Step 1: Rough Opening and Framing Requirements (cont.)
1/2″
1/2″
1/4″
1/4″
Rough Opening | Masonry Opening |
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Figure 2: Preparing openings for concrete block openings.
5.Rough openings1 (RO) should be 1″ (25) wider than the outside measurement of the frame and 1/2″ (13) higher. Masonry openings (MO) should be 1/2″ (13) wider than the outside measurement of the frame or casing and 1/4″ (6) higher than the outside measure- ment of the frame or casing. When framing rough opening, care should be taken to ensure the sill plate is level and the opening is square, straight and plumb. See figure 2.
ATTENTION: Be aware that use of rigid sill pans and other barriers will decrease the rough opening height clearance. Adjust opening dimensions accordingly.
CAUTION! If the previous conditions are not met, the installer must take corrective actions to alter the opening(s) before
proceeding. It is also essential that the sheathing behind the wall be a solid surface to ensure that the unit can be secured firmly to the wall.
NOTE: On standard wood frame construction with brick veneer, make sure there is at least 1/2″ (13) between bottom of window sill (or eventual placement of the window) and the top row of brick to avoid “brick bind”.
1Rough opening gap must be no more than 1/4″ for products certified for use in IZ4 regions.
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