When air currents pass over a flat surface they create pockets of low air pressure, and because the air pressure underneath the surface is higher, the surface is pushed upwards towards the lower pressure area. This is the principle behind aircraft wings.
On a roof deck, where the deck surface is loose-laid into a supporting frame, this can result in the surface lifting from the frame and becoming unstable or damaged. In more extreme conditions, the surface components can cause damage to surrounding structures and even injury to persons.
How Raaft are improving wind uplift resistance
Uplift resistant porcelain decking and tiles
Our porcelain decking and tile products are all characterised by design flair and premium quality porcelain manufacturing. Porcelain is a highly durable anti-slip surface resistant to scratching, staining and frost damage. As a Class A1 fire rated product it also meets the UK’s Building (Amendment) Regulations 2018
Farrino Porcelain Decking offers five stunning woodgrain patterns and a long plank format that evokes the beauty of timber decking.
Atria + wind-uplift tiles is an innovation based on our popular Atria Porcelain Tiles, available in a fine selection of highly authentic wood, stone, concrete, and terrazo effect finishes and a range of sizes to create uniform or random patterns.
Farrino and Atria + tiles both feature a groove cut unobtrusively into the edge of the porcelain. Used in combination with our Raaft Terrace System, our design-protected stainless steel or Nylon 12 RP anti-uplift clips fit unobtrusively into this groove and will prevent uplift at typical UK windspeeds.
Following the principles of BS 14437:2004, the tests were conducted by independent testers BRE Group on both types of clip, fixing 600 x 600 mm, 20 mm thick Atria + Porcelain Tiles, with two clips per tile attaching them to the Raaft Aluminium Joists. Tests were also carried out on the Pedestal Joist Connectors.
Testing applied an uplift pressure of 4536N/m2 and as the products were tested to destruction, no partial safety factors were used.
The results were as follows:
Using stainless steel clips, the characteristic wind uplift resistance per clip was 738.1N
Using nylon clips, the characteristic wind uplift resistance per clip was 51.6N
By also fixing the tile with Formoa 017FE hybrid polymer adhesive the indicative wind uplift resistance per clip was 2943N
The pedestal joist connector returned a wind uplift resistance of 71.0N
The clip and groove wind uplift resistance system is also featured on our Terrafina composite wood-polymer decking, which is a durable, attractive, Class B fire-rated alternative to traditional timber decking.