Werner AA1510 Instructions D'installation page 18

Section 1.5 (Continued)
Framing the Rough Opening
Installing Headers
If no joists have been cut, go to "Single Headers" below.
If any joists have been cut, go to "Double Headers" on page 18.
Single Headers
STEP 1. Measure the header length "H" between
the joists (See Figure 11).
STEP 2. Cut 2 headers this length. Use
joist-sized lumber.
STEP 3. Place one of these headers at one end of
your chosen location (See Figure 12). The
header must fit snugly between the joists.
Hammer it into position if necessary; if it is
more than 1/16" too long, trim it. If it is
more than 1/16" too short, cut another piece.
STEP 4. Square the header to one joist and drive
3 nails (16d) through the joist and into the
header. Check for squareness and drive
3 nails (16d) through the other joist and
into the header (See Figure 12). It is very
important that header board is vertically
square as well as horizontally square to
side joists.
STEP 5. Position the second header at least 24" from
the first one and repeat Step 4 (See Figure 13).
STEP 6. The frame for the rough opening requires
four sides. The headers make up two of
those sides. If your ceiling joists are spaced
so that they make up the other two sides of
the rough opening, check the opening for
squareness by measuring across the
diagonals. The measurements should be
within 1/8" to be considered square
(See Figure 13).
If your ceiling joists do not make up the
other two sides of the rough opening, you
need to install one or two additional pieces
of lumber to frame the other side(s) of the
rough opening, go to "Installing Stringers"
on page 19.
17
H
Figure 11
Joists
Drive 3 Nails (16d) into
each end of the Header
Figure 12
Diagonal
Measurements
Nails
Figure 13 How to check for square
Header
Nails
Header
At
least
24"
Header