Frequently asked questions

Silca system is a structural paving support for elevated decks and patios. It is a grating product that screws directly to the joists of a standard timber, aluminium or steel deck structure and provides a sold, flat surface on which to lay most kinds of paving or tiles.
Supply of Silca System Grates is between $100 and $150 per square meter +gst +freight. Depending on quantity ordered and position in industry sector. Connectors, screws and adhesive are additional to the base Grate pricing. However, each project is different and we will be happy to customise a price solution specific to your project. We understand construction can be costly so will try and help where we can.
Almost all paver types can be installed over Silca System. The maximum distance any paver will ever need to span is only 50mm (over the hexagonal cell of the grate) therefore tiles do not need to be structural. We do however recommend that pavers/tiles be over 14mm thick and that the underside of the paver/tile is dead flat or consistent as to forgo any risk of rocking or cracking. Should you find any rocking in your tile, this is easily fixed with a few more dobbs of adhesive, or simply grind off any high spot with masonry grinding disk, flappy sanding disc or similar, or if a geo textile cloth is laid with a shallow sand bling layer. We do not recommend 10mm ceramic or bathroom type tiles.
Silca grates are screwed to the deck joist using x6 screws per unit (can be supplied with your order upon request.) There are pre-formed countersunk holes in the grate's edges, so location is easy. Do not over tighten your screws as this can damage the grate's structure. A firm hold on the countersunk holes is fine.
Please see our Joist Span/Paver thickness table here Alternatively this can be designed by your engineer, architect or builder particular to your requirements e.g. spa, fireplace, vehicle use etc.
Depending on your paver choice and application there are several solutions for you to choose from.
  1. Glue fix the tiles/pavers direct to the Silca grates using our recommended adhesive (can be supplied with your order upon request). Install tiles with gaps for drainage or without gaps if the deck has fall. Spot fix the adhesive around the screw areas on the grates and Lock Connectors, this provides a good key for the adhesive. Place down pavers using spacers and strings to keep straight. A 3mm spacer is a nice fine gap yet still allows water to drain. A 5mm gap is regarded as a permeable surface and level entry through thresholds. Allow adhesive to fully cure before removing spacers or walking on finished surface.
  2. Lay down a geotextile cloth on top of the grates then lay your pavers and bind by sweeping in a polymeric sand (cement based sand) or grouting. There are more flexible grouts these days so cracking has not been an issue. Even permeable grouts so water can drain through without the need for fall. This is up to your design preferences.
  3. If the pavers are heavy enough e.g. people have used 1mx1mx60mm concrete cast slabs, a simple dry but lay can suffice and will stay put under their own weight. Again, design preference as a grout line may still be required to hide deviation in paver gauge, square etc.
No. Wood and composite flooring trap water and moisture, creating an environment for mould and mildew. Wood and composite deck boards also warp and distort over a period of time, making an unacceptable surface for proper Silca Grate installation. You can remove old decking boards and still use the existing deck joists provided they meet specification and are positioned at 400mm centres. Some adjustment is not too bigger task if required.
We can supply our recommended adhesive with your order upon request. Wedi-610 A versatile single-component adhesive and sealant that suits perfectly for tile and polymer adhesion, is water-resistant and vulcanises into an elastic adhesive in the presence of humidity. It offers excellent weather and chemical resistance, is free of solvents, silicon and PCP and has low shrinkage. Available in both 310 ml cartridge and 600 ml sausage.
Yes! For quick cuts around posts, pipes or vents, use a circular saw, jig saw or reciprocating saw. For multiple straight cuts a benchy or table saw works great! Alternatively you can overhang your grates and cut them off all at once around the perimeter.
There is a wide variety of options, all up to your design preference. e.g. Timber facia, aluminium, colour steal flashing or your choice of tile to match laid vertically underneath a bullnose. using a suitable adhesive. You can find some details here: here
Silca Grates are based on the hexagonally structure of beehives and manufactured from engineered polymers into grids that are 38mm thick. Each grate can take over 5tone spanned between joists and over 68tone compression test!! Yes, you can even drive over it. Great for an elevated car port or small bridge, (substructure to be engineered accordingly)
Yes. Silca System Grates can be installed in conjunction Outdure Aluminium QwickBuild joist system or with our Rubber Joist Mounts from DeckChairSystems and ripped timber joist. Please see our Silca I-Lock Connector and rubber mounts here here
Please send us through your details and requirements here and we will be in touch same day. We distribute Silca System direct from our manufacturing facility in Auckland, NZ to save you time and money. Alternatively should you prefer to use your local building supply merchant we do this regularly and are happy to supply through them.
Silca Grates are stacked and wrapped on a standard timber pallet. (162 units per pallet, that's 30sqm) Custom shipping solutions can be arranged dependent on quantity and location. Please talk to our staff regarding your specific requirements.
Yes. Free Pick up is from our factory in East Tamaki, Auckland. NOTE: Please let us know when you plan to pick up your order and we will have it ready for you. Stock needs to be arranged and coordinated so please DO NOT just show up without our correspondence. Thank you.


Every Project is different, so please contact us for a quote.