How to Install RoofingFoil™ Under a Tile Roof

Tile roofing that uses battens, counter-battens, or has a naturally occurring air space because of the shape of the tile makes adding a radiant barrier very simple. The goal is to get the foil down before the battens, then continue the normal installation process.

Every radiant barrier needs an air gap to work. ½" is the minimum — the air space does not need to be vented to be effective, though ventilation helps cool the roof further.
What you'll need
Plastic cap roofing nails
Utility knife or scissors
Tape measure
Staple gun (backup option)
 Secondary waterproofing membrane (for tile roofs only)
Scenario A

Curved tile (Spanish / clay tile)

With curved tiles like Spanish clay tile, the shape of the tile itself creates the required air gap — no batten system needed. The foil goes directly to the deck below the tiles.

1

Install the secondary waterproofing membrane

Lay down your secondary waterproofing layer on the deck first, per standard tile roofing practice.

2

Roll out RoofingFoil™ + Underlayment over the membrane

Starting at the eave, roll the foil horizontally across the deck over the secondary membrane, working up toward the ridge.

3

Fasten to the deck

Attach with plastic cap roofing nails — the preferred fastener. Staples work as a backup but are not ideal for long-term performance.

4

Overlap each row 4–6"

Overlap each row by at least 4" (up to 6") as you work up the roof to keep the barrier continuous and water-resistant.

Tip: More overlap = better moisture protection. Don't go under 4".
5

Install the curved tiles

Proceed with your standard curved tile install. The curved shape of the tile naturally creates the ½"+ air gap between the tile and the foil below — no battens required.

Roof layer order — top to bottom
Curved tiles outermost
Air gap (tile shape) ½"+ min.
RoofingFoil™ + Underlayment
Secondary waterproofing membrane
Decking
Attic / interior innermost
RoofingFoil installed under curved clay tile roof

RoofingFoil™ installed under Spanish clay tiles — the curved profile creates the air gap automatically.


Scenario B

Flat tile with batten system

For flat tiles that sit close to the deck, a batten or counter-batten system is used to elevate the tile and create the required air gap. The foil goes down before the battens.

1

Install the secondary waterproofing membrane

Lay your secondary waterproofing layer on the deck first, per standard tile roofing practice.

2

Roll out RoofingFoil™ + Underlayment over the membrane

Starting at the eave, roll the foil horizontally across the deck over the secondary membrane, working up toward the ridge.

3

Fasten to the deck

Attach with plastic cap roofing nails. Staples work as a backup but cap nails are preferred for long-term hold. Since you're using battens, you will use less nails on this install than the scenario above with curved tiles.

4

Overlap each row 4–6"

Overlap each row by at least 4" (up to 6") as you work from the eave to the ridge.

Tip: More overlap = better moisture protection. Don't go under 4".
5

Install the batten system on top of the foil

Attach your battens or furring strips directly over the foil. The battens elevate the tiles and create the required ½"+ air space between the tile and the foil below.

6

Install the tiles over the battens

Proceed with your standard tile install. The foil is now correctly positioned to reflect up to 97% of radiant heat before it can pass into the structure below.

Roof layer order — top to bottom
Tiles outermost
Batten / furring strips + air space ½"+ min.
RoofingFoil™ + Underlayment
Secondary waterproofing membrane
Decking
Attic / interior innermost
RoofingFoil installed under slate tile roof

RoofingFoil™ installed under a slate tile roof with batten system creating the air gap.


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