Wood Thermally-Broken Wall Studs

When it comes to building homes and other structures, there are many different materials and designs to choose from. One of the most important elements of any structure is its framing, which provides the framework that supports the weight of the building and provides the necessary stability. As we advance up the step code from Effective R22 to R40 , a thicker wall is needed. In recent years, there has been increasing interest in using thermally broken studs in place of traditional 2x10 lumber for framing. In this blog post, we'll take a closer look at why a thermally broken stud is needed and why it may be a better option than a 2x10.

First, let's define what a thermally broken stud is. A thermally broken stud is a framing member that has a reduced material section that allows additional  insulating material to be  placed between the two pieces of wood that make up the stud. This insulating layer helps to reduce the transfer of heat and cold through the wall, which can help to improve the energy efficiency of the building. Here’s an example below.

So, why is a thermally broken stud needed? The main reason is that traditional 2x10 lumber is not very energy efficient. Wood is a good conductor of heat, which means that it can allow heat to escape from a building in cold weather or allow heat to enter a building in warm weather. 

 It's worth noting that thermally broken studs are not necessarily more expensive than traditional 2x10 lumber. While the initial cost may be slightly higher, the long-term savings in energy costs and the increased durability of the framing can more than make up for the additional expense. The thermally broken stud there is an added price security that can help defeat the fluctuating cost of dimensional lumber.

There is a significant difference of quality between a 2x10 and thermally broken stud. These engineered studs won’t have the twist, bow, splitting, shrinkage, and wane that the traditional 2x10 will have. Traditional 2x10 lumber is vulnerable to rot, insect damage, and other types of deterioration. Over time, this can weaken the framing and compromise the structural integrity of the building. Thermally broken studs, on the other hand, are less susceptible to these types of damage. The insulating layer can help to protect the wood from moisture and insects, which can help to extend the lifespan of the framing.

BOSS Intentions with thermally broken studs:

• Keep structural load to the inside and follow advanced light wood framing elements

• Sheathing layer to the inside (for a number of benefits)

• Thermally break exterior connections

• Designed for lightweight cladding materials 

• BOSS is currently using a web truss but advancement in manufacturing and testing show the potential for an improved Wood Thermally-broken wall studs as shown in the examples below.

As of today there are multiple solutions available in the market available for use. Each one uses their own system or spin on how they thermally and/ or structurally modify their wall assembly.

T-stud is an example where they have a double stud assembly joined by a dowel connection through the length of the stud. The stud can come in differing dimensional sizes to help accommodate large structural requirements or thicker wall assemblies. T-studs offer a couple of different options such as the Bare Naked and Warm Stud.

Adaptive Homes recently launched their own wall assembly utilizing a Larsen Truss system. This system uses dimensional lumber joined by various OSB or Plywood gussets along the length of the studs. This provides a significant thermal separation and flexibility on the dimensional lumber used in the truss component.

Collective Carpentry released their C-stud component that provides a thermal separation from their structural dimensional lumber. In this wall, the inner C-joist chord typically lines up with the outside edge of the building’s footprint, while part of the C-joist cavity “hangs off” as an outrigger from the building, planing down to exterior insulation installed outside of foundation stem walls, slab on grade, etc

Although not an entire building assembly, the new PKI15 Vertical Flange joist from Pink Wood represents the latest innovation from their joist product line.  With its unique vertical flange orientation and 1-1/2” width, the PKI15 is easily installed as a whole house solution.

This solution was not designed specifically for vertical load, but has potential to be adapted in the future. 

Unity homes, a design-build company with an innovative, well-developed prefabrication process out of New Hampshire, use the Nordic I-Joist as their stud component. Shown in the photo below, a member of Unity is installing a component in their wall assembly line.

The B.PUBLIC Prefab component system is designed and assembled to create a building’s structure & thermal envelope. B.PUBLIC panels utilize code-compliant wood framing & sheathing.  The system is thermal-bridge-free, vapor-open, air-tight, and super-insulated with dense-packed cellulose (sound familiar). This system uses the Steico I-joists as their thermal bridge free component.

In conclusion, there are many reasons why a thermally broken stud may be a better option than traditional 2x10 lumber for framing. By reducing the transfer of heat and cold through the walls, resistant to damage, and price security. If you're planning a building project, it's worth considering the benefits of thermally broken studs and whether they may be a good choice for your project.