Let me preface by apologizing for answer your question with a question, but many considerations would need to be taken into account before even guesstimating the cost of such an improvement.
1. I am assuming this will be an attached as opposed to detached garage? This would have some bearing on the price.
2. Will a permit need to be pulled? Surely the HOA would only approve such an addition only after obtaining the appropriate permit by the governing city.
3. Are located on any incline?
4. Have you verified you will not be encroaching on other property or a utility easement?
The last question I would have to ask is are you adding the garage solely for convienence or are you factoring in the cost as compared to the value it would add to the home if resold? The one thing I can tell you with certainty is you did post your question in the correct forum considering a Realtor has to take into account any features that make your home unique in order to determine the fair market value of the home.
A few other extremely important considerations to take into account are the details of your specific property. What may cost $20,000 to build on a house built in 1999 on street B may be nothing close to what you pay for your home built in 2005, that is 6 miles down the road on street X.
The best way to get this question answered is to first entrust the services of a qualified roofer or roofing company to give you a quote for replacement. Next, I would suggest you use a Realtorâ€™s expertise and asking for a Comparable Market Analysis (CMA) that can assist you in getting the most comprehensive detail of the value of homes recently sold in your area. If there is someone in your subdivision that may have done such an improvement, you should start there as that would be the greatest resource you have.
I apologize once again for not answering the question, but I like to ensure that I donâ€™t just throw a number at someone before getting all the specifics.
Prudential Ultima Real Estate / R. K. Regan Team