12 foot span without supports?

[betapaul]

I live in south MS so snow load is not an issue. I only have one slope that is 6X12 and will be covered with tin. I'm using 4x4 posts and 2x4 rafters with 1x4 running across. Do you guys think I need a support beam in the middle?

 

[hemet dennis]

Yes 12 ft. is to long for a 2x4.

 

[betapaul]

Even with 24" centers only holding up tin with no sheathing?

 

[hemet dennis]

If you're going from one post to another post that's 12 feet apart a 2x4 will not be straight with nothing on it it will bow.

 

[Clay Mudd]

Are the rafters running lengthwise (12 feet) or crosswise (6 feet)?

Either way., depending on the quality of the roofing, it may have enough rigidity in itself not to sag,

 

[Chemguy]

The only way I know of to accomplish a 12 foot span would be to use a truss. Or, a beam could be made by attaching three pieces togther, face to face.

 

[Ridgerunner]

I have 2x8's on end spanning 12 feet. They've held up to some pretty good winds, probably similar to what you'll see in your afternoon thunderstorms but not what you will see in a hurricane.

Will a 2x4 handle a 12 foot span? Not no how, not no way. Will they handle a 6 foot span? Probably, I'd even say yes. But I'd attach them real well to the end and middle supports so you don't get them flexing upward. Use good screws or nails long enough and nails with the ribbing so they don't work loose. Some type of connector or strap to hold them down might not be a bad idea.

I know from experience that a roof will lift off in a high wind. The people I bought from used short smooth nails. Those did not work.

 

[betapaul]

Thanks guys! What about using 2x6?

 

[rickyarthur]

I would use 2 2X6s with plywood in the center using construction adhesive and nails to make your own joists. I agre that 12' is much to long to span with 2X4s.