Steel garage insulation

[kaje36]

So, i got a deal on 75 sheets of PolyISO, and i am looking for install recomendations.

I could do full sheets ontop of the studs and tyvek tape the seams.
Or i could cut it into 2 foot strips, and either tyvek or greatstuff edges.

What do you all think?

 

[lakeroadster]

How thick are the sheets?

 

[kaje36]

They are 1.5 inch 4x8 sheets.

Thanks!

 

[kaje36]

The PolyISO is here! 75 sheets of 1.5 inch! Was only $15 each with free delivery!

 

[kaje36]

So, anyone got any install ideas? onto of the studs? or in the studs? or other ideas?

 

[CNGsaves]

^ ^ You're not going to like my answer . . . .

Take off outer steel skin and install your 1.5" insulation as "sheeting" and tape the seams. THEN put on Tyvek wrap and re-install the steel skin.

Once outside is done, then plan on MORE INSULATION between the studs inside as that little bit of outer insulation is not enough.

UPDATE GJ Profile with a Location. What levels of insulation really depend on your CLIMATE and your heating/cooling goals.

 

[readhead]

I don't know where the building is located, which could change my answer. The easy answer would be to rip the sheets to the proper width and attach them in place with glue made for foam.

 

[8mpg]

^ ^ You're not going to like my answer . . . .

Take off outer steel skin and install your 1.5" insulation as "sheeting" and tape the seams. THEN put on Tyvek wrap and re-install the steel skin.

Once outside is done, then plan on MORE INSULATION between the studs inside as that little bit of outer insulation is not enough.

UPDATE GJ Profile with a Location. What levels of insulation really depend on your CLIMATE and your heating/cooling goals.

I agree. Exterior rigid foam with taped seams is one of the best insulation methods.

 

[kaje36]

I did think about removing the exterior, but then I would have giant gaps in the corners since it would be 3 inches wider, and 3 inches longer then it was before I started with no ready source to match the existing skin!

Readhead: I was thinking of doing that for all the walls, then just mount to the studs for the roof, kinda a hybrid solution.... This garage is in New Hampshire, I mostly just want to keep the steel from sweating.

 

[My Old Tools]

Depends on your climate. If you have any extremes, I would foam the existing walls and "glue" the panels to it with the foam, making a 3" thick insulated wall with no gaps to tape.

 

[kaje36]

My Old Tools: I got a few quotes to sprayfoam the garage, and it was around $4500, even checked for DYI kits, and it was even more (4100 board feet.) I assume that's what you mean by "foam the existing walls"

 

[MagKarl]

I would probably cut the foam to fit between the girts and purlins. I would not remove the tin.

You got a great deal on the insulation, I'll bet you'll notice a great benefit despite concerns by some that it's not as air and vapor tight as spray foam.

 

[Al Bundy]

So, i got a deal on 75 sheets of PolyISO, and i am looking for install recomendations.

I could do full sheets ontop of the studs and tyvek tape the seams.

What do you all think?

You don't want to do that. In the winter you'll get moisture freezing on the underside of the metal and when it warms up it makes a heluva mess. Ask me how I know.

You would be way better off with a ceiling that's buttoned up tight and adequate venting in your roof to keep the air moving.

 

[kaje36]

You don't want to do that. In the winter you'll get moisture freezing on the underside of the metal and when it warms up it makes a heluva mess. Ask me how I know.

You would be way better off with a ceiling that's buttoned up tight and adequate venting in your roof to keep the air moving.

AL, You have me a bit confused, Do you are saying to not have a airgap between the steel and the foam? put it between the studs?, and just have a vent into the inside of the garage?

Or and air gap next to the steel with a vent into that airgap?

I would love to hear what happened to you! or if you have a link to the post?

 

[Al Bundy]

It's an ongoing issue that I haven't figured out how to solve yet. I bought a commercial building that has inadequate air flow in the attic spaces. During the cold months I get condensation freezing to the underside of the metal roof. Then when it warms up it melts off on finds it way onto the ceilings and in the walls of the building. In my garage I have plenty of ventilation to keep the air moving and I don't have that problem. I also installed a fan in the gable to pull the air out in the summer. It's hooked to a thermostat and starts when the attic temp hits 100. Needless to say, the space above that ceiling stays bone dry.