How to Install Solar Board Insulation

Nail 1-inch furring along the side of all rafters and gables in attic where they face the roof of the house using a hammer and 8d nails.

Measure the size of the rafters where you plan to install the solar insulation board with a measuring tape, transfer these measurements to the insulation and cut it to size with a utility knife.

Place a layer of shingle underlayment or #15 roofing felt onto your roof deck to protect the solar board from the elements until you can install the shingles. Start driving the plastic capped roofing felt nails 12 inches in from the outer edge of the roofing felt. Position them a staggered pattern, alternating between a row of nails 9 inches apart and another row of nails 18 inches apart to attach the felt securely to the roof.

Check the alignment of the rafters with a level and drafting square to ensure they are square and even. Set the solar board panels foil side down, facing the interior of the attic, laying them on the gables of your attic. Plan to allow an airspace of 3/4 inch between the foil surface and other attic building materials; allow 1/8 inch between the panel's ends and edges. Use a level to ensure you have installed the panels squarely and lined them up uniformly, then nail them into place.