3 Common Ways to Build a Barndo
When designing a home using steel framing, there are a few things we need to control to reduce the likelihood of long-term damage, improve interior comfort, and reduce energy bills. In order of importance, the control layers are: water, air, vapor, and thermal (insulation). Controlling how water, air, and vapor enter/exit our home impacts the longevity and quality of a home. An analysis of the two most common methods for building a barndominium are provided below. Cost is also included in this analysis since very few people can build without worrying about budget.
Steel Exterior Walls with Wood-framed Interior Walls
In this construction method, a standard steel building is erected. A 2x4 wall is then typically framed inside the columns/girts. Insulation is typically a vinyl-backed fiberglass that is compressed between the girts and exterior panel or spray foam.
Pros
Most cost-effective option
Easy to acquire engineering approval for locations where engineering is required
Cons
No good way of preventing water, air, and vapor infiltration
Water/air sealing between the walls and foundation is typically poor
Spray foam can help to mask some of these issues
Water/air sealing around windows/doors is typically accomplished by liquid sealant
Metal on metal contact between exterior sheathing and framing reduces effectiveness of insulation
Steel Columns & Girts with Studs Between the Girts
Similar to the previous option, a standard metal building is constructed. In this case, studs (typically made from steel) are run vertically between the girts to allow for OSB or plywood along with an air/water/vapor barrier on the exterior of the building.
Pros
Exterior sheathing provides water, air and vapor barrier (like a traditional house)
Sheathing allows for easier and more effective sealing around windows/doors for improved water/air sealing
Easy to acquire engineering approval for locations where engineering is required
Cons
Direct contact between exterior sheathing and steel framing reduces effectiveness of insulation
Stud-Framed Walls Between Steel Columns and Rafters
Steel columns and rafters are erected similar to a standard metal building. The exterior walls are then framed with wood or steel studs (2x6, 2x8, or 2x10) between the columns. The studs allow for you to attach exterior and interior sheathing just like a traditional stick-built home. Options for windows and door sealing are also improved since all framed opening are made using studs. This reduces the likelihood of leakage in the future.
Pros
Exterior sheathing provides water, air and vapor barrier (like a traditional house)
Cons
More expensive (15%+) than other options
Can be more difficult to acquire engineering approval for locations where engineering is required
Overview
Although stud framing between steel columns is the most expensive method, it provides the best air/water/vapor sealing. For this reason, we recommend this option for those looking to build a barndo. For locations with strict engineering requirements, the option with studs between the girts can provide a more cost-effective yet effective alternative.
