Thin ceramic or porcelain tiles are not recommended over SpanTrak fiberglass grating. When dry-laid over a rigid surface, thinner formats lack the structural strength to handle live loads and minor movement without cracking or breakage over time.

Archatrak 3/4″ thick porcelain pavers are a different story. The added thickness resists impact damage and breakage, making them well suited to elevated rooftop deck installations.

For 8″ x 8″ or 8″ x 12″ porcelain cobblestones, a 1/8″ recycled rubber underlayment placed over the grating provides sound deadening and separation, commonly available in 4′ x 50′ rolls. Use tile spacers to keep cobblestones consistently spaced and aligned. Joints are normally left open but can be filled with polymeric sand if preferred. Where sound deadening is not a concern, a geotextile mat is a suitable alternative.

Large-format 2cm porcelain pavers are typically installed directly on Archatrak Premier or NM adjustable height pedestals for standard rooftop deck construction. For decks subject to high commercial traffic or where pedestal heights exceed 4″, fiberglass grating panels or steel plates are recommended as a continuous support base.

When porcelain pavers or planks are installed over SpanTrak FRP panels, we recommend placing rubber pads between the pavers and the grating surface. These pads slightly elevate the pavers off the fiberglass panel, reduce noise transmission, and include integrated spacer tabs to maintain consistent joint spacing.

Natural stone used on elevated decks must be gauged to a consistent thickness. Because there is no ability to adjust for variations in individual unit thickness over a continuous FRP grating surface, uneven stone creates a real tripping hazard.

A 1/8″ recycled rubber underlayment is recommended between the fiberglass panels and the stone pavers. This helps reduce noise transmission, limit movement, and still allows moisture to drain freely. 

Recycled rubber underlayment is commonly available in 4′ x 50′ rolls.

Joints are normally left open, though they can be filled with sand when a suitable underlayment is in place. For softer stones such as sandstone or travertine, use a thicker gauge stone of at least 1 1/4″.

Where natural stone is sized by splitting rather than precision cutting, thickness can vary significantly. In these cases, a sand bedding layer is recommended to achieve a more consistently level finished surface over the elevated deck assembly.

A containment barrier should first be installed around the deck perimeter to retain the bedding material. Two layers of geotextile fabric are then placed over the fiberglass grating in an alternating pattern, followed by a 1/4″ to 1/2″ layer of evenly distributed sand. As the pavers are set, lightly tamp each one to bed them into the sand and align with adjacent units. Spacers should be used to maintain consistent joint widths.

Once all pavers are laid, brush polymeric sand into the joints and wet down as specified by the manufacturer.