Frequently asked questions
Silca System interlocking, structural deck grates are specifically designed for the support of heavy finished surface materials over elevated deck structure.
Manufactured in New Zealand from 100% recycled materials, our grates offer a robust, durable solution for installing tiles or pavers at any elevation.
Silca Grates connect together and are securely fastened directly to timber or aluminium deck joists. This provides a solid, flat, permeable surface to install various paving materials such as tiles, natural stone, heavy pavers, artificial turf or porcelain.
Silca System enables a free draining finished surface and air circulation beneath, preventing moisture buildup in the substructure and ensuring the longevity of the decking element. Suitable for standard elevated decks or those floating over membrane,
Compliance to B1/VM1 and B2 of AS/NZS1170.1. and E2/AS1 Permeable surface – level entry through threshold. Silca System is an environment-friendly patio solution for both residential and commercial applications.
Supply of Silca System is between $100 and $200 per square meter +gst +freight. Depending on quantity, products ordered and position in industry sector.
Grates, Connectors, screws for timber or aluminium joist and tile adhesive can all be supplied.
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 a minimum of 14mm thick and that the underside of the paver/tile is dead flat or consistent enough to mitigate any risk of rocking.
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 Design Statement - Joist Span/Paver thickness table here
These are designed to NZS3604 and complies with Clause B1/VM1 of AS/NZS1170.1. NZBC.
Alternatively, your substructure can be designed by your engineer, architect or builder specific to your site requirements e.g. spa, fireplace, vehicle use etc.
Depending on your paver choice and application there are several solutions for you to choose from.
- 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 head areas on the grates, on the Lock Connectors, or where each grates butts up to the next. These areas provide 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 required by E2/AS1 as a permeable surface for level entry through thresholds. Allow adhesive to fully cure before removing spacers or walking on finished surface.
- 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.
- If the pavers are heavy enough e.g. people have used 1mx1mx60mm granite slabs, a simple dry 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, squareness etc.
No. Wood and composite floorings 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 are in suitable condition, 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 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 load 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 more information in our resources here here
Please send us through your details and requirements here and we will be in touch pronto.
We distribute Silca System direct from our factory 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 picked and packed and coordinated so please DO NOT just show up without our correspondence. Thank you.
LOOKING TO PURCHASE SILCA SYSTEM FOR YOUR NEXT DECK?
Every Project is different, so please contact us for a quote.