insulation frustration!

[PA-Buckeye]

Howdy fellas, long time no type!

I'm finally starting work on the interior of my garage/workshop. Despite my best efforts at researching what I need to do, I'm just getting more confused.

I've got Tyvek House Wrap (meets Type1 Air Barrier Req's.) on the exterior and I want to drywall the inside.

2x6 construction, Zone 5A central PA. The studs are full 8 footers with double top plates and double sill plates, so the full height is 8' 6". The guys stubbed in 6"-ish strips to fill the gap at the top of the wall. There are gaps in between the boards, covered by the Tyvek, but just by an inch or two above. Regular DL vinyl siding, ridge vent the full length of the roof.

One thing says "do this", another says to "do that" or "do this and that".

AAAAAaaaagggghhhhhhh!!!!!!!......eh...hmmm.....sorry.

My question:
Faced or unfaced? I really don't want moisture problems in my new space.

What do you all think?


Fancy picture attached below:




Dennis

 

[pattenp]

Use faced with the face to the heated side.

 

[bullnerd]

What he said.

Double top and double sill? Is that standard? I dont do that when I build stuff.

 

[PT Doc]

That would be a great placating for spray foam that batting or blown in.

 

[Steve in Mi]

My question:
Faced or unfaced? I really don't want moisture problems in my new space.

What do you all think?

Dennis

Either way, faced or unfaced, I would use poly over it anyway. The wider the poly the less seams/overlaps. 12' poly will give good overlap up on the ceiling and let it hang below the bottom plate (bridge the gap between wall and drop cloth for painting) - you can trim it after you put the wallboard up and paint. That is how I did mine.

 

[PA-Buckeye]

Thanks guys, I just wasn't sure if that was creating a double barrier or not.


bullnerd wrote:

Double top and double sill? Is that standard?

It's definitely beefy, that's for sure!

 

[bullnerd]

Pretty sure the housewrap will breathe enough to not cause a double barrier.

 

[rsa]

Unfaced with a latex painted drywall is what building scientists recommend for your climate zone 5.

The reason for unfaced is that it allows increased drying of the wall to the inside. The latex paint provides code required vapor control.

You don't have insulating sheathing, but Building Science Corporation's Insulating Sheathing Vapor Retarder Requirements is an easy read and applies directly to your walls. Uninsulated vinyl siding is considered a vented cladding.

The 2007 Supplement to the IRC currently defines vapor retarders under three classes:

Class I: 0.1 perm or less (Sheet polyethylene, non-perforated aluminium foil)
Class II: 0.1 perm <= 1.0 perm (Kraft faced fiberglass batts)
Class III: 1.0 perm <= 10 perm (Latex or enamel paint)

A more detailed reference is BSC's Research Report 0410, Vapor Barriers and Wall Design.

 

[rburke65]

I can understand your confusion.......so many expertsnon here, it's hard to know which one(s) to believe. All I can tell younis I did Tyvek, faced, the paneling. Don't know if it's right or....left! Im in Ohio, near the Pa. line.

 

[Rookie2]

make sure the tyvek is sealed with tape or air tight and that there is no gaps in your insulation. I used it on my metal morton bldg. No one believes me that air blowing in at the metal seams will kill your 'R' value.

 

[Kevin C]

From a structural standpoint not having the edge of the plywood on framing concerns me.

Assuming that wall has to be able to hold forces in sheer, I would add blocking between the sheets of plywood. That and the plywood sheathing helps to hold the top plate in place if you ever have up-lift forces on your roof.

This is assuming you put hurricane ties to hold your rafters down to your top plate, then you need the top plate held in place by the plywood.

Straps or sheathing on the inside would to the same thing.

As far as a barrier goes... A retarder is better. As RSA pointed out, the best case is if your walls can dry from both sides. A plastic barrier in the inside prevents drying to the inside and is usually reserved for extreme climates.

 

[Rob_b]

Seal your air gaps with insulation in a can. Use a vapor barrier either paper backed or preferred 6mil plastic with a sealant to the floor and tuck tape your joints. R20 insulation in the walls and ceiling. Drywall and taped joints(2 coats) then paint as needed. Heat with candle...good luck

PS...agree with Kevin...block those areas

 

[Bib Overalls]

I'm a big fan of closed cell foam. More expensive. Supper performance.

 

[Fun pain]

How do you plan to heat the garage? Makes a big difference on how to Vapor barrier a "Garage"... with cars going in and out and such?



Radiant heat
for example:

http://garagejournal.com/forum/showthread.php?t=185945&showall=1

Humidity becomes a problem.

if wood burner or any other type of heat source that burns/heats the air, moisture will be burnt out of the air, and humidity will be controled by flames from the heat source.


and is the concrete vapor barriered? Important too

 

[OccupantRJ]

From a structural standpoint not having the edge of the plywood on framing concerns me.

Assuming that wall has to be able to hold forces in sheer, I would add blocking between the sheets of plywood. That and the plywood sheathing helps to hold the top plate in place if you ever have up-lift forces on your roof.

This is assuming you put hurricane ties to hold your rafters down to your top plate, then you need the top plate held in place by the plywood.

Straps or sheathing on the inside would to the same thing.

As far as a barrier goes... A retarder is better. As RSA pointed out, the best case is if your walls can dry from both sides. A plastic barrier in the inside prevents drying to the inside and is usually reserved for extreme climates.

I am with Kevin on this one. My first concern would be support on those seams. They are going to turn into a ripple later on, and make the vinyl siding look buckled. Plywood warps easily in the cross direction. Even some 1x laid flat and the plywood screwed or nailed to them would help things.

 

[PA-Buckeye]

Concrete has vapor barrier. I'm leaning towards a direct vent gas heater or a minisplit heat pump. It's a small shop by GJ standards (16x32), but it's way bigger than the shop I don't have right now, lol.

IIRC, the ply sits on a 2x8 bottom plate with a 2x6 plate on top of that. The plywood strips up top are tied into the studs and top plates, there's just some of those gaps between pieces.

I really appreciate all the advice!

 

[6768rogues]

What he said.

Double top and double sill? Is that standard? I dont do that when I build stuff.

If the trusses or rafters sit directly above the studs, a single top plate is sufficient. If not, it needs a double. Frequently walls are studded on 16 inch centers and trusses are on 24 inch centers, so doubling the top plate is needed.