Condensation in Attic / Ventilation Question

Guest User
10/23/2009
We had a new standing seam roof put on a few weeks ago, replacing asphalt shingles. We think it looks great, but we have a problem with condensation in one of the attics. This attic is directly over a wood stove. The roofer says that it can't possibly be his fault. I think he is *probably* correct, but a) I want to know if it is his fault and 2) I want to know the best way to fix it. Pictures of the part of the roof I am asking about are here: http://picasaweb.google.com/mcorner/Roof# The condensation is visible on the underside of the ridge cap and the plywood seems very damp (there is a layer of sheathing boards under most of the plywood as well). It is pretty humid up there 70% or so, even though it isn't humid here right now. Ventilation: This is a very old house (parts of it from 1790), so adding ventilation was challenging. There was a ridge vent and he replaced that with a metal ridge cap. There were 1-2" button vents in the soffits, but I know that they are clogged up with insulation. It isn't as simple as unclogging them (although I haven't done that yet), because there is a beam that almost entirely blocks the path from the soffits to the ridge. See pictures. Insulation: This attic has 5-6" inches of cellulose, which is a totally inadequate R15 (New England). I didn't really notice this until now. So the options I see (or combinations): 1) Try and make these soffit vents work. Clean them out, and possibly replace with a continuous strip. The roof is built so that the plywood/sheathing boards contact the beam, blocking the airflow. Should I shave a bit off the edge of the beam to get air going? Is there a better way to do this? 2) Add a gable vent of some kind. This is an end of the house without another end for cross-flow ventilation, but we could put square vents lower down (on each side of the chimney) and get airflow from there to the ridge vent. 3) Add a lot of insulation. My roofer suggested doing this with no ventilation. At R-15 we need more insulation anyway (he said R-60!). Pink bats or more cellulose? If we try and get the soffits working, we will need foam baffles or something to keep the insulation out of the soffits. Sorry for being long-winded, I want to get you all of the relevant information. Thanks, and I love the roof! -Mark
Todd Miller
Isaiah Industries, Inc.
10/25/2009
This is undoubtedly a ventilation and insulation issue. Increase the insulation. Maximize the intake vents ... you want to be able to bring in as much air through the soffits as your ridge vent can exhaust.
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