SOUND PROOF CEILING WITH EXPANDING FOAM

[Jay-Z]

I need to sound proof my bedroom ceiling from a noisey flat above, the ceiling is about 16 metres sq. I live in a Victorian conversion flat. The ceiling just has plasterboard over the joists and no insulation. I am intending to screw up a new layer of 12.5mm thick sounbloc plasterboard over the existing ceiling to block out noise. I didn't want to lower my ceiling so I wanted to avoid leaving a small gap between the two layers.

But I have heard that insulation is key to blocking out noise. I wondered if it would be a good idea before I put up my new soundbloc board, to drill small holes in the existing ceiling and spray with expanding foam to fill the void above. I saw that Wickes sell expanding foam in 300ml size cans. It states it has sound proof qualities. Is this a good idea? Will this help block out sound? Is this safe? How much coverage would I get wth a can?

Any advice would be great.

[welsh brickie]

Not a good idea it will just expand and fill the void but noise will still travel through the joists,and besides the ammount of cans you will use will be expensive.
A suspended ceiling is better so you can fill with insulation, and it will help with your heating bill and cut the noise down considerably.