Patching Small Chips And Cracks In Plaster
- Procedure code:
- Tacoma Union Station Courthouse/Tacoma, Wa - Gsa/Pbs
- Gypsum Plaster
- Last Modified:
PATCHING SMALL CHIPS AND CRACKS IN PLASTER
A. This procedure includes guidance on patching small chips,
cracks or depressions in plaster surfaces.
B. 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
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).
C. For guidance on repairing hairline cracks, see 09210-02-
R; for guidance on repairing large holes, see 09200-12-R
A. American National Standards Institute (ANSI)
B. American Society for Testing and Materials (ASTM)
A. USG Corporation
A. Gypsum Plaster Materials:
1. General: gypsum plastering materials shall conform
to ANSI A42.1. Provide neat or ready-mixed
materials at installer's option unless indicated
2. Base coat plaster: Perlite gypsum plaster such as
"Structo-Lite" (USG Corp.), or
3. Base coat aggregate: Sand.
4. Finish coat plaster: Keene's cement.
5. Finishing lime: Type is installer's option.
B. Bonding Materials: Bonding agent shall conform to ASTM
A. Joint knife
B. Sponge or heavy-nap cloth
C. Crack widener or triangular can opener
D. Stiff bristle brushes
F. Slicker (flexible straight-edge)
G. Plasterer's trowel
H. Margin trowel
I. Mortarboard and mudpan
J. Pointing trowel
3.01 ERECTION, INSTALLATION, APPLICATION
A. Scrape loose or damaged finish plaster and peeling paint
from surface with chisel or joint knife. Remove material
where required to enlarge cracks, chips, holes, etc. to
at least 1/2 inch across and undercut to improve bonding
of new material.
B. Brush or vacuum surface to remove dust and debris.
C. Moisten the surface by lightly spraying a fine mist of
clean water from a spray bottle.
D. Apply skim finish coat over low areas to bring entire
finished surface out flush with the projecting firm and
sound layers of adjacent plaster or paint. Form plaster
as required to match original configuration and design or
E. Once dry, sand by hand to produce a surface without
bumps, cracks or depressions, ready to receive finish
A. Upon completion of this work, all floors, walls and other
adjacent surfaces that are stained, marred, or otherwise
damaged by work in this procedure shall be cleaned and
repaired and all work and the adjacent areas shall be
left in a clean and perfect 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 RHPO.
END OF SECTION