Historic Preservation - Technical Procedures
Epoxy Patching Cracks In Limestone
Nationa Capitol Region Specifications - Mad/Cosmos/Tayloe
Epoxy Patching Cracks In Limestone
EPOXY PATCHING CRACKS IN LIMESTONE
A. This procedure includes guidance on patching cracks in
limestone using an epoxy resin. This type of repair is
suited for dormant (inactive) cracks no larger than 3/8"
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).
1.02 QUALITY ASSURANCE
A. Contractor: A skilled firm with not less than ten (5)
years experience in masonry repointing and restoration.
The Contractor shall be required to submit references for
five (5) successfully completed projects of similar
B. Source of Material: Obtain materials for stone
restoration from a single source for each type of
material required, to ensure match of quality, color,
pattern, and texture.
1.03 PROJECT/SITE CONDITIONS
A. Environmental Requirements: Perform work only in dry and
otherwise favorable weather conditions. Protect repaired
masonry against freezing or excessively rapid drying for
at least 48 hours after being laid. Do not repoint mortar
joints or repair masonry unless air temperatures are
between 40 F (4 C) and 80 F (27 C) and will remain so for
at least 48 hours after completion of work.
A. Akemi Plastic, Inc.
Eaton Rapids, MI
B. Euclid Chemical Company
C. E-Poxy Industries, Inc.
A. Epoxy-Based Stone Repair Adhesive: A commercially
available, two component, moisture insensitive, high
modulus, low viscosity, epoxy resin-formulated for
penetrating deep into thin masonry cracks, such as
"Akepox" (Akemi Plastic, Inc.), "Eucopoxy Injection
Resin" (Euclid Chemical Company), "Eva-Pox Injection
Resin #4" (E-Poxy Industries, Inc.), or approved equal.
B. Single Source Responsibility: Provide epoxy resin,
hardener and solvent produced by the same manufacturer.
C. Acetone (C3H6O):
1. A volatile fragrant flammable liquid ketone used
chiefly as a solvent and in organic synthesis.
2. Other chemical or common names include Dimethyl
3. Potential Hazards: VOLATILE AND FLAMMABLE SOLVENT
4. Available from chemical supply house or hardware
D. Limestone Dust
E. Clean, potable water
B. Stiff bristle brushes (non-metallic)
1. Take whatever precautions are necessary to protect
the existing building from damage resulting from
work under this section.
2. Prevent mortar and patching compounds used in
repointing and repair work from staining face of
surrounding masonry and other surfaces. Remove
immediately mortar and patching compounds in
contact with exposed masonry and other surfaces.
3. Improper use of chemicals may constitute a health
hazard. Refer to manufacturer's Material Safety
Data Sheets for hazard data, special protection for
use and precautions to be taken in handling and
storage. Comply with manufacturer's recommendations
for proper use of chemicals.
3.02 ERECTION, INSTALLATION, APPLICATION
A. Thoroughly clean dust, dirt and debris from crack.
B. Wipe surfaces to be bonded with acetone and allow to dry
C. Thoroughly and completely mix resin and hardener (2
minutes). Mix at low speeds to minimize entrapped air.
Blend the epoxy adhesive to match color matrix of
adjacent limestone by adding color limestone dust or
D. Mask stone surfaces adjacent to crack to prevent staining
of the limestone during repair operation.
E. After mixing, inject epoxy into cracks with a syringe and
allow to seep in. Continue to apply material until crack
is full. Sprinkle limestone dust on epoxy adhesive to
F. Clean tools and any tape residue with acetone or solvent
specifically formulated for the particular product used.
END OF SECTION