Metal Building Insulation

We received an email from Tim in Southwest Oklahoma. He had seen the video we made of our adventures while constructing our metal building shop/house. His main questions centered around our experience with insulation. He wanted to know what type of insulation we used for the home and if we had experienced any problems with home sweating during the winter months. He also asked if Tom had any advice on how to prevent sweating. Thanks for the questions Tim and we will do our best to try and answer them. By the way, best of luck with your building project, Tim, and send us some updates and pictures for our website!

Tim is looking at building an all metal red I-Beam truss system with sheet metal exterior walls. The metal shop/house that Tom built is along those same lines as well. Tom used a basic rip stop vinyl faced fiberglass insulation. Insulation can be purchased without the rip stop feature, but if the temperature gets extremely cold and the insulation gets bumped the insulation could crack. Rip stop insulation is more durable. Tom’s entire building is outfitted with 3 1/4″ bat, R11 insulation and was purchased along with the entire building kit. The bats were 5 foot wide. The inside of the home was framed in the existing building once the building was erected and dried in. The wood stud walls of the house were insulated as well with R13 fiberglass bats, giving the home portion of the building an extra layer of insulation. This created dead air space between the bat insulation that was used to insulate the entire building and the insulation that was packed into the stud walls of the house. This helps elevate any type of large temperature variation between the outside and inside of the house. The air temperature in the dead air space tends to equalize in that zone.
To help answer Tim’s question as to how to prevent sweating in the walls, the shop/house is a great case study.
Tom notices that in the shop, where there isn’t a secondary wall system and the wall and roof structure consists of the tin, bat insulation, purlins and gurts, moisture can form on the building frame when the outside and inside temperatures vary greatly. The cold temperature from outside will interact with the point on the building where the insulation is compressed at the purlins because the tin is screwed in there. The insulation quality is low and the cold air transfers from the tin through the thin area of insulation onto the purlins. If there is any moisture in the shop, say from shop equipment or vehicles that have been pulled in to work on, the purlin temperature interacts with the moisture in the air and does cause a little sweating.
There isn’t much problem with the house part of the building sweating. Really only in typical areas like bathrooms and the kitchen while showering or boiling spaghetti noodles. This may be due to the double insulation factor.
The other thing to note is that Tom’s house/shop is located in an very dry location. Wyoming experiences low humidity year round. The important factor for any building project with regards to preventing sweating is still going to be a well ventilated building.