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Historic Preservation - Technical Procedures

Spectitle:

Applying A Semi-Transparent Or Opaque Stain To Wood

Procedure code:

0630003R

Source:

Developed For Hspg (Nps - Sero)

Division:

Wood And Plastics

Section:

Wood Treatment

Last Modified:

01/23/2015

Details:

Applying A Semi-Transparent Or Opaque Stain To Wood



APPLYING A SEMI-TRANSPARENT OR OPAQUE STAIN TO WOOD

PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on applying a semi-
         transparent or opaque stain to wood surfaces.  This
         coating will prolong the service life of wood and provide
         some protection against agents of deterioration.

         NOTE:  IF THE WOOD WAS ORIGINALLY FINISHED WITH A FULL
         BODY PAINT, IT SHOULD BE REPAINTED RATHER THAN STAINED,
         AS THE VISUAL APPEARANCE OF STAIN IS NOT COMPATIBLE WITH
         THAT OF PAINT.  SOME STAINS, HOWEVER, MAY BE SUITABLE
         REPLACEMENTS FOR WHITEWASH PAINT.  CONSULT THE RHPO FOR
         GUIDANCE AND RECOMMENDATIONS.

    B.   Natural causes of wood deterioration include decay,
         ultraviolet degradation, insect infestation and excess
         moisture.

    C.   Some types of problems resulting from the weathering
         process include:

         1.   Fungi and/or mildew growth

         2.   Warped boards

         3.   Loose fasteners

         4.   Changes in surface texture resulting in cracks and
              checks

    D.   In addition to opaque paints, various so-called "natural"
         finishes and colored stains provide this necessary
         protection.  And, like paints, proper surface preparation
         and application are vital to long lasting protection.

    E.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing
         this procedure and should be followed, when applicable,
         along with recommendations from the Regional Historic
         Preservation Officer (RHPO).

1.02 DEFINITIONS

    A.   Semi-transparent Penetrating Stains:  Thin, moderately
         pigmented water repellents and water repellent
         preservatives which penetrate the wood allowing the
         natural grain and texture to show through.  

         1.   The addition of the pigment protects the wood
              against ultraviolet degradation and increases the
              durability of the finish.

         2.   Semi-transparent penetrating stains made from water
              repellent preservatives (WRP's) are recommended:

              a.   They provide additional protection against
                   decay.

              b.   They penetrate the wood rather than forming a
                   film they will not peel, flake or blister.

    B.   Solid Color (Opaque) Stains:  Provide an opaque finish
         with a slightly lower concentration of pigment than
         regular paints.  They result in a flat finish which hides
         the natural color and grain of the wood but maintain the
         original texture.  Available in both an oil-based or
         latex-based product, solid color stains form a thin film
         on the surface of the wood and are therefore subject to
         peeling, flaking, etc., just as paint is.  

1.03 DELIVERY, STORAGE AND HANDLING

    A.   Storage and Protection:  Stains shall be in sealed
         containers that legibly show the designated name, formula
         or specification number, batch number, color, quantity,
         date of manufacture, manufacturer's formulation number,
         manufacturer's directions including any warnings and
         special precautions and name of manufacturer.  Stains
         shall be stored on the project site and shall be stored
         to prevent freezing.  They shall be kept covered and
         safeguards taken to prevent fire.

 

1.04 PROJECT/SITE CONDITIONS

 

    A.   Environmental Requirements:

         1.   Unless otherwise recommended by the manufacturer, the ambient temperature shall be between 50 degrees F. and 95 degrees F. when applying either a stain or WRP.

         2.   Do not apply when the relative humidity exceeds 85% or the moisture content of the wood exceeds 12% as measured by an electronic moisture meter.

         3.   Do not apply a stain in the direct sun.  They shall be applied only when the surface to be treated is in the shade and the sun is shining on the opposite             elevation.  The west elevation should be treated in the morning when the sun is shining on the east elevation; the north elevation should be treated around noon when the sun is shining on the south elevation; the east elevation should be treated in the afternoon when the sun is shining on the west elevation; and the south elevation should be treated late in the afternoon when it is in full shade.

         4.   Do not apply stains to damp surfaces, in misty or rainy weather, in the snow or where there is visible ice or frost on the surfaces.

         5.   For optimal results when using a latex stain do not apply when the temperature is expected to go below 50 degrees F. within 24 hours of application.  On hot, dry days, to prevent the stain from drying too quickly, the surface can be slight ly dampened before the application of a latex stain.  Be sure to follow all manufacturer's instructions.




1.05 MAINTENANCE

    A.   Semi-transparent Penetrating Oil-based Stains Finish:

         1.   The life expectancy of these stains varies
              tremendously depending on whether one coat or two
              coats of stain were applied initially.  

              a.   A single coat, applied to smooth wood should
                   last 2 to 4 years.  

              b.   A two coat system, however, should last up to
                   8 years depending on the exposure.  Coastal
                   exposures or cold environments especially at
                   high altitudes will deteriorate more quickly,
                   as will most southern exposures.  A loss of
                   color is a good indication that the finish
                   must be renewed.

         2.   Clean surfaces with a stiff, nonferrous bristle
              brush to remove dirt and loose wood fibers.  

         3.   If the surface has mildewed, wash with bleach and
              detergent, rinse and let dry completely before
              applying a new coat of stain.  

         NOTE:  Because of the more porous nature of weathered
         wood and the better penetration of stain that results,
         subsequent applications will last somewhat longer than
         the initial application.

 

PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Benjamin Moore                    www.benjaminmoore.com

    B.   Flood Company                     www.flood.com

    C.   Minwax Co., Inc.      www.minwax.com

    D.   Olympic Stain                        www.olympic.com

    E.   PPG Pittsburgh Paints         www.ppgpittsburghpaints.com

    F.   Samuel Cabot, Inc.               www.cabotstain.com

    G.   Sherwin-Williams Co.          www.sherwin-williams.com

2.02 MATERIALS

    A.   General:

         1.   All stains shall be from the same manufacturer to avoid problems with penetration and coverage. Different batches of stain, even from the same manufacturer, should also be avoided for the same reasons. 

    B.   Oil modified alkyd semi-transparent penetrating stain such as "S-T Wood Preservative Stain, A14T5" (Sherwin Williams), or approved equal.  Other manufacturers are listed in Section 2.01 above.

         1.   Oil/alkyd based semi-transparent penetrating stains, which contain a wood preservative, are recommended over latex-based products.  Latex-based stains do not penetrate the surface and are subject to peeling, flaking, etc.

         2.   These stains are most effective on rough lumber and plywood, smooth lumber, weathered wood, and flat-grained surfaces of dense species that do not hold              paint well.

         3.   They can also be used over other penetrating finishes which have weathered to the point of needing to be renewed.

         4.   They are NOT, however, effective over paint, solid- color (opaque) stains or varnish, nor on smooth plywood.

    -OR-

            Solid color (opaque) stain such as "Series A14" (Sherwin  Williams), or approved equal.  Other manufacturers are listed in Section 2.01 above.

         1.   Though both oil- and acrylic-based solid colored stains are available, the acrylic-based stains are considered by the USDA's Forest Products Laboratory              to be the best of the opaque stains and are recommended here.

         2.   If the choice has been made to use an opaque stain, their use is recommended when going from a semitransparent penetrating stain or an opaque oil              stain to a lighter color, to cover a previously creosoted surface, or when covering new, close- pored wood species such as Southern yellow pine.  Like latex paint, acrylic -based opaque stains are also more resistant to mildew, are easy to apply and clean-up with soap and water.

         3.   Oil-base opaque stains may be successfully used on fresh, clean wood but they are NOT recommended for previously painted wood, even if all of the paint              has been removed.  Nor are they recommended for reapplication over existing oil-based opaque stains.  In both cases an uneven, splotchy appearance can be the result.

         4.   Solid color stains, either oil- or latex-based, are NOT recommended for flat, horizontal surfaces such as window sills, handrail s, porch floors, or decks.

       C.   Caulking compound:






         1.   Polyurethanes - easily workable; paintable; 15-20
              year life span; limited availability, see section
              on products and suppliers.

         2.   Polysulfides - slow drying; can be sanded and
              painted; highly elastic; limited availability, see
              section on products and suppliers.

         3.   Butyls - paintable but cannot be sanded; 7-10 year
              life span.

         4.   Silicones - some can be painted but generally not
              sanded.

         5.   Acrylic Latex - for exterior work, their use is
              best left to tight, narrow joints; short life span
              especially when compared to polysulfides and
              polyurethanes.

2.03 EQUIPMENT

    A.   Brushes:

         1.   Use natural bristle paint brushes for oil/alkyd
              stains.  Precondition by soaking in raw linseed oil
              for 24 hours.  Use nylon bristle brushes for latex
              stains.  Do not use the same brush for both types
              of stain.

         2.   For thin, runny stains, foam pad applicators can be
              used.

         3.   Stiff natural bristle scrub brushes.


PART 3---EXECUTION

3.01 PREPARATION

    A.   Surface Preparation:  Like any paint system, the surface
         to be treated must be clean and free of any loose, rough
         wood fibers, loose paint or varnish , or any mildew,
         grease or dust.  The surface must be as meticulously
         prepared for a stain as it would be if it were being
         painted.  See 06300-02-R for guidance on preparing wood
         surfaces for recoating.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   Mixing the Stain:

         1.   Mix the stain thoroughly and frequently.  This is
              important in maintaining an even color coverage.  

         2.   Pour off the top oils to a smaller container.  Stir
              the remaining contents until well mixed, add back
              the top oils and mix thoroughly again.  If
              possible, do all of the mixing in a larger
              container, i.e. use a five gallon paint to mix 2-3
              gallons of stain.  This will allow more vigorous
              and thorough mixing without fear of spilling.

         3.   When the first batch of stain is about 2/3 gone,
              stir the remaining stain into a new batch of stain.
              This will help even out any differences in color
              and pigment concentrations between cans.

         4.   Throughout the application stir the stain often to
              keep the pigments and oils well mixed.

    B.   Applying a semi-transparent (oil-based) penetrating
         stain:

         NOTE:  The application of a semi-transparent penetrating
         stain is best performed with a brush as it provides the
         best control.  Stains may also be spray- or roll-applied;
         however, an even application is difficult to achieve
         using either of these methods.  For stains that are
         especially thin, foam applicators will help control the
         application.

         1.   For dense species of wood such as Douglas Fir or
              Southern pine, treat the surfaces first with a
              water repellant preservative and let the wood
              weather for a year before staining.  See 06310-01-P
              for guidance.  This will allow the first coat of
              stain to penetrate more deeply and uniformly
              because the surface is more porous and will result
              in a more durable finish.

         2.   Start at the top of the area to be stained and work
              down, applying the stain to a small number of
              boards or a single panel at a time.  This will help
              avoid lap marks.  If possible, stop at a logical
              breaking point such as the end of an individual
              clapboard or at a door or window.  

              NOTE:  DO NOT LET THE FRONT EDGE DRY BEFORE
              BEGINNING THE NEXT SECTION.

              a.   When using a commercially available stain,
                   follow all manufacturer's instructions.

              b.   When using semi-transparent oil-based
                   penetrating stains, one gallon will cover
                   approximately 200-400 SF when applied to a
                   smooth surface, and 100-200 SF when applied to
                   a rough or weathered surface.

         3.   For rough or weathered surfaces, apply two (2)
              successive coats of the stain.  

              a.   Brush on the first coat of stain, again
                   working in small, logical areas.  Allow each
                   coat to soak into the wood for 20 to 60
                   minutes before applying the second coat, but
                   do not allow the first to dry completely.  

              b.   About an hour after the application of the
                   second coat of stain wipe off any excess stain
                   with a cloth, sponge, or brush which has been
                   sligh= tly dampened with the stain.

         4.   When used to cover an old, weathered penetrating
              natural finish:

              a.   Brush with a stiff bristle brush to remove
                   dust and loose wood fibers.  

                   NOTE:  DO NOT USE FERROUS BRUSHES OR WOOLS.
                   THESE CAN LEAVE SMALL IRON PARTICLES ON THE
                   SURFA CE OF THE WOOD.  CERTAIN WATER-SOLUBLE
                   EXTRACTIVES NATURALLY FOUND IN SOME WOODS SUCH
                   AS WESTERN RED CEDAR, REDWOOD, DOUGLAS-FIR AND
                   OAK CAN REACT WITH THE IRON PARTICLES CAUSING
                   BLUE-BLACK STAINING.  

                   PENTACHLOROPHENOL, A COMMON WOOD PRESERVATIVE
                   OFTEN FOUND IN SOME WRP'S AND SEMI-TRANSPARENT
                   PENETRATING STAINS, CAN ALSO CAUSE LOOSE IRON
                   PARTICLES TO CORRODE WHICH CAN IN TURN REACT
                   WITH THESE SAME WATER-SOLUBLE EXTRACTIVES
                   CAUSI= NG THE SAME BLUE-BLACK STAINING.

              b.   After applying the new coat of stain carefully
                   examine the surface.  

                   1)   A dull, flat surface will indicate that
                        the stain has evenly penetrated the wood.
                       
                   2)   A slightly glossy surface will indicate
                        that penetration of the stain was uneven
                        resulting in a less durable surface which
                        will need to be renewed more often.

         5.   During application, if it is possible, remove any
              trim pieces which are to be stained a different
              color because it is difficult to cut-in stain.  For
              better control and more even coverage and
              penetration, prestain any new wood.

    C.   Applying a solid color (opaque) stain:

         NOTE:  Opaque stains react much the same way as do oil-
         based and latex paints.  Brush application is the best
         but a roller may also be used.  Follow the same
         procedures outlined for semi-transparent penetrating
         stains in Section 3.02 B. above.

3.03 ADJUSTING/CLEANING

    A.   As with quality surface preparation for painted surfaces,
         caulking joints is an important part of surface
         preparation.  CAULKS, however, ARE NOT STAINABLE, so
         caulk after staining has been complete.  Also caulk after
         a WR or WRP has been applied.

                         END OF SECTION

 


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