Attic is finished but not insulated. Solutions?

[Jason Hatfield]

Here is a question for you experienced rehabbers.  I'm working on a deal for a split victorian with two bedrooms connected by a small hallway in the former attic space.  The problem is they drywalled the entire area but stupidly never insulated the ceiling and walls.

The drywall is in great shape so I would hate  to rip it out and have to redo it only to put fiberglass insulation in.

I could try to take it down but salvage the existing drywall and attempt to reinstall it but even if I could locate and take out all of the screws its probably more effort than it's worth.

The other option I have is slow rising spray foam.  This would only require patching the drill holes in the drywall when all is said and done but I've never used this stuff and it seems very expensive.  

Has anyone crunched the #'s on this before?  Was the cost of spray foam more expensive then the cost to rip down, fiberglass and rebuild?

This is a rental so while I want it done correctly every penny does count.

Thanks as always!

[Steve Babiak]

Did you consider blown-in insulation?  Small round hole cut at top of wall for each stud bay, and then filled with the blown-in product. Once completed, small parches for the holes and then paint. 

Make sure heat and electric are in place first too.