Home and Garden | Install Double Roll Covers - Roofing

Buy double coverage roll roofing (sometimes called selvage roofing) for those roofs that are nearly flat (up to 1 in 12).

This material is applied with a 19-inch overlap, called the selvage, and a 17-inch mineral-coated exposure.

Selvage can be applied over shingle or roll roofing, but it is best to remove old roofing, repair the sheathing, and install drip edges.

Each roll covers 51 square feet. Because of the thorough overlap, it provides a double layer of roofing. Be sure to purchase the type applied with cold cement rather than hot asphalt.

PROJECT BASICS

Project: Moderate
Estimated Project Time: 1 or 2 days
Start Tips: It's best to remove old roofing, repair the sheathing, and install drip edges before applying double coverage roll roofing
Safety Tips: Make sure your ladder to the roof is securely braced
Recommendation: Do-it-Yourself

TOOLS & MATERIALS

Double coverage roll roofing	Roofer's roller (can be rented)
Roofing cement	Galvanized nails
Bucket	Hammer
Trowel	Hook blade utility knife
Broom-handled brush	Chalk line

Fig. 1

INSTRUCTIONS

1) Apply the starter strip
Double coverage roofing is applied directly to sheathing. Cut away the 17-inch mineral-coated section to be used as the starter strip.

Using a broom-handled brush, apply a 17-inch-wide layer of roofing cement along the eaves (Fig. 1). Then press the starter strip into the cement and roll it with a roofer's roller (these can be rented).

Nail in two rows of nails at 12-inch intervals across the surface.

Fig. 2

2) Add the course
Position the first course over the starter strip. Nail it in place with two horizontal rows of nails. Position the rows 4-1/2 inches and 13 inches from the top of the course. Space nails in rows about 12 inches apart.

Roll back the sheet and coat the selvage surface thickly with roofing cement. (Fig. 2)

Fig. 3

3) Seal vertical overlaps
Vertical seams are cemented, rather than nailed, and overlap by 6 inches.

Nail the first sheet along the edge, spacing nails 4 inches apart and 1 inch in from the edge. Apply cement to the overlapping sheet, covering the first sheet 5-1/2 inches in from its nailed edge (Fig. 3).

Fig. 4

4) Seal hips and ridges
Finish the hips and ridges by repeating the same procedure in miniature. Cut sections 12 inches wide from a roll of double coverage roofing (include both the selvage and exposed areas).

Snap a line and apply a starter strip using only the selvage section of one piece. Nail the selvage section, spacing the nails at 4-inch intervals. Hammer one additional nail 1 inch in from the edge.

Trowel on cement and add the next section as you would a shingle. (Fig. 4)

Fig. 5

5) Trim the rakes
As with roll roofing, it is easiest to let the roofing overhang the rake and trim it after the roof is covered.

Strike a line so that 1/4 inch of roofing overhangs the drip edge. Use a hook blade utility knife to trim the rake. (Fig.5)

Installing Double Coverage Roll Roofing