'Raise the roof' is usually about noise. Example:
'Hello children, my name's Coco.'
[quietly] 'Hello Coco'.
[mimes deafness] Did I hear a noise then? Let's Try again. Hello children.'
[louder] 'Hello Coco.'
[mimes mild satisfaction] 'Not bad. But I'm sure you can do better than that. Come on - really raise the roof....'
As noise tends to go with enjoyment/interest/activity it may, in some dialects, refer to something other than noise; not in my experience though.
- For Teachers