Summary
The “Exterior Foam Net Zero” assembly provides a very well-insulated net-zero solution. Of all the assemblies in the ENBIX wall assembly library, SAIT GBTAC staff found this one to be the most difficult to construct. Framing of the structural wall was very straightforward, as it uses the same process as the “Business as Usual” tier 1 2×6 assembly, but the exterior insulation made it difficult to work with.
Videos showing key highlights of the wall from the interior and exterior.
Advantages:
- This assembly achieved the highest calculated effective thermal resistance of all selected and new-build assemblies, with or without the 2×6 cavity being insulated.
- Wrapping the exterior of the wall assembly with insulation reduces the amount of thermal bridging through the assembly.
- Utilizing the WRB as the air control layer allowed for less challenging detailing and a reduced chance of errors at junctions and penetrations compared to locating the air control layer in the interior of the assembly.
Disadvantages:
- It is the most expensive to construct – roughly 160% more to construct this assembly than the “Business as Usual Assembly”.
- Self-adhered membranes were difficult to work with.
- Some materials could not be found at a common hardware or building supply store and needed to be custom-ordered.
- It may be difficult to find tradespeople who can or are willing to install this type of assembly in a residential setting.
Image from: p.11, High Performance Wall Assembly Project Summary Report
Taking a deeper dive
Read the full report from SAIT to take a closer look at:
- Wall assembly drawings, sections and details
- Photos of construction
- Constructability and affordability analysis
- Effective thermal resistance calculations
- Comparison charts with other walls in the ENBIX library
Click here to see the energy modelling results for this assembly. Compared to a typical existing home in Alberta, this assembly’s energy consumption is reduced by 26.17% (the most!). Read our blog on the energy modelling of the ENBIX wall library here to understand a bit more of the story.
The assemblies are also modelled in 3D by Beyond Code and are best viewed from a computer. Click on the links for the 3D models below.
Exterior Foam Net Zero Assembly – with steel studs instead of wood framing members:
- Window Detail
- Exterior Wall – Electrical Penetration Detail
- Exterior Wall – Duct Penetration Detail
- Foundation Detail
- Roof Detail
The rest of the ENBIX wall library is also available as 3D models here.
