Historic Preservation - Technical Procedures
Sealing Masonry Joints To Make Them Airtight And Watertight
Fed Bldg/Uspo/Spokane, Wa - Gsa/Pbs, 3-11-91
Thermal And Moisture Protection
Sealing Masonry Joints To Make Them Airtight And Watertight
SEALING MASONRY JOINTS TO MAKE THEM AIRTIGHT AND WATERTIGHT
THE USE OF CAULKS AND SEALANTS IN THE MASONRY JOINTS OF HISTORIC
STRUCTURES, IS ONLY AN APPROPRIATE MAINTENANCE TREATMENT WHEN IT IS
INTENDED TO REPLACE CAULKING OR SEALANTS USED AS PART OF THE
ORIGINAL DESIGN. THIS WORK SHOULD BE PERFORMED BY AN EXPERIENCED
A. This procedure includes guidance on installing joint
sealers at masonry joints for the following locations:
1. Exterior joints in vertical surfaces and non-
traffic horizontal surfaces; these may include
perimeter joints at frames of doors and windows.
2. Exterior joints in horizontal traffic surfaces;
these may include joints in stone steps (see also
3. Interior joints in vertical surfaces and horizontal
non-traffic surfaces; these may include perimeter
joints between interior wall surfaces and frames of
interior doors, windows and elevator entrances, or
perimeter joints of toilet fixtures.
4. Interior joints in horizontal traffic surfaces;
these may include joints in stone steps.
B. For guidance on selecting joint sealants for masonry,
based on composition, elasticity and durability, see
07900-01-S "Criteria For Selecting Masonry Joint
A. American Society for Testing and Materials (ASTM), 100
Barr Drive, West Conshohocken, PA 19428, (610) 832-9585
or FAX (610) 832-9555.
1.03 SYSTEM DESCRIPTION
A. Provide joint sealers that have been produced and
installed to establish and maintain watertight and
airtight continuous seals.
A. Product Data from manufacturer's for each joint sealer
product required, including instructions for joint
preparation and joint sealer application.
B. Samples of each type and color of joint sealer required.
Install joint sealer samples in 1/2" wide joints formed
between two 6" long strips of material matching the
appearance of exposed surfaces adjacent to joint sealers.
C. Certificates from manufacturers of joint sealers
attesting that their products comply with specification
requirements and are suitable for the use indicated.
1.05 QUALITY ASSURANCE
A. Installer Qualifications: Engage an Installer who has
successfully completed within the last 3 years at least
3 joint sealer applications similar in type and size to
that of this project.
B. Single Source Responsibility for Joint Sealer Materials:
Obtain joint sealer materials from a single manufacturer
for each different product required.
C. Preconstruction Field Testing: Prior to installation of
joint sealants, field-test their adhesion to joint
substrates as follows:
1. Conduct field tests for each application indicated
a. Each type of elastomeric sealant and joint
b. Each type of non-elastomeric sealant and joint
2. Arrange for tests to take place with both RHPO and
joint sealer manufacturer's technical
3. Test Method: Test joint sealers by hand pull
method described below:
a. Install joint sealants in 5-feet joint lengths
using same materials and methods required for
joint preparation and joint sealant
installation required for completed work.
Allow sealants to cure fully before testing.
b. Make knife cuts as follows: A horizontal cut
from one side of joint to the other followed
by 2 vertical cuts approximately 2" long at
side of joint and meeting horizontal cut at
top of 2" cuts. Place a mark 1" from top of
c. Use fingers to grasp 2" piece of sealant just
above 1" mark; pull firmly down at a 90 degree
angle or more while holding a ruler along side
of sealant. Pull sealant out of joint to the
distance recommended by sealant manufacturer
for testing adhesive compatibility, but not
less than that equaling specified maximum
movement capability in extension; hold this
position for 10 seconds.
4. Report whether or not sealant in joint connected to
pulled-out portion failed to adhere to joint
substrates or tore cohesively. Include data on
pull distance used to test each type of product and
5. Evaluation of Field Test Results: Sealants not
evidencing adhesive failure from testing, in
absence of other indications of noncompliance with
requirements, will be considered satisfactory. Do
not use sealants which fail to adhere to joint
substrates during testing.
D. Pre-Installation Meeting: At contractor's direction,
installer, joint sealer manufacturers' representatives,
and other trades whose work affects installation of joint
sealers shall meet at project site to review procedures
and time schedule proposed for installation of joint
sealers which is coordinated with other, related work.
1.06 DELIVERY, STORAGE AND HANDLING
A. Acceptance at Site: Deliver materials to project site in
original unopened containers or bundles with labels
informing about manufacturer, product name and
designation, color, expiration period for use, pot life,
curing time and mixing instructions for multi-component
B. Storage and Protection: Store and handle materials in
compliance with manufacturer's recommendations to prevent
their deterioration or damage due to moisture, high or
low temperatures, contaminants, or other causes.
1.07 PROJECT/SITE CONDITIONS
A. Environmental Conditions: Do not proceed with
installation of joint sealers under the following
1. When ambient and substrate temperature conditions
are outside the limits permitted by joint sealer
manufacturer or below 40 degrees F (4.4 degrees C).
2. When joint substrates are wet due to rain, frost,
condensation or other causes.
B. Joint Width Conditions: Do not proceed with installation
of joint sealers where joint widths are less than allowed
by joint sealer manufacturer for application indicated.
C. Joint Substrate Conditions: Do not proceed with
installation of joint sealers until contaminants capable
of interfering with their adhesion are removed for joint
1.08 SEQUENCING AND SCHEDULING
A. Sequence installation of joint sealers to occur not less
than 21 nor more than 30 days after completion of
waterproofing, unless otherwise indicated.
A. Bostik Construction Products
Middleton, MA 01949
800/726-7845, FAX 508/774-7376
B. Dow Corning Corporation
1225 Northmeadow Parkway, Ste. 104
Roswell, GA 30076
P.O. Box 994
Midland, MI 48686-0994
C. General Electric Co.
Silicone Products Division
Waterford, NY 12188
D. Mameco International, Inc.
4475 East 175th Street
Cleveland, OH 44128
E. Pecora Corporation
165 Wambold Road
Harleysville, PA 19438
800/522-1285 or 215/723-6051
2601 Oakland Avenue
Garland, TX 75041
800/523-6688 or 214/278-8158
F. Sika Corporation
201 Polito Ave.
Lyndhurst, NJ 07071
G. 3M Consumer Products Group
St. Paul, MN 55133-3053
612/737-6501 or 800/364-3577
H. Tremco, Inc.
3735 Green Rd.
Beachwood, OH 44122
A. For additional guidance on selecting masonry joint
sealants, see 07900-01-S "Criteria for Selecting Masonry
1. Compatibility: Provide joint sealers, joint
fillers and other related materials that are
compatible with one another and with joint
substrates under conditions of service and
application, as demonstrated by sealant
manufacturer based on testing and field experience.
2. Colors: Provide color of exposed joint sealer
indicated or, if not otherwise indicated, as
selected by Contracting Officer from manufacturer's
C. Elastomeric Joint Sealants:
1. Elastomeric Sealant Standard: Provide
manufacturer's standard chemically curing,
elastomeric sealant of base polymer indicated which
complies with ASTM C920 requirements, including
those referenced for Type, Grade, Class and Uses.
2. One-Part Mildew-Resistant Silicone Sealant such as
"Dow Corning 786" (Dow Corning Corporation), "SCS
1702" (General Electric Co.), or approved equal.
a. Type S; Grade NS; Class 25
b. Uses NT, G, A, and, as applicable to non-porous joint substrate indicated, O
c. Formulated with fungicide for sealing interior
joints with nonporous substrate around ceramic
tile, showers, sinks and plumbing fixtures.
3. One-Part Non-sag Urethane Sealant for Use NT such
as "Chem-Calk 900" or "Chem-Calk 2639" (Bostik
Construction Products), "Vulkem 116" or "Vulkem
921" (Mameco International, Inc.), "Sikaflex-1a" or
"Sikaflex-15LM" (Sika Corporation), or approved
a. Type S; Grade NS; Class 25
b. Uses NT, M, A, and, as applicable to joint
substrates indicated, O.
4. One-Part Non-sag Urethane Sealant for Use T such as
"Chem-Calk 900" (Bostik Construction Products),
"Sikaflex-1a" or "Sikaflex-15LM" (Sika
Corporation), or approved equal.
a. Type S; Grade P; Class 25.
b. Uses T, M, and, as applicable to joint
substrates indicated, O.
5. One-Part Pourable Urethane Sealant for Use T such
as "Chem-Calk 950" (Bostik Construction Products)
"Vulkem 45" (Mameco International, Inc.), or
D. Latex Joint Sealants:
1. Acrylic-Emulsion Sealant such as "Chem-Calk 600"
(Bostik Construction Products), or approved equal.
a. Manufacturer's standard, one part, non-sag,
acrylic, mildew-resistant, acrylic-emulsion
sealant complying with ASTM C834.
b. Formulated to be painted and recommended for
exposed applications on interior and on
protected exterior exposures involving joint
movement of not more than + or - 7.5%.
E. Acoustical Joint Sealants:
1. Acoustical Sealant for Concealed Joints such as
"BA098" (Pecora Corporation), "Tremco Acoustical
Sealant" (Tremco, Inc.), or approved equal.
a. Manufacturer's standard, non-drying, non-hardening, non-skinning, non-staining,
gunnable, synthetic rubber sealant.
b. Recommended for sealing interior concealed
joints to reduce transmission of airborne
F. Fire-Resistant Joint Sealers:
1. General: Provide manufacturer's standard fire-
stopping sealant, with accessory materials, having
fire-resistance ratings indicated as established by
testing identical assemblies per ASTM E814 by
Underwriters Laboratory, Inc. or other testing and
inspecting agency acceptable to authorities having
2. Foamed-In-Place Fire-Stopping Sealant such as "Dow
Corning Fire Stop Foam" (Dow Corning Corporation),
"Pensil 851" (General Electric Co.), or approved
a. Two-part, foamed-in-place, silicone sealant
formulated for use in a through-penetration
b. For filling openings around cables, conduit,
pipes and similar penetrations through walls
3. One-Part Fire-Stopping Sealant such as "Dow Corning
Fire Stop Sealant" (Dow Corning Corporation), "3M
Fire Barrier Caulk CP-25" (Electrical Products
Div./3M), "RTV 7403" (General Electric Co.), or
a. One-part elastomeric sealant formulated for
use in a through-penetration fire-stop system.
b. For sealing openings around cables, conduit,
pipes and similar penetrations through walls
G. Joint Sealant Backing:
1. General: Provide sealant backings of material and
type which are non-staining; are compatible with
joint substrates, sealants, primers and other joint
fillers; and are approved for applications
indicated by sealant manufacturer based on field
experience and laboratory testing.
2. Plastic Foam Joint Fillers: Preformed,
compressible, resilient, non-waxing, non-extruding
strips of flexible, non-gassing plastic foam of
material indicated below; non-absorbent to water
and gas; and of size, shape and density to control
sealant depth and otherwise contribute to producing
optimum sealant performance.
a. Either open cell polyurethane foam or closed-
cell polyethylene foam, unless otherwise
indicated, subject to approval of sealant
manufacturer, for cold-applied sealants only.
b. Elastomeric Tubing Joint-Fillers: Neoprene,
butyl or EPDM tubing complying with ASTM
D1056, non-absorbent to water and gas, capable
of remaining resilient at temperatures down to
-26 degrees F (-15 degrees C). Provide
products with low compression set and of size
and shape to provide a secondary seal, to
control sealant depth and otherwise contribute
to optimum sealant performance.
3. Bond-Breaker Tape: Polyethylene tape or other
plastic tape as recommended by sealant manufacturer
for preventing sealant from adhering to rigid,
inflexible joint filler materials or joint surfaces
at back of joint where such adhesion would result
in sealant failure. Provide self-adhesive tape
H. Miscellaneous Materials:
1. Primer: Provide type recommended by joint sealer
manufacturer where required for adhesion of sealant
to joint substrates indicated, as determined from
preconstruction joint sealer substrate tests and
2. Cleaners for Nonporous Surfaces: Provide non-
staining, chemical cleaners of type which are
acceptable to manufacturer of sealants and sealant
backing materials, which are not harmful to
substrates and adjacent non-porous materials, and
which do not leave oily residues or otherwise have
a detrimental effect on sealant adhesion or in-
3. Masking Tape: Provide non-staining, non-absorbent
type compatible with joint sealants and to surfaces
adjacent to joints.
4. Accessory materials for Fire-Stopping Sealants:
Provide forming, joint-fillers, packing and other
accessory materials required for installation of
fire-stopping sealants as applicable to
installation conditions indicated.
I. Joint Fillers for Concrete Paving:
1. General: Provide joint fillers of thickness and
2. Bituminous Fiber Joint Filler: Preformed strips of
composition below, complying with ASTM D1751:
a. Asphalt saturated fiberboard.
A. Examine joints indicated to receive joint sealers, with
installer present, for compliance with requirements for
joint configuration, installation tolerances and other
conditions affecting joint sealer performance. Do not
proceed with installation of joint sealers until
unsatisfactory conditions have been corrected.
A. Surface Preparation:
1. Joint and Surface Cleaning:
a. Clean out joints immediately before installing
joint sealers to comply with recommendations
of joint sealer manufacturers and the
b. Remove all foreign material from joint
substrates which could interfere with adhesion
of joint sealer, including dust; paints,
except for permanent, protective coatings
tested and approved for sealant adhesion and
compatibility by sealant manufacturer; old
joint sealers; oil; grease; waterproofing;
water repellents; water; surface dirt and
c. Clean concrete, masonry, unglazed surfaces of
ceramic tile and similar porous joint
substrate surfaces, by brushing, grinding,
blast cleaning, mechanical abrading, or a
combination of these methods to produce a
clean, sound substrate capable of developing
optimum bond with joint sealers. Remove loose
particles remaining from above cleaning
operations by vacuuming or blowing out joints
with oil-free compressed air.
d. Remove laitance and form release agents from
e. Clean metal, glass, porcelain enamel, glazed
surfaces of ceramic tile and other non-porous
surfaces by chemical cleaners or other means
which are not harmful to substrates or leave
residues capable of interfering with adhesion
of joint sealers.
2. Joint Priming: Prime joint substrates where
indicated or where recommended by joint sealer
manufacturer based on preconstruction joint sealer-
substrate tests or prior experience. Apply primer
to comply with joint sealer of manufacturer's
recommendations. Confine primers to areas of joint
sealer bond, do not allow spillage or migration
onto adjoining surfaces.
3. Masking Tape: Use masking tape where required to
prevent contact of sealant with adjoining surfaces
which otherwise would be permanently stained or
damaged by such contact or by cleaning methods
required to remove sealant smears. Remove tape
immediately after tooling without disturbing joint
3.03 ERECTION, INSTALLATION, APPLICATION
A. General: Comply with joint sealer manufacturers' printed
installation instructions applicable to products and
applications indicated, except where more stringent
B. Elastomeric Sealant Installation Standard: Comply with
recommendations of ASTM C962 for use of joint sealants as
applicable to materials, applications and conditions
C. Latex Sealant Installation Standard: Comply with
requirements of ASTM C790 for use of latex sealants.
D. Installation of Sealant Backings: Install sealant
backings to comply with the following requirements:
1. Install joint-fillers of type indicated to provide
support of sealants during application and at
position required to produce the cross-sectional
shapes and depths of installed sealants relative to
joint widths which allow optimum sealant movement
a. Do not leave gaps between ends of joint-fillers.
b. Do not stretch, twist, puncture or tear joint
c. Remove absorbent joint fillers which have
become wet prior to sealant application and
replace with dry material.
2. Install bond breaker tape between sealants and
joint-fillers, compression seals or back of joints
where adhesion of sealant to surfaces at back of
joints would result in sealant failure.
E. Installation of Sealants: Install sealants by proven
techniques that result in sealants directly contacting
and fully wetting joint substrates, completely filling
recesses provided for each joint configuration and
providing uniform, cross-sectional shapes and depths
relative to joint widths which allow optimum sealant
F. Tooling of Non-sag Sealants: Immediately after sealant
application and prior to time skinning or curing begins,
tool sealants to form smooth, uniform beads of
configuration indicated, to eliminate air pockets and to
ensure contact and adhesion of sealant with sides of
joint. Remove excess sealants from surfaces adjacent to
joint. Do not use tooling agents which discolor sealants
or adjacent surfaces or are not approved by sealant
1. Provide concave joint configuration per Figure 6A
in ASTM C962, unless otherwise indicated.
a. Use masking tape to protect adjacent surfaces
of recessed tooled joints.
G. Pourable sealants shall be applied by gun or by pouring,
filling the joint completely with a slight recessed
finish. Additional material will be added if low spots
H. Installation of Fire-Stopping Sealant: Install sealant,
including forming, packing and other accessory materials
to fill openings around mechanical and electrical
services penetrating floors and walls to provide fire-
stops with fire resistance ratings indicated for floor or
wall assembly in which penetration occurs. Comply with
installation requirements established by testing and
A. Clean off excess sealants or sealant smears adjacent to
joints as work progresses by methods and with cleaning
materials approved by manufacturers of joint sealers and
of products in which joints occur.
A. Protect joint sealers during and after curing period from
contact with contaminating substances or from damage
resulting from construction operations or other causes so
that they are without deterioration or damage at time of
substantial completion. If, despite such protection,
damage or deterioration occurs, cut out and remove
damaged or deteriorated joint sealers immediately and
reseal joints with new materials to produce joint sealer
installations with repaired areas indistinguishable from
END OF SECTION