Jeanne, you might not like my answer but I do not think it is a good idea. 3 bedroom sharing one bath is a NO NO. It will be hard to sell with this layout. Most buyers want a separate master bath room and not share it.... more
You will need to contact a builder and find out what CONSTRUCTION COSTS are. We Realtors can only tell you what the solds are in your neighborhood which would give you sold cost per square foot. You will want to keep that figure in mind because you don't want to overbuild for your neighborhood because you might not be able to recoup your money. If you live in a neighborhood of 2 bedroom 1 bath homes and you add another bedroom then that would help you sell your home but it doesn't mean that you will get your money back out of it. Overall "comps" for a neighborhood will determine what you can get for your house. Find out the cost to construct the basic shell and see where you are at with price per square foot THEN figure out what level of interior finishes will make it come out to be the right price per square foot sold (in the ballpark) for your neighborhood. Many times, people get carried away with luxurious finishes and they just won't be able to recoup their money when they sell.
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