Is concrete air tight?

Question

Is a slab of concrete 6-10 inches thick effectively airtight?

Answer 1

no, nor water tight.

During a hurricane, water can be driven right through concrete.

Answer 2

If it is not water tight it cannot be air tight.

Answer 3

all slabs get hairline cracks in them and that ruins any chance of being airtight

Answer 4

Concrete is more like a hard sponge. Water and gas can come up through the slab and liquids can stain it. We have sealed many warehouses to stop stains and dusting.

Answer 5

It depends on your definition of effectively.  If you are talking about whether you will be able to breathe through it the answer is no.  Also a body hidden within that will probably be effectively sealed from air.

But It is less airtight then encasing the same body in a plastic mould.