not as pure as
the same chemical sold under its chemical name. The grade of
purity of common name substances, however, is usually adequate
for stain removal work, and these products should be purchased
when available, as they tend to be less expensive. Common
names are indicated below by an asterisk (*).
A. Paste Wood Filler: Solvent-based, air-drying, paste-type
wood filler for use on open-grain wood on interior wood
surfaces such as "Benwood Paste Wood Filler" (Benjamin
Moore and Co.), "Sher-Wood Fast-Dry Filler" (The Sherwin-
Williams Co.), or approved equal.
B. Trisodium Phosphate:
NOTE: THIS CHEMICAL IS BANNED IN SOME STATES SUCH AS
CALIFORNIA. REGULATORY INFORMATION AS WELL AS
ALTERNATIVE OR EQUIVALENT CHEMICALS MAY BE REQUESTED FROM
THE ENVIRONMENTAL PROTECTION AGENCY (EPA) REGIONAL OFFICE
AND/OR THE STATE OFFICE OF ENVIRONMENTAL QUALITY.
1. Strong base-type powdered cleaning material sold
under brand names.
2. Other chemical or common names include Sodium
Orthophosphate; Tribasic sodium phosphate;
Trisodium orthophosphate; TSP*; Phosphate of soda*;
(also sold under brand names such as).
3. Potential Hazards: CORROSIVE TO FLESH.
4. Available from chemical supply house, grocery store
or supermarket or hardware store.
Non-ammoniated detergent such as "Tide"
Liquid bleach containing 5% sodium hypochlorite (common
C. Boiled Linseed Oil
D. Turpentine - clean and clear so that it will not
adversely affect the texture or durability of the paint.
E. Caulking Compound (in order of recommended usage):
1. Polyurethanes - easily workable; paintable; 15-20
year life span; limited availability.
2. Polysulfides - slow drying; can be sanded and
painted; highly elastic; limited availability.
3. Butyls - paintable but cannot be sanded; 7-10 year
4. Silicones - some can be painted but generally not
5. Acrylic Latex - for exterior work, their use is
best left to tight, narrow joints; short life span
especially when compared to polysulfides and
F. Clean, potable water
A. Sanding blocks, sanding sponges, orbital sander, all with
a variety of grits.
B. Sanding vacuum such as "S344 Sander Vac" (American
International Tool Industries, Inc.), or approved equal.
C. Stiff, natural and nylon bristle brushes
A. Protection: Spot-prime exposed ferrous metals such as
nails on or in contact with surfaces to be painted with
water-based paints. Use a suitable corrosion-inhibiting
primer capable of preventing flash rusting and compatible
with the coating being used.
B. Surface Preparation:
1. Lightly sand all surfaces, either by hand or with
an orbital sander, using fine grade sandpaper.
CAUTION: WORKERS SHOULD USE PROTECTIVE CLOTHING
AND RESPIRATORS FOR PROTECTION AGAINST
CONTAMINATION WITH LEAD DUST.
NOTE: CHEMICAL REMOVERS MAY RAISE THE GRAIN OF THE
WOOD. SUCH ROUGH FIBERS WILL WEAKEN THE PAINT FILM
CAUSING PREMATURE PAINT FAILURE. THERMAL METHODS
OFTEN LEAVE BEHIND HARD PARTICLES OF PAINT RESIDUE
WHICH ALSO NEED TO BE REMOVED TO ENSURE A SMOOTH
2. If only limited paint removal is required, feather
edges of sound paint to provide a smooth transition
between the old and the new paint. Use either hand
methods or an orbital sander.
NOTE: BELT SANDERS SHOULD ONLY BE USED BY
EXPERIENCED PERSONNEL. THEY WORK VERY QUICKLY AND
IT IS EASY TO DAMAGE THE WOOD SUBSTRATE IF THEY ARE
NOT USED CAREFULLY.
NOTE: SANDING DUST MAY CONTAIN LEAD; USE SANDING
EQUIPMENT EQUIPPED WITH A SANDING VACUUM TO PREVENT
LEAD DUST FROM GETTING INTO THE AIR. FOLLOW OTHER
REGULATIONS PROVIDED BY THE EPA REGIONAL OFFICE
AND/OR THE STATE OFFICE OF ENVIRONMENTAL QUALITY
CONCERNING THE HANDLING OF LEAD-BASE PAINT.
3. Scrape and clean small, dry, seasoned knots and
apply a thin coat of white shellac or other
recommended knot sealer before application of putty
or plastic wood filler to finish surface
imperfections. Sand smooth when dried.
4. Fill all nail holes, voids, surface defects, etc.
prior to refinishing.
a. Putty stop holes where nails are set and
screws countersunk on all finished woodwork.
b. Include puttying or spackling repairs to
voids, cracks, minor splits, and similar
surface defects in finished woodwork to be
painted or stain-varnish finished.
5. Recondition wood to ensure a tight bond between the
new paint and the wood. Wood that is not
reconditioned after paint removal is often left
very dry and, therefore, may absorb too much of the
binder in the paint resulting in poor binding of
the prime coat.
a. Mix 2 parts boiled linseed oil with 1 part
b. Apply liberally with a brush and allow to dry.
c. Repeat as necessary until dry surface has a
6. If all paint has not been removed, wash the painted
surfaces to remove all grease, dirt and mildew, and
to insure adequate adhesion of the prime coat.
a. Wash dirt and grease using a solution of 3
quarts warm water mixed with 2/3 cup trisodium
phosphate (TSP) and 1/2 cup non-ammoniated
b. If mildew is a problem add 1 quart of liquid
bleach. For stubborn mildew, straight bleach
may be necessary. Scrub surfaces with a
medium bristle brush and rinse with clean,
clear water. Make sure the surface is
completely rinsed before painting.
NOTE: WHEN TSP IS MIXED WITH WATER IT FORMS FREE
ALKALI. THIS FREE ALKALI WILL CAUSE OIL-BASED
PAINTS TO BECOME SOAPY SO THAT THEY WILL NOT STICK
TO THE SUBSTRATE. RINSE THOROUGHLY WITH CLEAN
WATER BEFORE PROCEEDING. (CHECK LABEL FOR
INGREDIENTS. SODIUM CARBONATES FOUND IN SOME
DETERGENTS HAVE SIMILAR PROBLEMS.)
CAUTION: DO NOT MIX AMMONIA WITH CHLORINE
BLEACHES, A POISONOUS GAS WILL RESULT! DO NOT USE
BLEACH ON BIRD DROPPINGS.
7. Apply a Water Repellent (WR) or Water Repellant
Preservative (WRP) (See 06310-01-S and 06310-01-P
for guidance on preparation and application).
NOTE: THIS TREATMENT IS RECOMMENDED FOR EXTERIOR
ITEMS SUBJECT TO EXTREME WEATHERING CONDITIONS, OR
WHICH ARE ESPECIALLY DRY OR MAY HAVE BEEN
CONSOLIDATED. SOME OF THESE EXTERIOR ITEMS MAY
INCLUDE WINDOWS, CORNICES, OR OTHER ITEMS WHICH MAY
HAVE HAD SEVERELY PEELING PAINT AND EXPOSED WOOD
FOR A NUMBER OF YEARS.
NOTE: ALL UNPAINTED WOOD WHICH IS TO BE REPAINTED
USUALLY BENEFITS FROM THE APPLICATION OF EITHER A
WR OR A WRP.
8. Caulk any end grain wood subject to water
infiltration. Also, caulk where wood trim pieces
or door and window frames meet wall surfaces.
9. Wood trim which has been removed, or new pieces to
be installed, may be "back-primed" or painted along
the end grain for additional moisture-proofing.
When transparent finish is required, backprime with
END OF SECTION