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Rough Opening Statement


The Kolbe standard rough opening dimensions published for our products are provided as a guideline to maintain a minimum 1/4" space between the window or patio door and the building structure. In certain situations for our wood, aluminum clad and vinyl products, Kolbe recommends a gap larger than our published 1/4" standard:

  • When installation clips are used, the gap should be increased to 1/2" on the sides, top, and bottom of the unit.
  • When mulls are installed in the opening, the gap all around should be increased to 1/2". For installation consistency, the same gap should be used on all units in the project.
  • If a sill pan drainage system is used, the gap should be increased to 1/2" on the top and the bottom of the unit.

Because every installation is different, Kolbe strongly recommends consultation with the local supplier or an experienced contractor, architect or structural engineer prior to the installation of any Kolbe product.

Installation of Kolbe products, including size of rough openings, method of attachment, fastener selection, and code compliance are the sole responsibility of the architect, building owner, contractor and/or consumer. Unless otherwise specified, if units are ordered by rough opening, Kolbe will size the units using our standard minimum 1/4" gap — regardless of the options or construction of the product ordered.

Calculating Opening Dimensions for:

Most VistaLuxe, Ultra, Heritage, Classic, Latitude and Windquest Series Products

  Single Frame Width Overall Multiple Frame Width Single Frame Height Overall Multiple Frame Height
Rough Opening (without brickmould casing) Frame width + 1/2" Add together the overall frame widths of each unit plus 1/2" Frame height + 1/2" Add together the overall frame heights of each unit plus 1/2"
Masonry Opening (without brickmould casing) Frame width + 1/2" Add together the overall frame widths of each unit plus 1/2" Frame height + 1/2" Add together the overall frame heights of each unit plus 1/2"

Calculating Opening Dimensions for:

Ultra & Heritage Series Sterling Double Hungs
Ultra, Heritage & Classic Series Traditional Double Hungs
Ultra, Heritage & Classic Series Double & Triple Sliders

  Single
Frame Width
Overall Multiple Frame Width Single
Frame Height
Overall Multiple Frame Height
Rough Opening (without brickmould casing) Frame width + 1/2" Add together the overall frame widths of each unit plus 1/2" Frame height + 9/16" Add together the overall frame heights of each unit plus 9/16"
Masonry Opening (without brickmould casing) Frame width + 1/2" Add together the overall frame widths of each unit plus 1/2" Frame height + 9/16" Add together the overall frame heights of each unit plus 9/16"
NOTE: For Heritage Series products, unit dimensions and frame dimensions are the same.

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