# Forum Home Renovation Concreting  House slab question

## buts

Hello,
Could someone help me. We just moved to a new house and I got the plans from the land office. According to their plans we should have a waffle slab with 220mm polystyrene former and 100mm of concrete above. However, the floor feels quite cold and changes its temperature quickly from day to night (I am in Canberra). I thought that the waffle slab shouldn't loose the heat that fast. Is there any way to check that they have done a waffle slab and not just a suspended slab ? They built it very quickly, I came one day and could see only sewage pipes done and next weekend when I checked the slab was finished.

----------


## cherub65

in sydney you would of had an inspection from either local council or private certifier for the footing/slab stage (waffles would have been visible) check out their paper work 
I think waffles are banned in garage construction up here, (some guy got crushed by his 4wd while it was up on jacks, not enough coverage over waffle). Please correct me if im wrong

----------


## Cementer

I am 100% positive you have a waffle pod slab. Why? It is the quickest, easiest way to prepare slabs these days. Suspended slab or conventional (dirt underneath), would have been more cost to the concretor, builder and you would have been told so and charged for it. A waffle pod slab takes three days to complete after plumbing has been done. day 1 form boards and piers, day 2 waffle pods and steel. day 3 pour and strip formboards. sometimes if the slab isn't big, it can be formed, podded and steeled in one day with the second poured and stripped. 
the thickness of a waffle slab is 86mm thick as well and not 100mm. Why, because there is so much more beams in a waffle than conventional.
The reason waffles were introduced to the industry was to simplify and accuratley execute slabs on level ground without too many variances. Easier and more accurate to price, quicker on site installation and less work to complete.
No waffles aren't banned in garages. If the slab is waffle then so is the garage mostly. 
That car falling through the slab is a wifes tale. I've heard different versions of the same story for 15 yrs in different towns it happened with no record or proof of it happening. 
Not too sure about the heating side of it though. Never heard of waffles being used for heating purposes.

----------


## cherub65

would you use waffles in garage construction?

----------


## buts

Thanks for detailed explanations, Cementer.
On the maps we have a waffle slab under the garage too.
I've looked for specifications of a waffle slab and found that they are normally  85 mm thick. However, here is the extract from the plan and it shows 100mm. I am wondering what's the 500 mm layer ?

----------


## Cementer

> would you use waffles in garage construction?

  I would but i would also put down a plate before using a car jack as well. :Wink 1:

----------


## Cementer

> Thanks for detailed explanations, Cementer.
> On the maps we have a waffle slab under the garage too.
> I've looked for specifications of a waffle slab and found that they are normally 85 mm thick. However, here is the extract from the plan and it shows 100mm. I am wondering what's the 500 mm layer ?

   The 500 mm layer is a footing of some sort or a pier. can't tell too much from the exract provided but it is mass concrete of some sort and bearing some type of load, it has steel in it. Notice the z bar tying the mass footing to the slab. At least it's keyed together. sorry, can't help with that one.

----------

