How to Install a DuPont Elvaloy Roof Liner

Prep Work

• Before installing a DuPont Elvaloy roof liner, the underlying roof deck must be clean, smooth, dry and free of defects. Depending on your roof’s condition, you may need to prep the roof deck by brushing it clean, sanding it smooth and allowing it to dry. You may also need to repair or replace damaged areas. To avoid potential problems with condensation, ensure the space beneath your roof’s sheathing is ventilated before installing the roof liner.

Overlapping

• DuPont recommends rolling out sheets of the roof liner horizontally, as if they were giant shingles. This means the bottom edges of successive liner sheets should overlap the top edges of previous liner sheets. More specifically, these overlaps should be 4 inches in size. When installing new liner sheets adjacent to an existing row of sheets, offset the new sheets by 6 feet so the seams from the new overlaps don’t line up with the seams of the existing overlaps. In addition, the ends of new rows of liner sheets should overlap the ends of existing rows of liner sheets by 6 inches.

Special Considerations

• Prior to installing the large, horizontal sheets of DuPont Elvaloy roof liners, you should line the roof valleys, or indentations, with small sections of liner. Lap the ends of horizontal liner sheets over these smaller valley sections of liner by 6 inches. At the hips and ridges of the roof, the roof liner sheet from one roof plane should overlap the sheet from the adjacent roof plane by 6 inches.

Fastening

• Fasten DuPont Elvaloy roof liner to the underlying roof sheathing with metal or plastic cap-staples or cap-nails that have minimum diameters of 1 inch. The legs of these staples and nails must be a minimum of 3/4 inch in length. Space the fasteners at 8 inches on center along the areas where liner sheets overlap and in a single row 24 inches on center in the field of sheets. "On center" is the measurement between the center of one member and the center of an adjacent member.

Precautions

• For best results, don't stretch DuPont Elvaloy roof liner during installation; keep it wrinkle-free and taut. Don't apply the liner on wet or frost-covered sheathing nor should you walk on the liner if it's wet or frosty. Don't walk on the liner until you have fastened it properly with staples or nails.