This is really not a good question to address to a Realtor..... It would be best for you, to have several contractors stop by, tell them what you are looking to build as far as your room addition is concerned and make sure you give
each one the very same information and ask them for an estimate, remember that usually once they start, and you things happening you may make changes and they will cost you extra....
Building materials, number of windows, heat and a/c, rood type etc. all will make a difference in cost.....
Just have them stop by they should give you a free estimate.... Really the best way to go about it.....
Your Chicago and Northern Illinois Expert
I have been told for builders grade construction it's about $200-$250 a foot. Best bet is to get some estimates.
The Carrbba Group
Keller Williams Hollywood Hills