Outdoor living spaces can increase your home's appeal at a lower cost than an additional room

Here is a article we came across from US News about the value of adding outdoor living spaces

Adding a Deck: A Cost-Effective Way to Protect Your Home’s Value

http://www.usnews.com/money/personal-finance/real-estate/articles/2008/11/21/adding-a-deck-a-cost-effective-way-to-protect-your-homes-value.html