# Porch roof attached to house at Fascia.



## odd jobs (Nov 17, 2020)

What is the building code for attaching a porch roof to the roof line at the fascia/gutter?  What is the minimum desired pitch for the porch roof?


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## steveray (Nov 17, 2020)

So you are talking about hanging the new roof off of the existing overhang? Likely no bueno...


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## mark handler (Nov 17, 2020)

I Normally do not allow it without modifications 
The new roof can generate significant uplift forces from wind and gravity loads. 
How is the weight of the new roof and any live loads transferred to the supporting wall, reverse loads for wind uplift also need to be transferred and adequately tied down. 

You may need a design professional to determine if  the roof framing need to be strengthened.


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## cda (Nov 17, 2020)

It doesn't snow in Kentucky


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## classicT (Nov 17, 2020)

If it is a stick framed roof (rafters), then you will need an engineer to review the reactions as described by Mark.

If it is trusses, you will need to reach out to the truss engineer, who will most assuredly tell you you it is a flat-out no, as it can alter the tension and compression forces within the truss chords.


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## my250r11 (Nov 17, 2020)

Remove existing roof covering and decking far enough back to start your new rafters on top of the exterior wall.


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## steveray (Nov 17, 2020)

my250r11 said:


> Remove existing roof covering and decking far enough back to start your new rafters on top of the exterior wall.


That is what normally happens here....and then if the pitch changes it holds all of the ice and snow....


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## ICE (Nov 17, 2020)

Shirley it Depends

What is the overhang depth?
Rafter tails are 2x4....2x6....and how far apart?
Fascia is what 2x....1x....x4.....x6  bigger than that?
What do you plan on hanging on the fascia?  Wood porch roof?  How much wood porch roof?

If it gets engineered to hang from the fascia there will most likely be A35s from rafter tail to fascia.  Everything would have to be 2x.  If it's 2x4 rafters they can't be very long ......and there will probably be blocking required.....you'll see .... if you get it engineered.  Of course if it's a small porch roof....the engineer will cost more than a small porch roof.


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## odd jobs (Nov 17, 2020)

The proposed porch roof is to be attached to the existing roof rafters thru the fascia via a 2x6 ledger using 4" lag screws at 16" OC.  The pitch is 3/12.  The roofing material to be used is to be Ondura asphalt corrugated panels attached to 1x3 pickings that are sitting on 2x6 rafters.  The rafters are attached to the ledger and beam with joist hangers.  The over hang on the house is 18".  A 15" soffit ladder or rake will be attached on the outside of the beam.  The beam will be supported by 3-4x4 posts.  The porch dimensions are 8'5"x 16'.


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## odd jobs (Nov 17, 2020)

I meant 1x3 purlings, not pickings.  DAMN smart phones.


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## odd jobs (Nov 17, 2020)

cda said:


> It doesn't snow in Kentucky


We get our fair share of snow but it's usually in bunches and usually gone in a few days.  The saying here is, "if you don't like the weather, stick around its soon gonna change."


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## Rick18071 (Nov 18, 2020)

The IRC does not have a prescriptive design for roof slopes less than 3/12. If less than 3/12 it must be designed by an professional.
Roof pitch also is determined on what covering you are putting on it.


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## steveray (Nov 18, 2020)

Not entirely true....



Rick18071 said:


> The IRC does not have a prescriptive design for roof slopes less than 3/12. If less than 3/12 it must be designed by an professional.
> Roof pitch also is determined on what covering you are putting on it.



R802.2 Design and construction. The framing details required in Section R802 apply to roofs having a minimum slope of three units vertical in 12 units horizontal (25-percent slope) or greater.

The details don't apply, not the whole code...


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## Paul Sweet (Nov 19, 2020)

The prescriptive rafter span tables in 802.4.1 apply to all roof slopes.   The span is measured horizontally, not along the slope of the rafter.


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## classicT (Nov 19, 2020)

Paul Sweet said:


> The prescriptive rafter span tables in 802.4.1 apply to all roof slopes.   The span is measured horizontally, not along the slope of the rafter.


Correct.

As Steveray pointed out, it is only the framing details in Section 802 that do not apply to roofs with a pitch less than 3:12. Where less than 3:12, roof framing must be done similar to floor framing with traditional ridge beam and rafter framing methods (i.e. no collar ties, ceiling joists, etc.).


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## steveray (Nov 19, 2020)

And most importantly "full bearing" for the rafter ends....a 2 pitch rafter has little desire to stay on the ridge board...


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## ADAguy (Nov 19, 2020)

Does Kentuck still not require contractors to be licensed?


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## odd jobs (Nov 19, 2020)

When did they ever NOT require contractor licensing?


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## ADAguy (Nov 20, 2020)

actually back in the 80's.


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