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We're just starting to build and we have had the builder asking us a few questions about the slab height.
It was drawn on the plans at 410mm as that was what we were told was standard for a waffle pod slab (by the engineer). The builder rang us a few days ago and asked if there was a reason it was 410mm and not 370mm as with the lower height there didnt need to be a step up from the garage into the house. He wanted to know if we we're happy for it to be done at 370mm.
Now we don't really care about the height, council's minimum slab height here is 100mm so there is no issue wih council but I just want to know what is normal for a waffle pod slab on HD soil? I have tried ot find it on the internet but cant find anything to help me out so if there is someone on here that can help that would be great.
So I'm after some info so we can make the right decision.
Thanx in advance
That is a bit confusing
Slab height is normally the height the slab sits from a given datum.
( an RL point ) a slab thickness is the thickness of the slab but doesn't refer to the height in any way.
Contour lines on the site plan will indicate the road height, slab height and other features on the site.
They look like this 10.0 for example only. ...there will be a series of numbers indicating relative heights.
The slab will have a 0 point and the rebate will/may have -1c (minus 1 course or -2c) referring to the first brick course and the relative slab height.
410 and 370 may be the thickness of the waffles and slab thickness combined but the builder should not be asking you any of this. 40 mm is not a brick height a brick is 86 mm and is the normal stepdown( actually the minimum stepdown)
All to confusing don't you think?
Onc
Totally confusing.
Slab height from ground on the plans from the moron who drew them up (we dont have much faith in her) in the sectional plan is specified as 400mm, which makes even less sense to me now. Someone told me that for a waffle pod slab the height from the ground was 410mm.
On the engineers plan, I can't find any mention of height about ground but in the slab notes it says the "slab is to be 85mm thick ribbed raft slab etc". Then when I look at the typical details drawing of the slab cross sections it looks to me like the minimum from the ground to top of slab is 385mm (with 85mm being the slab thickness). With the garage step details they have a step down from the main slab to the garage of 172mm?
We don't have asite plan with contour lines but the area is pretty well flat, does that make anymore sense? If it confused you no wonder it has confused us. Basically the builder wanted to know if there was a reason for the slab being 410mm or if he could do it at 370mm.
172mm is 86mm * 2. Two brick courses? It still doesn't make sense why 40mm would mean there would be no step down.
I would be telling the builder to speak to the engineer who designed the slab, they design them in a particular way to suit the site for a reason, you may even like to talk to the engineer yourself just to make sure it is ok for the site and to put yourself at ease.
Most plans have the engineer name listed on them. I have spoken to ours and they were very helpful and explained our queries.
Hmmm just as I thought a 2 c rebate to further confuse things.
Well I emailed the engineer (we had arranged him in the first place so I had all his details) he said the 410mm is the standard for G town, we are in a village outside the town so different council and he had no issue with the 370mm. The only thing he said was to check with council that it was ok - I know that the council min here is 100mm.
So I guess since there is no issue from an engineering point of view then really having the slab height at 370 rather than 410 is going to save us some money in concreting
and the house will be a little lower.
Weird I'm still confused.
Waffle pods come in different heights, ours were 225mm plus 85mm concrete cover gives 310mm. Height of waffle pod is usually determined by soil type as this determined the height/depth of the beams between and around the pods that create strenght level required in the slab. Your drafter may not of sourced accruate information on the slab. Check
http://www.slabworks.com.au/Waffle_Pods.php Brick setdowns are in the edge beam of the slab and have no bearing on the thickness of the waffle pods. In Victoris you are not permitted to have the garage at the same level as the house slab and the difference in height is usually 1 brick down. This was introduced to limit flodding from garages into houses.
We have just put in a waffle pod slab for the house on "P" Class soil (the worst kind!) I was told that because of our of ground classification we required a bigger Waffle Pod than normal
The finished slab height was 410mm consisting of
Base
150mm FCR (Fine Crushed Rock)
50mm Sand
Slab
300mm Waffle Pod
110mm Concrete on top
our Garage slab height was 335mm
Base
150mm FCR (Fine Crushed Rock)
50mm Sand
Slab
225mm Waffle Pod
110mm Concrete on top
I hope that helps
a 150mm footing for brick work and then 257mm (3 courses) to top of slab. 407mm
its purely to work courses from floor height to windows and eves. and can be worked easily around if its put in at 385 instead.
a 22mm x 300mm footing would be dug around the edge board.
I dont understand where your getting the 370mm measurement. 385, or 400mm would be minimums for 300mm waffle pods.
Hi There,
I am building with Simonds, and Intrax do the engineering designs for slab
I asked to raise finished floor level of porch 150mm as neighbour potrch
They came up with a design of putting double waffle pod, instead of adding thickness to concrete
so the concrete is now 85mm, the total slab thickness is 535mm means that void form height is 450mm
I don't know if anyone heard about double waffle pod, because I didn't find anything on web