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Historic Preservation - Technical Procedures

Spectitle:
Removing Paint From Wood Features Using Thermal Methods

Procedure code:
0640009R

Source:
Hspg Prepared For Nps - Sero

Division:
Wood And Plastics

Section:
Architectural Woodwork

Last Modified:
02/24/2012

Details:
Removing Paint From Wood Features Using Thermal Methods



REMOVING PAINT FROM WOOD FEATURES USING THERMAL METHODS


BEFORE UNDERTAKING ANY PROJECT INVOLVING PAINT REMOVAL, APPLICABLE
STATE AND FEDERAL LAWS ON LEAD PAINT ABATEMENT AND DISPOSAL MUST
BE
TAKEN INTO ACCOUNT AND CAREFULLY FOLLOWED.  STATE AND FEDERAL
REQUIREMENTS MAY AFFECT OPTIONS AVAILABLE TO OWNERS ON BOTH PAINT
REMOVAL AND REPAINTING.  THESE LAWS, AS WELL AS ANY REQUIREMENTS
PROHIBITING VOLATILE ORGANIC COMPOUNDS (VOCs), SHOULD BE REQUESTED
FROM THE STATE HISTORIC PRESERVATION OFFICER IN EACH STATE.  (From
Preservation Brief 28, "Painting Historic Interiors").  REGULATORY
INFORMATION MAY ALSO BE REQUESTED FROM THE ENVIRONMENTAL
PROTECTION
AGENCY (EPA) REGIONAL OFFICE AND/OR THE STATE OFFICE OF
ENVIRONMENTAL QUALITY.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing paint from
         interior and exterior wood features using thermal methods.

    B.   In general, heat should not be used on windows.  If,
         however, a thermal method is used, the glass should be
         removed to a safe storage place to be reinstalled, or
         protected from the sudden temperature change which can
         cause breakage.  An overlay of aluminum foil on gypsum
         board or asbestos can protect the glass from such rapid
         temperature change.  

    C.   Safety Precautions:

         1.   Use appropriate safety precautions such as gloves,
              goggles and respirators.  Old paint layers will
              likely contain lead.  Avoid breathing paint dust
              during removal.

         2.   No food or drink shall be allowed near any work
              station so as to prevent contamination from paint,
              paint chips or dust which contain lead and other
              toxic substances.

         3.   Protective clothing shall be removed at the end of
              each day and kept at the site to prevent workers
              from tracking dust and paint chips to other parts
              of the site or to their homes.

         4.   Wash hands and face often, especially before eating
              and at the end of the day.

    D.   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).

    E.   See also 06400-02-S for supplemental information on
         removing paint from wood features.

    F.   For additional information on the history and properties
         of paint along with general procedures for paint removal,
         see 09900-01-S, "Preservation Brief 28, Painting Historic
         Interiors", and 09910-01-S, "Preservation Brief 10,
         Exterior Paint Problems on Historic Woodwork".

1.02 REFERENCES

    A.   AWI Quality Standard:  Comply with applicable
         requirements of "Architectural Woodwork Quality
         Standards" published by the Architectural Woodwork
         Institute (AWI), except as otherwise indicated.

1.03 DEFINITIONS

    A.   Thermal Methods:  as used herein shall apply to either of
         the two approved (by the Secretary of the Interior)
         methods of paint removal using heat.  This includes the
         heat plate and the heat gun.  

    B.   BLOW TORCHES ARE NOT RECOMMENDED BY THE SECRETARY OF THE
         INTERIOR'S STANDARDS FOR REHABILITATION PROJECTS AND
         SHOULD NOT BE USED.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   For Heat Plate:

         1.   Hyde Manufacturing
              54 Eastford Road
              Southbridge, MA  01550
              508/764-4344

         2.   The Old House Journal
              2 Main Street
              Gloucester, MA  01930
              508/281-8803

    B.   For Heat Gun:

         1.   Master Appliance Corporation
              2420 18th Street
              Racine, WI  53403
              414/633-7791

         2.   The Old House Journal
              2 Main Street
              Gloucester, MA  01930
              508/281-8803

2.02 EQUIPMENT

    A.   Electric Heat Plate such as "Hydelectric Heat Plate"
         (Hyde Tools), the "Warner Heat Plate", or approved equal.

         1.   Operating temperature between 500o F. and 800o F.  

         2.   Works by means of a red hot coil, much like a
              burner on an electric stove at operating
              temperatures high enough to soften the paint layers
              without vaporizing the lead in any lead paint
              layers.

    B.   Electric Heat Gun such as Master's Model Number 499,
         Master's HG-501 (Master Appliance Corporation) or
         approved equal.

         1.   Heavy duty heat gun with metal case.

         2.   Operating temperature between 500o and 750o F.

         3.   The heat gun heats a much smaller area at a time
              than does the heat plate.  The danger in using a
              heat gun is that the hot air blast can ignite dust,
              birds' nests, or other debris within a wall cavity
              or behind a cornice or soffit.  The dust can
              smolder only to ignite hours later after the work
              crew has gone home so extreme caution must be taken
              when using this method.

    C.   A number of replacement heat elements for heat gun should
         also be kept on hand.  

    D.   Power Supply:  Both devices draw approximately 15 amps of
         power.  Each work station is to be provided with its own
         temporary power supply so as not to overload other
         circuits

    E.   A variety of putty knives and paint scrappers of
         different shapes and flexibility.  Corners should be
         ground to a rounded shape to prevent gouging the wood
         surfaces.  A glazers 5-in-1 tool also works well.

    F.   Extension Cords:  Proper, heavy-duty extension cords are
         required


PART 3---EXECUTION

3.01 EXAMINATION

    A.   One of the main reasons for paint failure is excess
         moisture, both from internal and external sources.
         Before work is begun on removing the existing paint film
         or otherwise preparing the surface, all flashing and
         gutters and downspouts shall be inspected and repaired or
         replaced as required.  Make provisions as required for
         removing excess moisture from areas of high humidity.  

    B.   All wood elements shall be carefully inspected for rot
         and, if deteriorated, marked for later replacement, after
         the paint has been removed.

    C.   If accessible, check cavities behind cornices, soffits,
         etc. for bird's nests and other debris.

3.02 PREPARATION

    A.   Protection:

         1.   Protect adjacent surfaces, including grass, shrubs
              and trees with paper, drop cloths and other means.
             
         2.   Items not painted which are in contact with or
              adjacent to painted surfaces shall be removed or
              protected prior to surface preparation and painting
              operations.

         3.   All waste material shall be collected at the end of
              each work day and disposed of in a manner
              consistent with local environmental regulations.
              It is considered Hazardous Waste.

         4.   Work area shall be sealed to prevent the spread of
              paint dust and debris beyond the work site.

         5.   After paint removal is complete, all areas around
              the site shall be cleaned of all paint dust and
              debris, and such debris shall be properly disposed
              of in a manner consistent with local environmental
              regulations.  Vacuums used to clean up dust shall
              be equipped with High Efficiency Particulate Air
              (HEPA) filters.

         6.   When using either thermal method, keep a fire
              extinguisher handy.  Work should also be stopped
              several hours before the day's work is completed
              and the job site is vacated so that smoldering
              fires can be detected.

3.03 ERECTION, INSTALLATION, APPLICATION

    A.   Place thermal device (heat gun or heat plate) over area
         to be stripped and heat paint until it begins to soften
         and wrinkle.  Do not let paint bubble--at this high
         temperature the wood may become scorched.

         1.   Use the heat plate on broad, flat surfaces such as
              clapboards, doors and window sills.

              CAUTION:  NEVER PLACE THE HEAT PLATE DIRECTLY ON
              THE SURFACE.  THE HEAT OF THE PLATE MAY IGNITE THE
              PAINT OR SCORCH THE WOOD.

         2.   Use a heat gun on smaller, narrow or curved
              surfaces, on more intricate details or moldings, or
              solid wooden elements.  Small parts of window sash
              such as the sash runs, stops, parting bead, etc.
              can also be successfully stripped using a heat gun.

    B.   Using a scraper whose corners have been rounded, scrape
         and remove paint.  With practice, the heat plate or gun
         and the scrapper can be moved at the same time so that
         the paint comes off quickly, in long ribbons.

    C.   To remove last traces of paint it may be necessary to go
         over surfaces with a liquid paint remover, see 06400-07-R.

    D.   For guidance on repainting wood features, see 06300-01-S,
         06300-02-R and 09900-07-S.  For guidance on refinishing
         wood with a varnish or stain, see 06400-10-R.

3.04 ADJUSTING/CLEANING

    A.   Upon completion of this work, all floors, walls and other
         adjacent surfaces that are stained, marred, otherwise
         damaged by work shall be cleaned and repaired and all
         work and the adjacent areas shall be left in a clean and
         orderly condition.

    B.   All completed work shall be adequately protected from
         damage by subsequent building operations and effects of
         weather.  Protection shall be by methods recommended by
         the manufacturer of installed materials and as approved
         by the Architect.

                         END OF SECTION