Desa CDVBN(A), CDVBP(A) Cathedral Ceiling Installation, Level Cathedral ceiling support box

OWNER’S MANUAL

VENTING INSTALLATION

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If area above is a room, install firestop above framed hole.

If area above is not a room, install firestop below framed hole.

Figure 31 - Installing Firestop

3.Cut a hole in the roof using the locating hole as a center point. (Cover any ex- posed open vent pipes before cutting hole in roof.) The 10"x10" hole must be measured on the horizontal; actual length may be larger depending on the pitch of the roof. There must be a 1" clearance from the vent pipe to combus- tible materials. Frame the opening as shown in Figure 22 on page 12.

4.Connect a section of pipe and extend up through the hole.

Note: If an offset is needed to avoid obstructions, you must support the vent pipe every 3 feet. Use wall straps for

this purpose (see Figure 30, page 14). Whenever possible, use 45° elbows in- stead of 90° elbows. The 45° elbow of- fers less restriction to the flow of the flue gases and intake air.

5.Place the flashing over the pipe section(s) extending through the roof. Secure the base of the flashing to the roof and framing with roofing nails. Be sure roofing material overlaps the top edge of the flashing as shown in Figure 30, page 14. There must be a 1" clearance from the vent pipe to combustible materials.

6.Continue to add pipe sections until the height of the vent cap meets the mini- mum building code requirements de- scribed in Figure 18 on page 9. Note: You must increase vent height for steep roof pitches. Nearby trees, adjoining rooflines, steep pitched roofs, and other similar factors may cause poor draft or down-drafting in high winds. Increasing the vent height may solve this problem.

7.Twist-lock the vent cap onto the last section of vent pipe and seal outer pipe connection with high temperature sili- cone sealant as specified in the second warning statement on page 10.

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 enclo- surewithstandardconstructionmaterial.Make sure and meet the minimum allowable clear- ances to combustibles. Do not fill any of the required air spaces with insulation.

Cathedral Ceiling Installation

1.Remove shingles or other roof cover- ing as necessary to cut the rectangular hole for the support box. Mark the out- line of the cathedral ceiling support box on the roof sheathing using the locat- ing hole as a center point.

2.Cut the hole 1/8" larger than the sup- port box outline (see Figure 32).

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 32). 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 sheathing (see Figure 33). 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 combustible material that might be in- side of the support box.

5.Complete the cathedral ceiling installa- tion by following the same procedures outlined in steps 2 through 7 for Flat Ceiling Installation, pages 14 and 15.

Level

Cathedral ceiling support box

2" minimum below finished ceiling

Cut hole 1/8" larger than support box when projected onto roofline

Figure 32 - Cathedral Ceiling Support Box Installation

Non-hardening Mastic under all edges of support box before nailing

Figure 33 - Installed Cathedral Ceiling Support Box

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