Has anyone tried the polystyrene cubes as fill in concrete slabs?

Question

We are going to be laying a 300mm high slab, I've heard about polystyrene infill cubes instead of using compressed infill. Are they any good?

Answer 1

I am assuming that you are talking about using a premanufactured system. That will work well if it is installed correctly. If you are talking about simply adding pieces of polystyrene to the concrete that won't work they will simply float on top of the concrete and it will be a mess.

Answer 2

Have seen the method used  to "thicken" a slab wihout bringing in a lot of fill.

Basically you will end up w/ a "waffle" slab.

Might get some advice as to the size / thickness  of the  foam fillers &  the spacing  between reqd to get the proper web thickness.

The work I saw done had rebar & steel mesh in the pour.

Found the reason for doing it was speed  ( for the pour), less concrete  had to be brought in  since the work area was surrounded by occupied , finished space .

Just a thought , but for an approx 12" slab just using fill &  concrete might be less work considering the prep done for a waffle pour.

Best regards

Answer 3

Yes they are fantastic, in the Southern Hemisphere they are call "Waffle Pods" and are used in the application you mentioned for floor slabs.

Saves a lot of compacting and you can buy the materials and sculpture them to suit your application. To cut them you can get a fancy hot wire device but if you don't have a lot to do just use a hand saw with a mask as the foam tends to fly about when it is fine.

Have fun

Answer 4

Yes. They are very good especially for their insulating qualities. You still have to pour concrete in between them. You basically lay the "pods"in a grid, not butting up to each other. The concrete must be on a solid base. From experience you are probably better to use compacted fill.

Answer 5

It's called ICF (insulated concrete forms).The system is very good,to those that take the time to understand.It has a host of benefits to large to mention.

Good Luck

Answer 6

I will look forward to other answers.  I have a Styrofoam basement (cement between permanent Styrofoam forms for walls).  And am in construction so always interested in new products and innovative ideas.