Roll out the foil across the deck

Start at the eave and roll RoofingFoil™ + Underlayment horizontally across the deck, working your way up toward the ridge.

Fasten to the deck

Attach with plastic cap roofing nails — these are the preferred fastener for a secure hold. You don't need a bunch of fasteners, you're just holding down the edges mostly since the battens will hold the rest in place.

Staples work if you don't have cap nails, but aren't the first choice for long-term performance. 

Overlap each row 4–6"

As you work up the roof, overlap the previous row by at least 4" (up to 6") to keep the barrier continuous and water-resistant.

Install the batten system on top of the foil

Attach your battens directly over the foil. The battens lift the metal roof and create the required ½" minimum air gap — no extra steps needed.

If you want to vent the roof, you can, but it's not critical to the foil working. More info here: Info About the Required Air Gap 

Install the metal roof over the battens

Proceed with your standard metal roofing install. The foil is now properly positioned to reflect radiant heat before it can pass into the structure below.

Roll out the foil over the framing

Span the foil across the top of the framing members before any metal panels go on. The foil will naturally drape slightly between members — this sag is what creates the required air space. Aim for it to be about the 4"-6" of a drape at the center of the two framing pieces.

Fasten the foil to the framing

For wood framing, use plastic cap nails or staples. For metal framing, use screws or double-sided adhesive tape to hold the foil in place until the metal roof panels are attached on top.

Overlap each row 4"–6"

Same rule as Scenario A — overlap each row by at least 4" as you work from the eave to the ridge.

Install the metal panels directly over the foil

The panels compress the foil at each attachment point while the foil spans freely between framing members, maintaining the minimum ½" air space across the roof.