Window and Storm Sash Terminology
STORM SASH OPENING: The Width and Height of the window opening that the storm sash fits into. For Double-Hung windows, the storm sash opening width is measured between the exterior side casings. The sash opening height is measured from the underside of the head casing to the sill at the OUTSIDE of the casing, or OUTSIDE face of the storm sash. CORRECT HEIGHT MEASUREMENT IS IMPORTANT to obtain properly sized sash!
SASH SIZE: The actual with and height of the sash. Unless otherwise stated, we usually build storm sash to the Sash Opening Size so that a small amount of field trimming is necessary to get a good fit of the sash in its opening. Old window openings are rarely perfectly plumb and square, so the new storm sash should be trimmed to obtain a uniform gap of approximately 1/16" between the sash and frame on all 4 sides.
STANDARD STORM SASH SIZES: Standard sized 2-light storm sash have standard glass sizes of even-inch width x even inch height. The overall storm sash dimensions are 4" wider than the glass width and 6-1/2" to 8" higher than 2x the glass height. Minor adjustments can be made for windows that are SLIGHTLY wider or narrower than standard, but if the sash opening width varies by more than plus or minus 3/8" from an even-inch width, or the sash height does not accept a standard even-inch glass height we will need a detailed explanation showing glass sizes.
STANDARD STORM SASH THICKNESS: Standard storm sash thickness is 1-1/8". Other thicknesses are specials.
DAYLIGHT OPENING: The area of glass visible in a glazed sash. For STANDARD STORM SASH The GLASS SIZE is 5/16" wider and 5/16" higher than the daylight opening.
SASH STICKING: The inner arris of the sash is moulded with a profile on the interior edge and a GLASS RABBET on the exterior edge to receive the glass.
GLASS RABBET: The rabbet on the exterior face of the inner arris of the sash ploughed to receive the glass. Standard Storm Sash glass rabbets are 3/16" wide by 3/8" to 7/16" deep. Western standard sash have 1/4" wide glass rabbets. SASH BARS have glass rabbets ploughed on both edges of the exterior face to receive glass.
SASH BAR: A narrow glazing bar in a sash for the purpose of cutting the sash into multiple or DIVIDED LIGHTS. Standard Storm Sash for Double-Hung Windows ard divided into 2 lights by one horizontal sash bar which aligns with the CHECK-RAIL of the Double-Hung Window. Standard storm sash have a 1-1/4" wide sash bar with a 7/8" FACE MEASURE.
DIVIDED LIGHT SASH: A sash cut up into multiple lights by the addition of sash bars. Common divided-light sash patterns are 2/2 (Victorian), 4-light, 6-light, 8-light, and 12-light. Standard Storm Sash are 2-light for all double-hung window light arrangements except for 2/2 Victorian Windows which typically are odd-inch widths and utilize 4-light storm sash with even inch glass widths.
For more information on any of the following items, click linked text or image below.
Daylight Opening and Glass Opening Sizes
Illustration Of Daylight Opening and Glass Opening
Daylight Opening and Glass Opening Measurements
How to Obtain Correct Layout for Non-Standard Sash or Glass Heights
Determing Rail and Bar Widths, Glass Heights, and Sash Height
Vertical Section of Sash showing Rail and Bar Widths and Opening Heights
Finish Width and Face Measure of Sash Components
Section of Sash Rail or Stile and Sash Bar Illustrating Finish Width and Face Measure
Face Measure and Finish Width of Sash Bar