Room additions can be a great solution for some. The most important aspect is protecting your investment for the long term, which means working with a licensed professional and making sure the addition is permited and done correctly. Your design and wants list will determine the cost. If the addition is permitted and done well, you'll be able to recaptur e a higher level of your return and be able to include the additional square footage in calculating future value if and when you decide to ultimately sell. your home.