CAUTION: Use only genuine Ondura nails for installing sheets and tiles (tiles at eave and ridge only). See Fig. 5. Other types of nails may not provide sufficient hold-down strength.

Drive Ondura nails only through the top of corrugations. And drive perpendicular into purlins-not at an angle-so the rubber washer is snugly in contact with the sheet. See Fig. 6. Don't overdrive or underdrive nails. Slight hand pressure on a nailed-down corrugation should not separate sheet from washer contact.

To pull a nail from a sheet, use a claw hammer and a 1 1/2" wood dowel or pipe. (This technique minimizes the chance of damaging the sheet). Put the dowel or pipe in the valley next to the crown with the nail to be pulled. Then use the dowel or pipe as a leverage point for pulling the nail. See Fig. 7.

All roofing requires ventilation. It's a false economy to try to conserve heat in an uninsulated building by closing off ventilation openings. That's because poor ventilation can cause excessive heat buildup in the summer and severe condensation problems and dripping in the winter, which in turn can cause deterioration of roof framing and covering materials.

See Fig. 36* for suggestions on how to take advantage of Ondura's corrugated design and Ridgeline Ridge Vents and Ondura Ventilated Closure Strips to assist ventilation.

CAUTION: Improper or inadequate ventilation will void warranty.

*This may not be sufficient ventilation for all buildings, especially animal confinement structures. Check with an engineer.

See fig. 4 in Getting Started

1. From the comer where the eave and rake meet, measure along the eave 48 inches and mark.

2. From the corner of the rake and the ridge, measure along the ridge 48 inches, plus or minus the out-of-square distance determined earlier, and mark.

3. Snap a chalk line between these marks for sheet alignment.

4. To establish a drip-edge overhang of all eave sheets, drive nails into the corner rafters at either end of the eave, and stretch a line between them 1 3/4" out along the length of the eave. Visually align each sheet of the eave row with this string for a uniform drip-edge.

5. Now you can install the first sheet. Starting at the rake edge of the sheet, nail down the first corrugation at every purlin so that this edge is aligned with the rake.

6. Now flex the sheet so its opposite edge aligns with the chalk line. Nail along the crown of the second corrugation from this edge, then nail the remainder of the sheet (see Fig. 12 and 13). If using closure strips, install before nailing eave.

NOTE: The flexibility of Ondura sheets and tiles may lead to misalignment or "spreading" if care is not taken to keep sheet and tiles at nominal width (48") during installation.

1. From the corner where the eave and rake meet, measure along the eave 48 inches and mark.

2. From the corner of the rake and the ridge, measure along the ridge 48 inches and mark.

3. Snap a chalk line between these marks for sheet alignment.

4. To establish a drip-edge overhang of all eave sheets, drive nails into the corner rafters at either end of the eave, and stretch a line between them 1 3/4" out along the length of the eave. Visually align each sheet of the eave row with this string for a uniform drip-edge.

5. Starting at the eave/rake corner, fasten the rake corrugation of the first sheet of Ondura at each purlin up the rake (see Fig. 8 nailing pattern).

6. Now align the opposite edge of the sheet with the chalk line. Nail in place (see Fig. 8) along the second corrugation from the chalk line to allow for the side lap of the next sheet. In using closure strips, install before nailing eave.

NOTE: The flexibility of Ondura sheets and tiles may lead to misalignment or "spreading" if care is not taken to keep sheet and tiles at nominal width (48") during installation.

The second row can be installed so that all side-laps meet lower sheets in the middle, or so that all side-laps line up from row to row up the slope of the roof to offset the sidelap of one row from the other.

To stagger the sidelaps from row to row, begin the second row with a sheet cut in half along its length (see Fig. 10). Be sure to cut the sheet in its valley. Since the edge of this first sheet won't line up with the chalk line of the first row, make a new line half a sheet's distance in from the rake. Now install the remainder of the second row using full sheets and new chalk lines (every 44") for alignment. Lap the lower end of the second sheet row 7 inches over the upper end of the first row. And be sure the center of each lap is over the center of the purlin beneath (see Fig. 9).

Remember: The flexibility of Ondura sheets may lead to "spreading". This can be helpful if you need to "stretch" the width of the sheet or it can cause problems if done inadequately by pressing down on the sheets as you install.

To have all side-laps of all rows line up, simply begin the second row with a full sheet, installing this and subsequent rows in the same manner as you did the first (see Fig. 11).

NOTE: For instruction on installing the ridge and other installation tips, go to FINISHING.