Cathedral Ceiling Installation

VENTING INSTALLATION

Installation for Vertical Termination (Cont.)

VENTING INSTALLATION

Continued

7.Twist-lock the vent cap onto the last section of vent pipe and seal with high temperature silicone sealant as specified in the second warning statement on page 9.

Note: If the vent pipe passes through any occupied areas above the first floor, including storage spaces and closets, you must enclose pipe. You may frame and sheetrock the enclosure with standard construction material. Make sure and meet the minimum allowable clearances to combustibles. Do not fill any of the required air spaces with insulation.

1.Remove shingles or other roof covering as necessary to cut the rectangular hole for the support box. Mark the outline of the cathedral ceiling support box on the roof sheathing using the locating hole as a center point.

2.Cut the hole 1/8" larger than the support box outline (see Figure 26).

3.Lower the support box through the hole in the roof until the bottom of the box extends at least 2" below the ceiling (see Figure 26). Align the support box vertically and horizontally using a level. Temporarily tack the support box in place through the inside walls and into the roof sheathing.

4.Using tin snips, cut the support box from the top corners down to the roofline and fold the resulting flaps over the roof sheath- ing (see Figure 27). Apply a bead of non-hardening mastic around the top edges of the support box to make a seal between the box and the roof. Nail in place with roofing nails. Remove any com- bustible material that might be inside of the support box.

5.Complete the cathedral ceiling installation by following the same procedures outlined in steps 2 through 7 for Flat Ceil-