Building a screened in porch

I have a 12x12 above ground deck off the back of my house. I want to put a screened in porch there. How feasible is it to knock off the handrails and build a screened in porch in it's place? I would anchor a 2x6 horizonally to the house and build the roof off of it. The existing porch is supported by 4x4s around the bottom (corners and in the middle of the sides) but nothing in the center. My idea is to tear off the hand rails, and then build walls (using 2x4s) and mounting them to the existing floor.

 

Get rid of the 4x4' toothpicks and replace with PT 6x6's. Three across the front and one on each side @ 6 ft.

 

Funny, I got a screened in porch I want to make into another room.

 

If I was building it from scratch that's what I would do. Just wondering if the 7 existing 4x4's would be enough to support the three walls and the roof

 

Is there a roof already? If not, you might want to think about how it will look with the rest of the house. A screen porch tacked onto an existing deck can look really ugly if the proportions aren't right. Google screen porch and you'll find a lot of links from how-to websites. It's not as easy as throwing up a few 2x4s. Just my honest opinion.

 

Are they in the ground? below frost level? btw, a 2x6 nailed to the wall will never support the roof.

 

NO

 

MY screened porch is only 8' x 12' with a pre-existing roof attached to the house. There are 8 - 6x6 supports buried in 36" of concrete with 2x10 joists and a 2x12 lagbolted to the wall.