Replacing Deteriorated Caulk At Masonry Surfaces

Procedure code:
National Capitol Region Specifications - Old Executive Off
Thermal and Moisture Protection
Joint Sealers
Last Modified:




    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

         3.   Submittals

         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,


    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
         the formula.


    A.   Samples:

         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.


    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.


    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.


    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
Last Reviewed 2012-02-24