Or any other proceedures involved?

I think need to apply, but anyway, isn't ur contractor / ID going to help u? Hacking, Waterproofing etc..

Yes if there is hacking work.

Yes if there is hacking work.

yes your contractor needs to apply permit

Yes you need to apply permit for hacking.

Just to clarify.

If HDB toilet, we can only engage HDB certified/Registered contractor/renovator to do hacking and tiling work?

Just to clarify.

If HDB toilet, we can only engage HDB certified/Registered contractor/renovator to do hacking and tiling work?

You can engage any firms contractor so long they can apply permit will be fine.