Cutting through concrete with a hole saw?

[damanpunk]

I've got a EcoLED downlight to be installed above my front door which will replace the 20+ year old UFO look a like that's currently there. The 'roof' of the porch where the light will go into appears to be chipboard that's had a 2-3mm skim of cement on it.

I need to drill an 86mm hole for fitting it which I can get a hole saw in but not a diamond core. With the actual amount of concrete being so thin do you think a hole saw would get through it?

 

[catlad]

It should go through but it will dull your hole saw.

 

[damanpunk]

It should go through but it will dull your hole saw.

Superb, I ordered two earlier on the off chance it may work