Concrete slab over deck footings (pour at same time)

DLO33 · Mar 19, 2017 9:06 pm

In the process of sorting out the footing pads and spa foundation, however I'm a little unsure if you can lay (at the same time) a concrete slab over deck footings.

I've mocked up a quick drawing, and as you can see for the 3 left deck footings they are essentially half way under the concrete slab.

1. Can I simply put the slab formwork over the footing hole and concrete both at the same time?
2. If you do pour both at the same time, does this mean I cannot have roadbase under the slab (as it will fall into the footing holes)?
2. If you don't pour both at the same time will this make it more prone to cracking or anything like that?
3. Could I extend the slab a little further to the right so it fully covers the footing holes? Do you loose the structural intent of the footings in this case?

Deck and house plans have already been sorted, so don't really want to add a cantilever to the deck.

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DLO33 · Mar 22, 2017 6:57 pm

I've quickly mocked up some rough diagrams of what I'm trying to achieve as it seems my questions are a little unclear.

Can I pour the deck footings and spa slab at the same time (deck will not be installed yet). Slab is overlapping the deck foundations to try and get the spa as close to the deck as possible.

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I would prefer to pour the slab a little bigger which fully covers the foundations like this. Is this also viable (i.e. concrete will not crack and the footings still will achieve the engineers intent. Pour at once, or separate times?

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Any advise is much appreciated!

h.laurice.smith · Mar 22, 2017 10:02 pm

DLO33

I've quickly mocked up some rough diagrams of what I'm trying to achieve as it seems my questions are a little unclear.

Can I pour the deck footings and spa slab at the same time (deck will not be installed yet). Slab is overlapping the deck foundations to try and get the spa as close to the deck as possible.

Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅

I would prefer to pour the slab a little bigger which fully covers the foundations like this. Is this also viable (i.e. concrete will not crack and the footings still will achieve the engineers intent. Pour at once, or separate times?

Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅

Any advise is much appreciated!

Just showed my partner who is a concrete pumper. He said it can't see any dramas but it really comes down to the engineer.
Sometimes they get a bit funny with pouring footings with the slabs.

bashworth · Mar 23, 2017 11:06 am

I don't really see why you need footings and a slab.

If it were me I would

Forget the three footings holes on the left
Leave the slab where it is.
Fix the deck to the edge of the slab