Firth launches new earthquake strength RibRaft®EQ flooring system to provide comfort to those rebuilding in
Christchurch
Firth Industries new RibRaft®EQ flooring system has been designed to comply with the seismic specifications of the
Department of Building and Housing approved flooring solutions for the Christchurch rebuild.
RibRaft®EQ system is an enhanced version of Firth original RibRaft® floor - an innovative method of concrete floor
construction that is quick and efficient to install and offers great strength and insulation benefits.
The system uses polystyrene pods, steel reinforcing rods, plastic spacers and RaftMix™ concrete. Each of the components
fits together simply which dramatically reduces the labour time and the cost of installation.
Firth’s Southern Regional Manager, Dominic Sutton says, “When it comes to creating a home that is strong, safe and warm
the floor you choose is vital.
“Firth’s original RibRaft® flooring system has proven itself over many years and performed beyond expectations during
the Christchurch Earthquakes,” he says.
“Now Firth has modified its successful formula to create an even stronger, more secure floor because we want
Christchurch residents to be able to rebuild with confidence in the foundations of their new homes in these uncertain
times,” says Sutton.
Sutton has had his own experience of just how well Firth’s RibRaft® flooring system performed during the recent
Canterbury earthquakes.
Dominic Sutton lives in Cashmere and built a granny flat five years ago for his mother in-law on the same property as
his weather board home.
The granny flat is a two story house constructed from Firth 20 series masonry blocks with a concrete mid floor and a
RibRaft® foundation.
Dominic Sutton’s home is an older weather board home, built in the late 1940s on a more traditional unreinforced
concrete foundation - this did not stand up to the second big earthquake to hit the region but the granny flat did.
“Come February 22 our house exploded and the foundations are now broken and ruptured in multiple places,” says Sutton.
“Basically the house twisted and vibrated on itself and has now come off its foundation and we have not been able to
live in it since then,” he says.
The Suttons’ home is in the white zone – which is an undecided hill zone. It is likely to require either significant
repair or a total rebuild. Amazingly the granny flat had no structural damage at all despite the fact that the two
dwellings are immediately next door to each other and would have been hit by the same the shock wave.
“There is some minor cosmetic damage - a small amount of broken gib - but my mother in law is still living there,” says
Sutton.
“The home acted like a bunker - the RibRaft® would have shaken but all the steel in it would have held everything
tight,” he says.
“As the RibRaft® system floats on top of the ground when the ground starts shaking it can largely mitigate the effect of
lateral spreading,” he says.
“It’s very strong compared to the old system the current building code is far more earthquake specific than it was in
1948.”
Firth was contacted after the first earthquake in September by research engineers who wanted feedback as to the
performance and location of existing RibRaft® floors in the Christchurch and Kaiapoi regions.
The September and February quakes have caused significant ground failure around the region - some homes have sunk by
more than 200mm. Many of the worst affected areas have now been red - zoned.
Sutton says he has spoken with many of the occupants of these homes with RibRaft® floors and they are very pleased with
their purchasing decision to pay a bit more for this type of floor.
“The Department of Building and Housing’s foundation solutions guide suggests six or so ways of building foundations to
cope with liquefiable soils.
The new RibRaft®EQ system complies with their requirements and will give those rebuilding or building their homes
confidence in their foundations,” says Sutton.
The new Regional Lounge at Christchurch airport only opened two months ago, it was installed during the earthquakes and
it also features a large RibRaft® which has been coloured and polished. The new RibRaft®EQ system is suitable for both
residential and light commercial applications.
ENDS