Insulation Question House Wrap

[gguertin]

I have a Metal building and some plans had changed. I had always intended on using a spray foam insulation but due to an electrical change I have enough room for fiberglass insulation now. The problem I see is I did not wrap the shed in Tyvek because I had intended to just spray directly to the metal.

Thoughts?
Could I put tyvak between the studs from the inside still?
Is spray foam really still the better option?

I live in MN and currently my plan is just to heat it although I could see putting a window air conditioner in to occasionally lower the temp in the middle of summer while out there working.

Thanks!

 

[jack stand]

"Metal building" as in the square tube carport type?
Your last question about tyvek, are you framing a separate wall just inside the exterior wall?

 

[gguertin]

I think its considered a carport type. The framing was added to the steel studs like this picture although its not complete yet.

 

[jack stand]

I didn't mean that in a derogatory sense (Carport type) and people's terms vary. Honestly I'm not sure of the correct term myself.
A couple of inches of closed cell blows away 31/2'' of fg.
Imho tyvek is not going to gain you much as you describe. It's an air infiltration product only and relies on a continuous "wrap" by means of long seamless application and tape where necessary. All on the outside of the framing.
Closed cell will accomplish this as well, but at a price. In MN I'd say buy once - cry once. It's an expense that gives back forever.

 

[gguertin]

Thanks!

 

[dfiler2]

I am in the far NW corner of MN, I had my shop spray foamed and am very glad I did. it's 28x38 and very easy to heat and cool, another advantage is that it heats up or cools down very quickly. Even when it's -30 the shop goes from 50 to 70 in just a few minutes.

 

[Damon L.]

A lot of builders were doing 2" of foam on the outside then filling with fiberglass a decade or so ago.

I am in MN, and insulated mine with R19 in the walls with no tyvek as it was a preexisting building.

 

[duneslider]

The problem you have is you need to try and air seal it. The spray foam will do a pretty good job of air sealing it all. You could use a tape meant for this and seal all the joints in the metal and then use the fiberglass insulation. If you don't do something to air seal the insulation won't do much good.

 

[Damon L.]

Housewrap isn't an air seal.

The insulation does plenty without a seal on the exterior.

I blew R50 fiberglass in my ceiling, which is very much not sealed on the outside of the insulation, and that does fine as well.

 

[Walkers]

Foam it!

 

[dcg9381]

Spray foam is always the better option compared to bat as it expands and seals. In my state, we spray straight on the metal sheeting and I've seen TONS of buildings done that way here. Factor in the cost of having to frame that shop in if you're going to do fiberglass.

The only issue I'd see with fiberglass is if you're in an area that the inside of that metal might "sweat" - IE, high humidity and you cool the building.