The recommendations focus on foundation and floor elements but also cover common areas of 'above the floor' damage such as chimneys. For a copy click here

The guideline provides suggested floor solutions where severe liquefaction can occur. One of the solutions provided is a variant of the RibRaft system. "Foundations in liquefiable areas require a specifically designed solution," says Dene Cook, Technical Manager for Firth Industries. "Cost analysis has demonstrated that a solution using RibRaft components is the most cost effective option of obtaining extra protection against the damaging effects of liquefaction."

The Firth RibRaft floor system is a tried and true system that is supported by considerable technical information.  Dene explains, "there were a number of RibRaft floor systems that were subjected to the Canterbury quakes and they performed very well. The RibRaft system has attributes that make the floor considerably stiffer than a standard floor. The stiffness means that when ground movement occurs a RibRaft floor is less likely to sag (dip in the middle) or hog (hump in the middle) than a conventional concrete floor slab.  Ground movements may be caused by moisture changes in the foundation soils or at the severe end of the scale by earthquakes.  I would strongly recommend that if you are looking at a new floor slab you explore the Firth RibRaft solution."

For more information on RibRaft flooring systems, click here or contact us on info@firth.co.nz or 0800 800 576.