# Forum Home Renovation Concreting  Is this slab design too-much?

## SendHelpPlease

Hi all,  I have got engineering done for a slab for a house extension. There is an existing slab in place where the extension is going, but it is not up to spec for the engineers to be happy.  They completed soil tests and classed my site as H2. They propose the following (below diagram) for a 8.8m long and approx 6m wide slab. The slab will have a single story wooden frame and truss roof over it, it will become a master suite and part of the lounge room.  
Is this pure overkill for the area and should I go back and try and get this looked at?  I have received quotes for this slab for between 14-16k, does this seem right?

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## sol381

Thats how engineers design things these days. Im doing a house raise and it calls for 150mm thick slab with bored piers down to 1800mm . way overkill.  Fist time me or my concretor had ever seen that. But not much we can do about it. they must have shares in the concrete plant.

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## METRIX

It doesn't look anything out the ordinary, considering you are on a H2 classified site, the soil type is what determines the starting point for the footing / slab design. 
Getting it looked at ?, you can ask but I don't see what they can change, it all looks to be minimum spec to me with a slightly larger mesh. 
What were you expecting it to be ?

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