Installing Weatherstripping On Metal Double-Hung Windows

CSI Division
Division 3 - Concrete
Section
Metal Windows
Last Modified

Technical Procedures Disclaimer

Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.

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We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.

PART 1–GENERAL

1.01 SUMMARY

  1. This procedure includes guidance on installing various types of weatherstripping on metal double-hung windows.
  2. It is best to use the thinnest material available to fill the space where air is entering. Weatherstripping that is too thick can spring hinges and can create additional gaps.
  3. To help seal a structure against the elements, weatherstripping can be applied to window and door openings. The type and manner of weatherstripping installation is very important when applied to historic structures. The Regional Historical Preservation Officer (RHPO) should be consulted before weatherstripping type is chosen or applied.
  4. 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).

PART 2–PRODUCTS

2.01 Manufacturers

  1. Accurate Metal Weatherstrip Co. Inc. www.accurateweatherstrip.com/index.html
  2. Pemko Manufacturing Co. Inc. www.pemko.com

2.02 Materials

  1. Metal Integral Weatherstripping (see manufacturers in section 2.01 or approved equal).
    1.  Most effective and durable type of weatherstripping
    2.  Most difficult to install, requiring some degree of carpentry skill to accomplish.
      -OR-
      Spring Metal Weather-stripping (see manufacturers in section 2.01 or approved equal).
      1. Available in bronze, brass or stainless steel. Also available in spring plastic.
      2. Designed with an integral friction-fit mounting clip.
      3.  Attached by nails to the side channels of the window frame.
      4. No applied glue necessary.
      5. Tight closure insured by thin metal.
      6. Window must be painted first to prevent galvanic corrosion.
      7.  Usually applied around entire perimeter of window; On casements, all but hinge side. -OR-
        Adhesive-Backed Plastic Spring or Plastic `V’ stock or Vinyl Strips is a plastic version of spring metal weatherstripping. It is attached by adhesive. Channels must be thoroughly cleaned before installation because the adhesive will not stick to dirty surfaces. The plastic does not last as long as metal.
        1. Applied after painting.
        2.  in “V” configuration.
        3.  Usually glued to frame; Some have adhesive backing.
        4.  Increased thickness due to adhesive; therefore, not always appropriate.
          -OR-
    3. Compressible Foam Tape:
      NOTE: ADHESIVE-BACKED FOAM STRIP SHOULD NOT BE USED AT ALL.
      1.  Best for large windows where there is a slight bending or distortion of the sash.
      2. Adhesive or plain (to be applied with glue) back.
      3. Useful for gaps up to 1/4” wide.
      4. More frequent replacement required than for spring metal or vinyl strips. 
        -OR-
        Caulking or Sealant Bead and Polyethylene Bond-breaker Tape.
        -OR-
    4. Tubular Gasket Weatherstripping:
      NOTE: TUBULAR GASKET WEATHERSTRIPPING IS AN EFFECTIVE OPTION; BUT, IT IS UNSIGHTLY. THIS TYPE OF WEATHERSTRIPPING SHOULD NOT BE USED.

2.03 EQUIPMENT

  1. Carpenter’s tools needed to remove sash
  2. Tin snips or radial arm saw
  3. Table saw or router
  4. Putty knife

PART 3–EXECUTION

3.01 PREPARATION

  1. Surface Preparation:
    1. Using a heat gun and thin putty knife, break existing paint film and remove sashes, see 08610- 03-R “Unsticking a Wood Window Sash” for guidance.
    2. Strip paint from sash jambs, sill and parting bead.
    3. Caulk and fill cracks that could trap moisture.
    4. Replace sash cord if needed, see 08760-01-R “Replacing a Sash Cord or Chain” for guidance.

3.02 ERECTION, INSTALLATION, APPLICATION

  1. For Metal Integral Weatherstripping: (follow manufacturer’s instructions)
    1. Measure and cut metal for top and upper sides of sash. The metal can be cut with tin snips or a radial arm saw with metal cutting blade. Miter corners.
    2. With a table saw or router, cut slots in sashes to accept weatherstripping.
    3. Fit metal into upper jambs and head of window frame leaving space at sash pulley location and reinstall upper sash.
    4. Install weatherstripping to the lower window frame, installing it at the jambs before the sill. Slip lower sash into position from above.
    5. Check for binding in both sashes; reinstall stops.
  2. For Spring Metal Weatherstripping: (follow manufacturer’s instructions)
    1. Nail strips to sash channels being careful not to cover pulleys in upper channel.
    2. Nail full width strip to underside of bottom sash.
    3. Slightly nail strip to inside edge of upper sash.
  3. For Caulking or Sealant Bead and Polyethylene Bond- breaker Tape: (follow manufacturer’s instructions) NOTE: THIS PROCEDURE IS EFFECTIVE FOR ALL TYPE OF METAL WINDOWS WITH VARYING DEGREES OF AIR INFILTRATION.
    1. Clean window frame thoroughly using a solvent.
    2. Allow to dry and prime.
    3. Apply a bead of silicone caulk.
    4. Apply bond breaker tape to operable sash covering metal section where contact will occur.
    5. Close window and allow sealant to set (2-7 days depending on the temperature and humidity).
    6. Open window and remove bond breaker tape; The bead should have taken the shape of the gap. -OR- If the window is never opened, it may be sealed shut with acrylic latex caulk. If the window is seldom opened, a roll- type temporary caulk may be used.
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Last updated: Dec 15, 2017
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