Browse Forums Building A New House Re: Hickinbothan in freeling 9Jun 20, 2019 1:41 am Actually ours is a stiffened raft footing. (Widely used in SA due to the reactivity of the clay in much of Adelaide.) no polystyrene under our slab.
Piers are rarely used on residential homes with 1m+ deep footings common. My sister a civil and structural engineer for a big engineering company actually did the calculations from the supplied soil test rests to ensure the design from the engineers that metricon use was suitable. Material cost of our slab as designed is approx $30k plus all the labour, soil removal, overheads etc and that’s based on large commercial quantities prices. Re: Hickinbothan in freeling 10Jun 20, 2019 2:07 am Stiffened rafts are much better than waffle pods, but if 1m+ deep footings are still buried in reactive soil/clay, it will be a bit of a concern. In NSW they use piering a lot. Insider can tell you more about at which depth the soil starts to be less reactive in your area, but as far as I remember it is usually much deeper than 1 m (in some places it is 3m+). I believe that slab should be designed as almost suspended too, otherwise you may have an issues if water gets under the clay which is under your slab. Keep in mind that labour is generally 2/3rds of the cost and materials only 1/3rd or even cheaper. |