My brother and I added a porch roof to his house. Appox 35 by 15. We enclosed it this weekend ,and it will eventually be living space.
He will insulate ,install a air space chase between sheathing and insulation, then sheetrock the ceiling. 4/12 pitch
vented soffit
sheetrock to rafters
Can we not, vent the ledger ,and hope condensation wont be a problem? or are we just fooling ourselves, and need to figure out how to vent the ledger?
thank you
Any pix or sketch? - seems some movement of air is necessary - and I would think higher in the back- how about the old wall under the high area of the roof and vent through the attic out?
It seems to me I have seen a sketch of this in Rob Thallon's book on framing. I believe you vent this at the ledger by leaving the sheathing just shy of where it hits the ledger and then flash from the vertical wall over the porch roof so that it covers the gap in the sheathing and the ledger. Then you can screen that slot or use some corex-type venting, a la ridge vents.
mt
There are details in Thallon's book and I have details for venting in the Sunroom details as this is also an addition roof.
Another way to go that is being approved more and more often is to airseal the entire roof cavity (no vent space) with spayed foam insulation. Then you would not need a vent at either the bottom or top of the porch roof.
John,
For the spray foam option, if the space is small (e.g. 60-80 sf), would one just use the cans of expanding foam that one finds at HD or Lowes?
mt
For a small area that might be the simplest. Here are two other informative links:
http://www.alliantenergygeothermal.com/stellent2/groups/public/documents/pub/phtv_se_in_bu_000575.hcsp
http://www.fomofoam.com/
I wonder if you could use clear plastic wrap or similar - 4 mill poly- etc to close the cavity to fill. hmm