# add new shed roof to existing roof



## tinner666 (Mar 14, 2005)

For a 20' clear span, you'll need an engineer to spec the correct size steel beam AND the correct specs for the two corner footings. That'll be a large point load on each corner. Possibly 6' of concrete, 2' wide, or more. ( Just gessing there)


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## charring6 (Jul 1, 2011)

*new roof addition to existing roof*

Thanks for your reply.
I apologize for not being more exact on what I was thinking about going.
I was going to put 4x4 posts around the front and sides of the shed roof say every 4 feet to support the rest of the roof. I was concerned that being I would have no supports in the center of the span if that would be a problem? 
Thank you,
Chuck


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## tinner666 (Mar 14, 2005)

Without knowing where you are from and if snow load is an issue, 2x6 can span 20'. Me, I'd prefer 2x8's and you really should mount doubled 2x10's on top of the posts, and set the rafters on top of that. 

You might want to take this to carpentry/framing to get more specs.


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## charring6 (Jul 1, 2011)

*adding a new shed roof*

Thank you very much. 
Fortunately I am in Atlanta so we do not get a lot of snow here. I was thinking about using the rolled rubber roofing. What do you think? If I used rolled rubber do I have to put felt paper under it?


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## tinner666 (Mar 14, 2005)

You'll have to explain 'rolled rubber roofing'.

EPDM doesn't get felt.
SBS has anailable base sheet and an inter-ply for adding layers, then it has a cap sheet.
TPO need to be welded.
APP needs to be torched down.
I'm not even familiar with PVC.

You can call my 232 number if you want. I'll be around for a short while.


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