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Tiling over an existing deck: porcelain on the Silca System
A rotting deck doesn't always mean a rotten frame. At Titirangi the boards had had their day, but the structure underneath was sound, so we kept it and laid porcelain tiles over it using the Silca System. It's one of the smallest jobs we've done, and one of the most detailed.
The job at a glance
Where: a deck at the back of the house, 2 m above a steep bush slope, with views to the Auckland harbour.
Before: an old rotting pine deck on a sound frame.
After: 600 × 600 porcelain tiles on the Silca System.
Time: 2 weeks on site.
Is the frame worth keeping?
That question comes first. Kevin inspected the substructure properly: no movement, no rot, good fixings, good framing sizes, and no rot on the posts. It needed only some blocking to strengthen it. The clients also had a builder assess the frame before anything went down. That inspection is the reason the structure stayed.
The clients did a lot themselves: the demolition, the frame strengthening and the prep, and they looked after the spa installation. The spa is 2 m by 2 m and weighs about 1.5 to 2 tonnes filled, so Kevin advised extra posts and framing underneath it, which the clients installed. Our part was the professional installation of the Silca System and the tiles, which involves heavy handling and precise work.
How the Silca System works
Silca is a New Zealand-made system of grates, connectors and stainless screw fixings, made from 100% recycled material, that sits on timber or aluminium joists. Tiles or pavers are spot-bonded to the grates with a high-flex adhesive. Silca states compliance with B1/VM1 and B2 of AS/NZS 1170.1, and E2/AS1 as a permeable surface, which means a tiled deck can meet the door sill at level entry, without a step.
At Titirangi we screwed 400 × 400 Silca grates to the existing joists with stainless screws, leaving 3 mm gaps for drainage, and glued the 600 × 600 structural porcelain tiles on. The tiles were supplied by the clients. No consent was needed on this job; whether yours needs one is settled before we quote.
Silca System also referred this job to us. The clients' review says as much: "We were recommended to use Franc Landscapes."
The hard part: a triangle
The deck is roughly triangular, so most of the border needed custom cuts, and every one was different. The hardest was the corner of the triangle, where several lines had to meet in one complex shape. Access was only through the garage, so every tile and grate came in that way.
2 weeks on site
What actually decides it
The frame. Tiles are heavier and far less forgiving than boards. The frame has to be sound and stiff, checked by someone who knows what to look for before anything goes on.
The load. A spa, planters or a crowd all add weight. At Titirangi the extra posts and framing under the spa came first.
Drainage. The 3 mm gaps and the permeable system let water through instead of across the surface.
The shape. A rectangle is quick. A triangle with a complex corner is cut tile by tile.
Where we fit
We install the Silca System and tile over it, on existing decks where the frame checks out and on new frames we build ourselves. If you're not sure your frame is worth keeping, that's the first thing we look at. See also what holds a deck up.