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 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.