1.
Mark out the rough opening size for your unit according to TABLE A.
Note that the finished metal
trim extends about 2” beyond the rough opening when the unit is installed (Figure 2). Allow
clearance for this on all four sides.
2.
Cut the rough opening through the ceiling material.
Figure 2
Preparing the Opening
Most attic stairs will be installed parallel to the ceiling joists (Figure 3). In cases where they are installed
perpendicular to joists (Figure 4), some joists will need to be cut and tied-in to other joists with “headers”
of the same dimensions as the joists and will form the box frame into which the stair will be secured.
Before cutting any joists, watch out for electrical wiring.
If your attic is constructed using trusses, DO NOT CUT CEILING JOISTS WITH-
OUT CONSULTING AN ENGINEER AND OBTAINING APPROVAL.
WARNING
Framing the Opening
Page 4
July 2014
Figure 3
Figure 4
HEADERS
HEADERS