Soffit Vents / Ridge Vent Needed Here?

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Old 01-15-20, 06:29 AM
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Soffit Vents / Ridge Vent Needed Here?

I am finishing up my 14x14 sunroom and have already installed the soffits, and the roof has been shingled. The roof is 4.5 pitch with a ridge beam (LVL), 2x6 rafters. It's still bare on the inside, I haven't insulated it yet. It dawned on me however, that I may need soffit vents and those styrofoam trays going up the roof to a ridge vent. Do I need that, since the inside of the roof will be covered? What could happen if I don't do any of that, will moisture collect on the inside of the roof?

Thanks for the input.

Live in Southern NH. Can someone explain how to add location to the area there where it shows how many posts you made? I have the info in my profile but the state isn't showing up.
 

Last edited by slade8200; 01-15-20 at 06:47 AM.
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Old 01-15-20, 07:00 AM
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What are you insulating it with?

Closed cell spray foam does not require venting.

Fiberglass and rock wool do require venting.
Also advisable for open cell spray foam but not as critical as the above two.
 
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Old 01-15-20, 08:25 AM
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Using regular fiberglass. So venting is all 3 things? Soffit vents, styrofoam channels, and ridge vent?
 
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Old 01-15-20, 08:54 AM
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Yes all three.

Had to add this to get to 25 characters
 
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Old 01-15-20, 09:09 AM
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FYI I used to live in West Deering NH, near Hillsboro.
To late know but I would have used 2 X 10's instead of 2 X 6's so there would be room for more insulation.
If there's going to be a flat ceiling you could add venting on the sides, but you will need baffles and soffit venting.
My dad had one built the same way yours is and it was a nightmare.
The pitch was so low and with the heat transfer a layer of ice would form and we had to get up there and shovel it off after every storm because the snow never ran off the roof.
 
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Old 01-15-20, 09:32 AM
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and the roof has been shingled.
Well, that's going to have to be partial torn up!
 
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Old 01-15-20, 10:21 AM
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Ok. Just so I can understand, what happens when you don't have any venting? Is the problem worse in the winter or summer?
 
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Old 01-15-20, 10:41 AM
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If you do not have venting then heat and moisture can build up under the roof sheeting.
So you get things like ice dams as joecation said.
In winter you can get moisture condensing which can rot the wood and cause mold.
In summer the heat can build up so AC costs more to run.
 
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Old 01-24-20, 06:10 AM
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Just curious, why don't you have to vent exterior walls? Wouldn't the same things happen as a roof?
 
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Old 01-24-20, 06:28 AM
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It does happen in the walls but to a far lesser extent.
Also you have sealed the outside of the roof with shingles but the walls are more porous so heat and moisture can escape.

In the summer on a hot day feel how hot the roof is and then feel the exterior walls and you will see the temperature difference, It is not only the difference in color and material but also the angle of the suns rays.

In winter the moist warm air rises in the house and can enter the up into the ceiling so it needs a way to escape.
 
 

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