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top of wall opening

gogolf0401

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Mar 25, 2015
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154
Location
West central MN
What do you guys typically do in regards to the wall opening at the junction of the wall/ceiling? I was thinking of foaming it shut since I will be foaming the walls.
 

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sands35

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May 29, 2012
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936
Location
St. Joseph, MI
Where are you going to put in ceiling insulation? Are you going to have a fully vented attic? or will that be conditioned space?

Pole construction? Did the joists get specced to hold the weight of a false ceiling?

If fully vented (with attic insulation on the top side of a ceiling and air gap between the insulation and the roof deck), then you need soffit vent baffle.

(these things):
http://www.homedepot.com/p/Amerimax...y-and-Soffit-Vent-in-Black-ACCUVENT/202962730

If you are foaming the walls, then install those prior to foam. The foamers should then seal the baffle up so you can do what you want with the ceiling insulation.

If you are going to foam on the bottom side of the roof deck, then just put in some cheep luan or something so you don't waste foam into the soffit space.

(IMHO - think hard about foaming up against the roof deck. In 20-30 years when the roof needs to be replaced, how hard will it be to get the roof off?)
 
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Highbeam

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Feb 15, 2011
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2,292
Location
Mt Rainier foothills, WA
I added another girt out of 2x lumber there between the roof and the topmost girt. It was tricky to block it in but it worked. Every foot or so I drilled a big 2" hole like bird blocking to allow air in. Then when I insulated the ceiling I had to lay out the first 4 feet of the attic with batt insulation that was low enough to allow ventilation clearance between the top of batt and the roof. That was easier than baffles. Then I blew in 15" of cellulose across the rest of the ceiling.

My trusses are 12' apart.
 
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gogolf0401

Well-known member
Joined
Mar 25, 2015
Messages
154
Location
West central MN
Where are you going to put in ceiling insulation? Are you going to have a fully vented attic? or will that be conditioned space?

Pole construction? Did the joists get specced to hold the weight of a false ceiling?

If fully vented (with attic insulation on the top side of a ceiling), then you need soffit vent baffle.

(these things):
http://www.homedepot.com/p/Amerimax...y-and-Soffit-Vent-in-Black-ACCUVENT/202962730

If you are foaming the walls, then install those prior to foam. The foamers should then seal the baffle up so you can do what you want with the ceiling insulation.

If you are going to foam on the bottom side of the roof deck, then just put in some cheep luan or something so you don't waste foam into the soffit space.

(IMHO - think hard about foaming up against the roof deck. In 20-30 years when the roof needs to be replaced, how hard will it be to get the roof off?)

Pole construction, 8' oc with trusses every 4'. Specced to hold steel ceiling and blown insulation along with 50# snow load. I bought the soffit vent baffles already, although when bending at the defined crease they are about an inch or so short. Will have blown insulation in the ceiling with duraliner steel ceiling.
 
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sands35

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Joined
May 29, 2012
Messages
936
Location
St. Joseph, MI
More gap to the roof is OK. You just want the side sealed up so wind can't blow down the edge of the ceiling insulation. Condensation can form if the air is really cold and it takes the corner of the ceiling/wall joint below dew point in the winter.
 
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gogolf0401

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Joined
Mar 25, 2015
Messages
154
Location
West central MN
I ended up just stapling 1/8" hardboard to the top of the wall opening. That way no critters will be able to chew through and get into the wall.

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sands35

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Joined
May 29, 2012
Messages
936
Location
St. Joseph, MI
Whatever works!

Where you going to spray foam or tape the little gaps? At least on the windy side of the garage?
 
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