Insulating porch floor

[diykate]

I have a porch that sicks out from the main building. It has a little cupboard underneath accessed externally. I am proposing to insulate the concrete floor of the porch by sticking polystyrene slabs to the ceiling of the little cupboard underneath. I am sure there are better more efficient ways but they are probably beyond my DIY skills, so hoping this will at least help somewhat. Any pitfalls to this approach? Thanks

[diykate]

Further to above, which is better- knauf space board or polystyrene slabs 60 cm thick? Area is so small that extra cost of knauf is insignificant if there are real insulation benefits. Will any of it make any difference or do I have to rethink the whole thing? Do I just use no nails adhesive to stick it up or do you have to use a special adhesive?

[welsh brickie]

there are no pitfalls with your suggestion,any insulation is a bonus