Insulating a metal building | Ask Mason Knowles - SPF Consultant | Spray Foam Technical Questions and Answers | SprayFoam Magazine Q&A Forums

Q&A Forums

Author	Comments
bob brown Posted: Aug 13, 2009 03:27 PM	Insulating a metal building Is there any reason you couldn't use .5lb open-cell on a metal building? It's and old airplane hanger 40x40 with 2x4 frame walls. Thinking 3-5 inches. on walls and 8" in the 2x12 roof.
mason Posted: Aug 15, 2009 09:36 AM	Yes, open cell foam can be easily installed in a metal building. However, in cold climates don't forget to put a vapor retarder element on the warm side of the foam to reduce the amount of moisture vapor transmitted through the foam. Metal is a very good conductor and is a likely place for condensation if the moisture vapor is not controlled.
Corey Degetaire Posted: Aug 24, 2009 09:13 PM	What would be considered a vapor retarder element, and how is it applied? I am going to bid a metal building at the end of this week and this info would be very helpful when i talk to the owner. I was going to suggest 4" of OC foam or 1 1/2" of CC foam.
mason Posted: Aug 25, 2009 07:31 AM	A vapor retarder element can be quite a few things. For example, an intumescent coating may provide the required permeance (depending on the type and thickness). The building code requires a class 1 or II vapor retarder in climate zones marine 4 to 8. It identifies the following items as class II vapor retarders that would be required in cold climates; Kraft faced fiberglass batts or paint with a perm rating greater than 0.1 but less than 1.0, or sprayfoam with nominal density of 2 lbs per cubic foot applied to the interior cavity side of the sheathing where the sprayfoam meets or exceeds the specified insulating sheathing R-value (example: in zones 7 & 8 you would need R-10 of ccSPF in 2x4 studs and R-15 in 2x6 studs).
Gerry Wagoner Posted: Aug 25, 2009 08:55 PM	Try Davlin 900, or Vimasco 749. regards, oG

Author

Comments

bob brown

Posted: Aug 13, 2009 03:27 PM

Insulating a metal building

Is there any reason you couldn't use .5lb open-cell on a metal building? It's and old airplane hanger 40x40 with 2x4 frame walls. Thinking 3-5 inches. on walls and 8" in the 2x12 roof.

mason

Posted: Aug 15, 2009 09:36 AM

Yes, open cell foam can be easily installed in a metal building. However, in cold climates don't forget to put a vapor retarder element on the warm side of the foam to reduce the amount of moisture vapor transmitted through the foam. Metal is a very good conductor and is a likely place for condensation if the moisture vapor is not controlled.

Corey Degetaire

Posted: Aug 24, 2009 09:13 PM

What would be considered a vapor retarder element, and how is it applied? I am going to bid a metal building at the end of this week and this info would be very helpful when i talk to the owner. I was going to suggest 4" of OC foam or 1 1/2" of CC foam.

mason

Posted: Aug 25, 2009 07:31 AM

A vapor retarder element can be quite a few things. For example, an intumescent coating may provide the required permeance (depending on the type and thickness).

The building code requires a class 1 or II vapor retarder in climate zones marine 4 to 8.

It identifies the following items as class II vapor retarders that would be required in cold climates;
Kraft faced fiberglass batts or
paint with a perm rating greater than 0.1 but less than 1.0,
or sprayfoam with nominal density of 2 lbs per cubic foot applied to the interior cavity side of the sheathing where the sprayfoam meets or exceeds the specified insulating sheathing R-value (example: in zones 7 & 8 you would need R-10 of ccSPF in 2x4 studs and R-15 in 2x6 studs).

Gerry Wagoner

Posted: Aug 25, 2009 08:55 PM

Try Davlin 900, or

Vimasco 749.

regards,

oG

You need to login to reply to this topic. Please click here to login.