Historic Preservation - Technical Procedures
- Replacing Deteriorated Caulk At Masonry Surfaces
- Procedure code:
- National Capitol Region Specifications - Old Executive Off
- Thermal And Moisture Protection
- Joint Sealers
- Last Modified:
- Replacing Deteriorated Caulk At Masonry Surfaces
- Last Modified:
REPLACING DETERIORATED CAULK AT MASONRY SURFACES
A. This procedure includes guidance on caulking all joints
on horizontal or sloping existing masonry surfaces
including, but not limited to: cornices, parapets, window
sills, platforms steps and other wash 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).
A. The following publications of the issues listed below,
but referred to thereafter by basic designation only,
form a part of this specification to the extent indicated
by references thereto:
1. TT-S-001543A Sealing Compound, Silicone Rubber
Base (for (COMM-NBS) Caulking, Sealing and Glazing in
Buildings and Other Structures).
2. UU-T-00106D Tape, Pressure-Sensitive Adhesive, Masking,
1.03 SYSTEM DESCRIPTION
A. General: Caulking or sealant shall be provided in joints
as indicated or specified. Materials shall conform to the
respective specifications and other requirements
specified. The work specified herein shall be performed
by workers skilled in such work.
B. Sealant Formulation Intended Application: Each container
brought to the jobsite shall be marked for the intended
use. The color shall be one of the manufacturer's
standard colors as closely matching the adjacent surfaces
as possible. The sealant formulation shall conform to the
requirements specified herein.
C. Thinners or other additives shall not be used to modify
1. Materials: Prior to delivery of the caulking and
sealant to the jobsite, a one-cartridge or
equivalent representative sample of the caulking
and sealant specified herein shall be furnished.
The sample shall be accompanied by certified
laboratory test reports showing that the caulking
and sealant to be furnished have been tested within
the last 12 months and meet the requirements of the
applicable specifications. The sample container
shall include the same information on the label as
specified herein for containers delivered to the
2. Joints: Before work is started, a sample of each
type of joint shall be caulked or sealed where
directed. The samples shall show the materials,
workmanship bond, and color of materials as
specified or selected for the work. The materials,
workmanship, bond, and color throughout the project
shall match that of the approved sample joint.
1.05 DELIVERY, STORAGE AND HANDLING
A. Packing and Shipping: Materials shall be delivered to
the job in the manufacturers' original unopened
containers. The containers shall include the following
information on the label: supplier, name of material,
formula or specification number, lot number, color, date
of manufacture, mixing instructions, shelf life, and
curing time when applicable at the standard conditions
for laboratory tests. All materials shall be carefully
handled and stored to prevent inclusion of foreign
materials, or components outdated as indicated by shelf
life shall not be used.
1.06 PROJECT/SITE CONDITIONS
A. Environmental Requirements: The ambient temperature shall
be within the limits of 40 and 90 F when the caulking
and sealants are applied.
A. Sealant shall be a cone-component, elastomeric-type
compound conforming to TT-S-1543, class A. The compound
shall be supplied in a ready-to-use form which requires
no on-the-job mixing.
B. Backup material shall be closed-cell polyethylene foam.
Backup material shall be nonabsorbent, nonstaining, and
compatible with the sealant used. Tube or rod stock when
used shall be rolled into the joint cavity.
C. Bond-preventive materials shall be one of the following,
as recommended by the sealant manufacturer.
D. Polyethylene Tape, Pressure-sensitive Adhesive: The
adhesive is required only to hold tape to the
construction materials as indicated.
E. Masking tape shall conform to UU-T-106.
A. Surface Preparation:
1. The joint design, shape, and spacing shall be as
indicated by the RHPO. The surfaces of joints to be
sealed shall be dry. Oil, grease, dirt, chalk,
particles or mortar, dust, loose rust, loose mill
scale, and other foreign substances shall be
removed form all joint surfaces to be sealed. Oil
or grease shall be removed with solvent and
surfaces shall be wiped with clean cloths.
2. Concrete and Masonry Surfaces: Where surfaces have
been treated with curing compounds, oil, or other
such materials they shall be removed by wire
brushing. Laitance, efflorescence and loose mortar
shall be removed from the joint cavity.
3. Steel surfaces to be in contact with sealant shall
be scraped and wire brushed to remove loose mill
scale. Protective coatings on steel surfaces shall
be removed by a solvent that leaves no residue.
3.02 ERECTION, INSTALLATION, APPLICATION
A. Joint Types and Sealants: Unless otherwise specified, for
all joints requiring sealant on horizontal or sloping
surfaces. The joint shapes and sizes shall be indicated
below unless otherwise specified:
Sealant (No.) (Type) Sealant Form
TT-S-001543A Type II Ready to Use
B. Paper masking tape shall be placed on the finish surface
on one or both sides of a joint cavity to protect
adjacent finish surfaces from primer or compound smears.
Masking tape shall be removed within ten minutes after
joint has been filled and tooled.
C. Bond-preventive materials for rubber-base sealant shall
be installed on the bottom of the joint cavity and other
surfaces indicated to prevent the sealant from adhering
to the surfaces covered by the bond-preventive materials.
The materials shall be carefully applied to avoid
contamination of adjoining surfaces or breaking bond with
surfaces other than those covered by the bond-
preventative materials. At the option of the Contractor,
backstop material with bond-breaking characteristics may
be installed in lieu of bond-preventive materials
D. Backstops: The back or bottom of joints constructed
deeper than indicated shall be packed tightly with
backstop material to provide a joint of depth indicated.
E. Elastomeric Type Sealant: Compound shall be gun-applied
with a nozzle of proper size to fit the width of joint
indicated and shall be forced into grooves with
sufficient pressure to expel air and fill the groove
solidly. Sealant shall be uniformly smooth and free of
wrinkles. Joints shall be tooled slightly concave after
sealant is installed. When tooling white or light-color
sealant, dry or water-wet tool shall be used.
A. The surfaces adjoining the caulked and sealed joints
shall be cleaned of smears and other soiling resulting
from the caulking and sealing application as work
END OF SECTION