Regrouting Deteriorated Joints In Marble
- Procedure code:
- Tacoma Union Station Courthouse/Tacoma, Wa - Gsa/Pbs
- Last Modified:
REPOINTING DETERIORATED JOINTS IN MARBLE
A. This procedure includes guidance on repointing
deteriorated joints in marble.
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).
A. American Society for Testing and Materials (ASTM)
B. American National Standard Institute (ANSI)
www.ansi.org (use most reecent versions).
A. Setting Materials: Joints should be filled to match
existing mortar or marble color, as directed by Regional
Historic Preservation Officer (RHPO).
1. Portland Cement: ANSI/ASTM C 150, Type I, except
complying with staining requirements of ASTM C 91
for not more than 0.03% water soluble alkali
2. Hydrated Lime: ANSI/ASTM C 207, Type I
3. Sand: ANSI/ASTM C 144, non-staining, except graded
with 100% passing the No. 166 sieve for 1/4" and
a. For white pointing mortar and grout, furnish
natural white sand or ground white stone
complying with specified requirements
b. For colored pointing mortar and grout, furnish
ground marble, granite or other sound stone,
meeting specified grading requirements for
sand, of color required to match existing
mortar and grout color
4. Clean, potable water
5. Dry-Set Mortar: Factory-sanded Portland cement and
additives complying with ANSI A 118.1, of type
approved by mortar manufacturer and marble supplier
for application indicated
B. Molding Plaster: ANSI/ASTM C 59
C. Clean, potable water
A. Masonry Drill
B. Hacksaw Blade
C. Chisel and mallet for removing deteriorated grout
D. Brushes: Soft bristled nylon only
E. Hand-held Water Bottle
F. Steel Trowel
A. Protection: Prevent mortar used in repointing
and repair work from staining face of surrounding marble
and other surfaces. Remove immediately mortar
in contact with exposed marble and other surfaces.
3.02 ERECTION, INSTALLATION, APPLICATION
A. Carefully remove deteriorated mortar from
joints by hand with a chisel and mallet and other hand
tools, unless otherwise indicated and approved by RHPO.
B. Clean marble surfaces within raked-out joints to provide
reveals with square backs and to expose marble for
contact with pointing mortar. Brush, vacuum or flush
joints to remove dirt and loose debris.
CAUTION: BE CAREFUL NOT TO SPALL EDGES OF MARBLE UNITS.
EPOXY PATCH ANY EXISTING MARBLE UNITS WHICH BECOME
DAMAGED. SEE 04455-03-R FOR EPOXY PATCHING PROCEDURES.
C. Fill joints in marble unit with new mortar of color to match
existing mortar color or to match marble color as directed, except at
expansion and control joints indicated to be filled with
sealant. Color of mortar shall be established in mock-ups.
Finish mortar flush with finished surface of marble, or replicate the original pointing style of mortar.
D. Fill all gaps and skips to produce a finished joint which
is uniform in color, smooth and without voids, pinholes,
or low spots.
E. Remove mortar spillage from face of marble as work
F. Cure mortar by maintaining in a moist condition for 7
G. For Regrouting Stone Floors: Do not permit traffic
during setting of units or for at least 24 hours after
final grouting of joints.
END OF SECTION