Go to J & W Redwood with your measurements. they will spec out all the wood and hardware you will need based on your measurements. This is an easy do-it yourself project and will cost you only for materials. If you hire someone, just double the materials cost and you will have a ballpark figure. I estimate materials at $2000. So your total cost is around $4-5K.
I used Redwood to build 3 10X12 patio covers and they came out great. I also stained instead of painted. It cost me $1,500. However, this was in 2001 and i am sure the price of wood has gone up considerably. If I had to do it over again, I would seriously consider some of the new composites like TREX. Supposedly lasts forever. with little maintainance. Porkman
