Ceiling venting

tvanharp · 11-23-2012, 10:48 AM

We are remodeling a room that has a dormer. There is no attic space since the ceiling matches the roof. I don't know the term for that. Vaulted, cathedral...
anyway the person that built it put in proper vents from the soffit up towards the peak. now the soffit is only vented on one side of the dormer, there is no roof or ridge vent. The part that has me confused is the fact that there is no airspace anywhere, it's completely filed with bat insulation. Furthermore, there was what appeared to be mold but only under the styrafoam proper vents where that little bit of airspace was.
I plan to seal up the soffit completely airtight, repack with insulation so the entire space is filled, there will be no airspace at all, cover with a ploy moisture barrier and drywall.
Does that sound correct?

joecaption · 11-23-2012, 12:35 PM

Nope, that's going to add to the trapped moisture and super heat the shingles from the bottom side.
Your post is confusing to me, you keep saying they added the vents but then say there all blocked.
Got a picture so we can see what your talking about?

joecaption · 11-23-2012, 12:36 PM

That style roof really needed a ridge vent. Any other style will not vent all the bays, just the one the vent is directly over.

tvanharp · 11-24-2012, 11:56 AM

Sorry it's confusing, hard to explain. The soffit venting is marginal and only happening because the facia boards have some gaps there are no actual installed vents. And yes the proper vents do nothing they are just adding air gaps under the sheeting. They have all been removed and thrown away. I am referring to air baffles (proper vent). Not proper as in the correct way.

Again I want to stress that between the drywall and roof sheeting there will not be any space that is not full of insulation.
Camera on my phone does not work, I'll see if I can upload from the other camera.

pictures have been attached.

**Gary in WA** · 11-24-2012, 09:46 PM

Where are you located?

You need an unvented roof system: http://www.buildingscience.com/docum...r-all-climates More on the R-value required after location...

Not to mention the single top plate without rafters directly over at walls, gable-end ridge support beam too small, wrong ridge hangers for solid wood, and a few blades missing on the fan...

Gary

joecaption · 11-25-2012, 09:29 AM

Also no birds mouth, no cross ties.
Is this a house or a DIY shed?
One other way to do this would be to add shims to the rafters that are equal to the depth that ridge beam sticks out past the rafters.
That way there would be room for the baffles and insulation with out compressing it, and hold make it far easyer to sheetrock.
The way it is now your going to have an issue with that ridge beam when sheetrocking.

If your in an area where you get snow or hurricanes I would be very afraid of that whole roof coming down.
Looks like no permit was pulled on that one or the man had a white cane and guide dog when inspecting it.

hand drive · 11-25-2012, 10:25 AM

As Joe mentioned, fur down the rafters with a 2x4 and I would add 2x collar ties butted up to the ridge and nailed really good to the rafters. Next,pull the ridge shingle caps and cut in a slot along the ridge for a ridge vent and then add baffles to the underside of the roof sheathing and vents to the soofit for direct ventilation of the rafters bays. Last, insulate and drywall and I would also add studs under the rafters where the rafters land on the wall because of the lack of double top wall plate and also address the issue with the ridge beam bearing on narrow width headers on the outer walls where the ridge beam lands.

tvanharp · 11-25-2012, 12:16 PM

We are in north idaho. The previous owner added this dormer and another just like it on the other side of the house.
No permits required in Bonner county.

You should see the electrical work this jack--- did.

tvanharp · 11-25-2012, 07:51 PM

I looked into the spray foam air seal. Thats going be the direction I take.
As for the construction flaws I'll add studs under the rafters and maybe cut a wedge shaped piece for under the rafters to give them the bird mouth. I'm going to add cross ties to flatten the peak but only 1 1/2" down. The gable end header holding the bean is made of 3 2x6 with 2 1/2" plywood spacers. I may add jack studs along the window to shorten the span. That should all help. don't have the funds to completely rebuild the dormers.
Oh and add a few blades to that fan.

**Gary in WA** · 11-25-2012, 08:18 PM

Sometimes minimum code is not enough; http://news.google.com/newspapers?ni...g=6748,2545061 Check the spans with your local AHJ, to be safe.

Gary

hand drive · 11-25-2012, 08:42 PM

Quote:

Originally Posted by tvanharp

I looked into the spray foam air seal. Thats going be the direction I take.
As for the construction flaws I'll add studs under the rafters and maybe cut a wedge shaped piece for under the rafters to give them the bird mouth. I'm going to add cross ties to flatten the peak but only 1 1/2" down. The gable end header holding the bean is made of 3 2x6 with 2 1/2" plywood spacers. I may add jack studs along the window to shorten the span. That should all help. don't have the funds to completely rebuild the dormers.
Oh and add a few blades to that fan.

that is a good idea to use the spray foam as no rafter furring will be needed with the foam. if there is room(ceiling height) to use a 2x4 for the ties, they will be easier to work with than using 2x2's. adding full length jacks around the window is a good idea as it will strengthen the outer wall by adding the full studs to it too.