Kilian Hardware's Interlocking Weatherstripping is made in the United States to the highest quality standards. For double hung windows, interlocking weatherstrip is used on the head, sill, jambs, and meeting rail. It is 230 alloy, 85% copper, and 15% zinc, 1/4 hard, and .016” thick.
Which Interlocking Weatherstrip Should I Use?
The sizes of interlocking weatherstrip that you should use depends on the thickness of your sash, the size of the window opening, and the widths and heights of your sashes.
For each double hung window with two movable sashes, you will need 8 pieces of weatherstrip:
- 1 piece of head weatherstrip (placed at the top of the window)
- 2 pieces of jamb weatherstrip for the upper sash (placed at the sides of the upper sash)
- 2 pieces of jamb weatherstrip for the lower sash (placed at the sides of the lower sash)
- 2 pieces of meeting rail weatherstrip (placed at the junction of the two sashes)
- 1 piece of sill weatherstrip (placed at the bottom of the window)
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| Head Weatherstrip | Jamb Weatherstrip | Meeting Rail Weatherstrip | Sill Weatherstrip |
Weatherstrip lengths:
- Head weatherstrip: length equal to the length of the top of the window opening
- Jamb weatherstrip for the upper sash: length equal to the height of the upper sash plus 1/4"
- Jamb weatherstrip for the lower sash: length equal to the height of the lower sash plus 1/4"
- Meeting rail weatherstrip: length equivalent to the space between the parting beads, or if meeting rail blocks are used, the space between the meeting rail blocks
- Sill weatherstrip: length equal to the length of the bottom of the window opening
Weatherstrip widths:
- Head weatherstrip: width determined by the thickness of the sash. For sashes up to 1-7/8" thick, the 1" wide head weatherstrip should be used. For sashes greater than 1-7/8" thick, the 1-3/8" wide head weatherstrip should be used.
- Upper jamb weatherstrip: width nearest to the thickness of the sash. For example, for a 1-3/8" thick sash, the width of the upper jamb weatherstrip should be 1-3/8". Available sizes of jamb weatherstripping are 1-3/8", 1-3/4", 2", 2-1/4", and 2-1/2".
- Lower jamb weatherstrip: width one size up from the thickness of the sash. For example, for a 1-3/8" thick sash, the lower jamb weatherstrip should be 1-3/4" wide. Available sizes of jamb weatherstripping are 1-3/8", 1-3/4", 2", 2-1/4", and 2-1/2".
- Meeting rail weatherstrip: the standard size fits most double hung windows.
- Sill weatherstrip: width nearest to the thickness of the sash. For example, for a 1-3/8" thick sash, the width of the sill weatherstrip should be 1-3/8". Available sizes of sill weatherstripping are 1", 1-3/8", 1-3/4", 2", and 2-1/4".
Bronze or zinc:
The bronze interlocking weatherstrip offers superior aesthetics. However, there is no functional difference between the bronze and the zinc interlocking weatherstrip.
Style of jamb weatherstrip:
The jamb interlocking weatherstrip is available with or without a return flange. In general, we recommend using the jamb weatherstrip without the return flange. However, if you are replacing existing weatherstrip that has the return flange, you may want to replace it with new weatherstrip with the return flange.
Style of meeting rail weatherstrip:
Two styles of meeting rail weatherstrip are available: the standard style and the hemmed hook style. In general, the standard style (M1/M2) is recommended to provide the best seal. However, if you are replacing hemmed hook style meeting rail weatherstrip and want to be consistent, you can use the hemmed hook style (M3/M4).
How to nail:
When installing head, jamb, and sill weatherstrip, nails should be spaced by about 3". Nails should be placed along both long edges of the weatherstrip. When installing meeting rail weatherstrip, nails should be spaced by about 1.5". Meeting rail weatherstrip is nailed on the edge of the long end of the hook. For bronze interlocking weatherstrip, we offer solid bronze nails and copper plated steel nails. Solid bronze nails are recommended in coastal environments to prevent rust. In other environments, copper plated steel nails are sufficient. We offer 3/4" copper plated steel nails, 7/8" copper plated steel nails, 3/4" solid bronze nails, and 1" solid bronze nails. The length of nail you use depends on your preference. In most cases, 3/4" nails are sufficient, and the 3/4" length is most commonly used. For zinc weatherstrip, we offer 3/4" stainless steel nails.
Recommended for a 1-3/8" thick sash:
- Head weatherstrip: 1" wide 2P bronze or zinc weatherstrip
- Upper jamb weatherstrip: 1-3/8" wide 4C bronze or zinc weatherstrip
- Lower jamb weatherstrip: 1-3/4" wide 7C bronze or zinc weatherstrip
- Meeting rail weatherstrip: M1/M2 bronze or zinc weatherstrip
- Sill weatherstrip: 1-3/8" wide 4P bronze or zinc weatherstrip
Recommended for a 1-3/4" thick sash:
- Head weatherstrip: 1" wide 2P bronze or zinc weatherstrip
- Upper jamb weatherstrip: 1-3/4" wide 7C bronze or zinc weatherstrip
- Lower jamb weatherstrip: 2" wide 9C bronze or zinc weatherstrip
- Meeting rail weatherstrip: M1/M2 bronze or zinc weatherstrip
- Sill weatherstrip: 1-3/4" wide 7P bronze or zinc weatherstrip
Recommended for a 2" thick sash:
- Head weatherstrip: 1-3/8" wide 4P bronze or zinc weatherstrip
- Upper jamb weatherstrip: 2" wide 9C bronze or zinc weatherstrip
- Lower jamb weatherstrip: 2-1/4" wide 10C bronze or zinc weatherstrip
- Meeting rail weatherstrip: M1/M2 bronze or zinc weatherstrip
- Sill weatherstrip: 2" wide 9P bronze or zinc weatherstrip
Recommended for a 2-1/4" thick sash:
- Head weatherstrip: 1-3/8" wide 4P bronze or zinc weatherstrip
- Upper jamb weatherstrip: 2-1/4" wide 10C bronze or zinc weatherstrip
- Lower jamb weatherstrip: 2-1/2" wide 11C bronze or zinc weatherstrip
- Meeting rail weatherstrip: M1/M2 bronze or zinc weatherstrip
- Sill weatherstrip: 2-1/4" wide 10P bronze or zinc weatherstrip