SOPREMA building with overlaid technical drawing, showcasing SOPREMA's architectural and construction expertise.

The construction industry is changing! Driven by the pressing need for more energy-efficient buildings, the National Energy Code for Buildings (NECB) has undergone significant revisions (in 2015, 2017 and 2020).

The enhanced effective use of insulation (including a more stringent accounting for thermal bridging), the introduction of innovative materials and construction methods, and improved guidelines for window and door installations are examples of market responses to these changes and requirements. Other energy codes and building standards, such as the BC Energy Step Code and the City of Toronto Green Standard, and the popularity of Passive House and Net Zero Energy Ready (NZER) construction are further examples of this trend towards the construction of thermally efficient buildings. Each of these developments reflects Canada’s commitment to environmental sustainability, reducing the energy consumption of buildings and achieving broader carbon reduction goals. Even though these changes are a step forward, they can be extremely challenging for the professional community responsible for designing and constructing new and retrofit buildings. And this is just the beginning!

SOPREMA wants to be part of the solution. We are proud to introduce the SOPREMA Protected Assembly as an extension to the BUILD BETTER wall assembly initiative; this assembly provides a strategy to meet more ambitious energy targets without necessarily requiring the normally expected increase in construction costs.

SOPREMA Protected Assembly

SOPREMA Protected Assembly is an exterior wall assembly that combines two types of exterior insulation: SOPRA-ISO V (polyiso) and mineral wool installed with the ACS THERMAL CLIP system. The combination of these materials allows for wall assemblies that are more thermally efficient and more resistant to fire exposure. In fact, the strengths of both insulation materials complement each other to provide a wall assembly with higher performance. 

SOPRA-ISO V is a foam plastic insulation that offers some of the best thermal performance available on the market. In addition, it is a thermoset foam plastic insulation that chars (does not melt) when exposed to fire, providing good fire resistance while still being a combustible insulation. Mineral wool is known for its non-combustible nature; however, its thermal efficiency is significantly lower than SOPRA-ISO V. Overlaying the SOPRA-ISO V with mineral wool provides a level of fire protection suitable for use in Non-Combustible Construction. 

Therefore, using a 2-inch layer of mineral wool to encapsulate SOPRA-ISO V and thus protecting it from fire is a combination that allows one to get the best of both insulation materials – the thermal efficiency of SOPRA-ISO V and the fire protection provided by mineral wool. 

The SOPREMA Protected Assembly provides the design community with another viable option for exterior insulation in Non-Combustible Construction (as opposed to mineral wool alone) – a high-performance and innovative insulation strategy that does not compromise fire and life safety. 

In addition to being thermally efficient and suitable for Non-Combustible Construction, the SOPREMA Protected Assembly is also cost effective, can be easily built and has a low carbon impact.  

Thermally Efficient

The thermal efficiency of the SOPREMA Protected Assembly is achieved by maximizing the R-value of the insulation strategy and reducing the thermal bridging created by the cladding attachment system. In other words, by changing the way the assembly is designed and optimizing the choice of components, the thermal performance can be significantly improved.

Maximizing R-Value

Each material in a wall assembly has an R-value or thermal resistance which represents a material’s ability to reduce heat flow. The higher the R or RSI value, the lower the heat transfer. Assuming everything else in the assembly is the same, a building can use less of an insulation material that provides a higher R-value per inch. Conversely, a lower R-value per inch insulation requires a greater thickness of material to reach the same thermal performance. 

For example, a nominal R-value of 30 would require 7 inches of mineral wool or 5 inches of SOPRA-ISO V. Consequently, it would take 2 inches less of SOPRA-ISO V compared to mineral wool to get the same nominal insulation value. That could result in major cost savings on a project! 

Thickness required to obtain a nominal R-30

Mineral wool = 7 in

Rock Wool PanelsRock Wool Panels

SOPRA-ISO V = 5 in


The SOPREMA Protected Assembly using the ACS THERMAL CLIP positively impacts the Clear Field Effective Thermal Performance. Efficient Interface Detailing is critical for achieving superior Overall Thermal Performance. See White Paper “BUILD BETTER – Optimizing Walls Today to Build a Better Tomorrow” for more information.

Clear Field, Interface Details and Overall Thermal Performance (BETBG V1.6)

“Clear field assemblies are wall, roof or floor assemblies that include all the components that make up a wall, including structural framing. These are typically found in the architectural drawings in the wall/roof/floor schedules. Clear field assemblies can contain thermal bridges from uniformly distributed secondary structural components which are needed for the wall to resist loads, but do not include thermal bridges related to intersections to the primary structure or between assemblies. Examples of components included in clear field assemblies are brick ties, girts that support cladding and/or studs.

Interface details are changes in construction or geometry that interrupt the uniformity of the clear field. These are typically found in the detail sections in architectural drawings. These include slab edges, opaque to glazing or wall transitions, parapets, corners and through wall penetrations.

Determining the impact of heat flows through the clear field and through interface details is necessary to accurately assess the thermal transmittance of building envelope assemblies. The overall U-value for a building section can be found as long as the thermal performance values for the clear field, linear and point transmittances are known along with the quantities determined by architectural drawings.”

Reducing Thermal Bridging

Some materials, like insulation, have a positive impact on thermal performance, while others, like structural studs or girts, have a negative impact. The amount of insulation required in a wall assembly is greater if significant thermal bridging exists. In fact, the thermal performance of a wall can be reduced by 50% or more based on the cladding attachment alone. Realistically, it is impossible to design and construct an exterior wall assembly and fully eliminate thermal bridging. For example, fasteners for insulation panels, exterior cladding and other structural components are essential. However, a wall assembly design should always consider limiting the thermal impact of these elements. 

As previously mentioned, cladding attachment systems have a significant impact on the overall thermal efficiency of a clear field wall assembly. While all cladding attachment systems must meet the primary purpose of structurally supporting the exterior cladding, the various types are neither thermally nor structurally equivalent and must be selected with care.

Wall assembly with galvanized Z-girtsWall assembly with galvanized Z-girts

Still very common in the industry, galvanized Z-girts are by far the least thermally efficient choice of cladding attachment and therefore require thicker insulation to make up for significant thermal bridging when compared to other walls. In many cases, NECB compliance may not even be achievable.

Wall assembly with ACS thermal clipsWall assembly with ACS thermal clips

A clip and rail system is a more thermally efficient solution than Z-girts. There are many clip and rail systems available on the market delivering varying levels of structural and thermal performance. The materials used to manufacture the various types of clips can in part account for differences in thermal conductivity and structural capacity. The stainless steel ACS THERMAL CLIP is one of the most thermally efficient cladding attachment solutions available.

To demonstrate the impact of various cladding attachment methods and insulation strategies, here is an example of an exterior insulated wall with steel studs (16 inches on centre) with either mineral wool or the SOPREMA Protected Assembly as exterior insulation. The comparison includes ACS THERMAL CLIP and two other clip systems (spaced 16 inches horizontally and 48 inches vertically), plus galvanized Z-girts (spaced 16 inches horizontally and 24 inches vertically).

According to the information above, clear field wall assemblies with the ACS THERMAL CLIP have a higher effective R-value at every thickness of exterior insulation as compared to wall assemblies using other clip or girt systems. Also noteworthy, the thermal performance is significantly higher when using the SOPREMA Protected Assembly. 

Without a doubt, Z-girts are the least efficient of the cladding attachment solutions shown. When using horizontal Z-girts for example, even with 6 inches of mineral wool insulation, the wall assembly effective R-value is only R-15.5. This is not sufficient to meet the NECB energy requirements for any climate zone. In fact, as a result of the high level of thermal bridging using a Z-girt cladding attachment, this assembly will need more than 6 inches of insulation to be code compliant, which can be expensive and a challenge to build. 

Thermally broken clips will perform better than traditional galvanized Z-girts, but the efficiency of the clips varies depending on their composition and design. The efficiency of a clip system is a very important attribute to consider to maximize the overall thermal performance of a wall assembly.

Among the options shown below, a designer could either choose to maximize the performance by using the SOPREMA Protected Assembly and benefit from a higher clear field effective R-value (e.g. No. 1) or optimize the thickness of insulation to meet a specific thermal performance target by using the SOPREMA Protected Assembly and benefit from major cost savings (e.g. No. 2).

Clear field wall assembly effective R-value using 6 inches of insulation (mineral wool or SOPREMA Protected Assembly), or the thickness of insulation needed to achieve R27 clear field wall assembly

SOPREMA Protected Wall AssemblySOPREMA Protected Wall Assembly


6-inch insulation:  
4-inch SOPRA-ISO V ALU + 2-inch Mineral wool

5 inches

Wall assembly with ACS thermal fastenersWall assembly with ACS thermal fasteners


6-inch mineral wool

6 inches

Wall assembly with the fiberglass clips systemWall assembly with the fiberglass clips system


6-inch mineral wool

6.5 inches

Wall assembly with galvanized clips systemWall assembly with galvanized clips system


6-inch mineral wool

7.5 inches

Wall assembly with horizontal Z-girts galvanizedWall assembly with horizontal Z-girts galvanized


6-inch mineral wool 

Not possible

Suitable for Non-Combustible Construction

Much attention has been directed to wall construction and fire prevention. In addition to active fire protection (sprinklers, fire suppression, smoke detection, etc.), the fire resistance of wall assemblies can be passively improved through good design principles and practices (compartmentalization, encapsulation, fire-rated assemblies, etc.). North American fire and life safety regulations are based on allowing occupant egress (time to leave the building) and property protection based on passive and active design to achieve this.  

Although there are fewer restrictions in the types of insulation materials that are used in Combustible Construction, market perception is that the only insulation option for Non-Combustible Construction is to use mineral wool (or another non-combustible insulation).

The SOPREMA Protected Assembly offers a pathway to include SOPRA-ISO V that reduces the risk associated with combustible materials in Non-Combustible Construction (confirmed by testing) and has the added benefit of enhancing the overall thermal performance of the exterior wall without necessarily requiring thicker insulation and increasing the expense of the wall assembly.

Wall assembly options are important moving forward as building developers, designers and contractors are being challenged to meet the increasingly stringent energy code requirements, while at the same time remaining code compliant from a fire safety perspective. A strict set of building codes and standards help to ensure compliance and provide a pathway to validate a wall assembly’s fire safety by way of small- and large-scale material and assembly testing.

Small- and large-scale testing referenced in the National Building Code of Canada (NBCC) can be used to provide information evaluating the use of combustible and non-combustible materials. The most critical large-scale test for wall assemblies is CAN/ULC-S134 Fire Test of Exterior Wall Assemblies.

CAN/ULC-S134 provides a test method to evaluate wall assemblies containing combustible components to validate their use in buildings required by the NBCC to be non-combustible. This test involves the exposure of a three-storey exterior wall to significant flaming from a window on the first storey and is intended to examine whether unacceptable flame spread will occur because of combustible components on or in the wall.

The NBCC, while complex, provides a logical pathway, including using the CAN/ULC-S134 wall assembly test, to demonstrate compliance.

NBCC pathway to demonstrate compliance with noncombustible construction and exterior claddingNBCC pathway to demonstrate compliance with noncombustible construction and exterior cladding

SOPREMA wants to ensure that buildings are constructed safely, offering peace of mind while not compromising performance. To provide a pathway forward to meeting increasingly stringent energy codes while ensuring full compliance with building codes like the NBCC, SOPREMA has undertaken a series of CAN/ULC-S134 fire tests to demonstrate wall-assembly building-code compliance using a combination of combustible and non-combustible insulating materials, air barriers, cladding attachment solutions and waterproofing accessories.  

The SOPREMA Protected Wall Assembly has successfully passed multiple CAN/ULC-S134 fire tests.  

Man pointing at a protected assembly wallMan pointing at a protected assembly wall
Mock-up wall with windowMock-up wall with window
Fire test on protected wall assembly Fire test on protected wall assembly

Cost Effective

In addition to being thermally efficient and suitable for Non-Combustible Construction, the SOPREMA Protected Assembly is also cost effective. The main contributor of these cost savings is the ability to use less insulation to achieve the same energy targets.

While we invite contractors and professionals to see the cost savings for themselves with their own cost of materials, we estimate that:

Using the SOPREMA Protected Assembly allows savings up to 40% on material (insulation and cladding attachment), compared to other assemblies that use only mineral wool as an exterior insulation and perhaps a less efficient cladding attachment solution.

Comparing wall assemblies that use mineral wool only as an exterior insulation, choosing ACS THERMAL CLIP may allow for savings up to 20% on material, compared to other thermally broken clip systems.

For example, an 8-inch exterior insulated wall assembly using the SOPREMA Protected Assembly will be 60% more thermally efficient (R-47.5) at no extra cost when compared to a wall assembly using mineral wool only with a thermally broken clip (R-30). Just by changing the insulation strategy, you can gain thermal performance without increasing cost. 

In addition, the savings increase when the thermal efficiency requirements increase.

Old Crew building under construction with SOPREMA productsOld Crew building under construction with SOPREMA products

Even if the main contributor to these cost savings is the reduction of the amount of insulation required, there are also other possible cost savings that are more challenging to demonstrate but still interesting to consider:

  • Changing the thickness of the wall by replacing mineral wool with SOPRA-ISO V may reduce transportation fees (less weight and material).

  • Reducing the wall thickness can also reduce the materials required for the window and door openings.

  • Having a thinner wall allows more available occupied space (can be valuable if the building is sold or rented by the sq²).

  • Reaching a more ambitious energy target with relatively minimal upfront construction costs can result in greater operational energy savings in the long term.

  • With the ACS THERMAL CLIP, there may not be a requirement for additional girts or rails, thanks to their ability to attach vertically or horizontally with no thermal penalty.

  • With the ACS THERMAL CLIP, the vertical spacing can be maximized as compared with other less structurally capable cladding attachment systems.

Can Be Easily Built

As with any evolution, changing the way you design and build can be challenging at first. That is why the SOPREMA Protected Assembly is as flexible as possible.

Installing the SOPREMA Protected Assembly with multiple layers of insulation would be comparable to other systems requiring the same number of layers. If the SOPREMA Protected Assembly (requiring a minimum of two layers of insulation) is compared to a system that can be installed in only one layer, installing the second layer will be more labour intensive.

In this case, the other performance benefits of the SOPREMA Protected Assembly are required to be sufficiently considered when choosing your wall assembly strategy. 

The SOPREMA Protected Assembly is an exterior insulation strategy that can be used with the most common back-up walls, including exterior insulation and split insulated wall assemblies.

There are also benefits in using ACS THERMAL CLIP as the cladding attachment system:  

The ACS THERMAL CLIP is straightforward to install with rigid insulation (this is not the case with all thermal clips), and often times, 48-inch vertical spacing is sufficient structurally to support the cladding load and optimize the installation of rigid insulation.

The ACS THERMAL CLIP often requires less sub-girt layers than typical clip and rail systems (which can save installation time and material cost).

Sub-girts and rails are not required to be proprietary. Contractors can fabricate what is necessary for a project, as long as they meet the minimum structural requirements.

The SOPREMA Protected Assembly proves that building more efficiently does not have to be more expensive or difficult.

Low Carbon Impact

More and more designers evaluate the environmental impact of the decisions they make throughout the design process. Whole building life-cycle assessment, the LEED v4 Building Life-Cycle Impact Reduction Credit, and requirements of a green procurement policy are only a few reasons why the design community chooses to evaluate the carbon footprint of buildings, including both embodied carbon and operational carbon.

Carbon Table Protected AssemblyCarbon Table Protected Assembly

The operational carbon footprint is directly linked to the energy required to condition the building (heating, air conditioning, and air circulation). 

Among the factors influencing operational carbon is the thermal efficiency of the building enclosure. Once an effective thermal performance target has been set (for the roof, walls, or foundations), operational carbon emissions become independent from the materials used, as long as the target is reached. Highly efficient exterior walls, such as those promoted as part of the SOPREMA BUILD BETTER Program, contribute to the reduction of operational carbon emissions. 

On the other hand, the embodied carbon footprint—which is attributable to carbon emissions from all materials installed on the building throughout their lifecycle—will be directly linked to the nature and quantity of materials used. Experts do not agree on the split between operational and embodied carbon for Canadian buildings (that is probably because it depends on a lot of variables), but it can be safely assumed that both are important.

Each insulation material used in exterior walls to reach the thermal performance target will be responsible for its share of embodied carbon emissions. As much as possible, data used to measure these emissions come from Environmental Product Declarations. EPDs disclose various environmental impacts, including the global warming potential, also known as embodied carbon.

The example above showed that for a thermal performance target of Reff 27, the SOPREMA Protected Assembly required a lower thickness of exterior insulation when compared to other solutions. The table below demonstrates the embodied carbon emissions attributable to the insulation of different wall assemblies providing Reff 27.

Assembly SOPREMA Protected Assembly ACS THERMAL CLIPS and Mineral Wool Fibreglass or Galvanized Steel Clips and Mineral Wool
Insulation SOPRA-ISO V ALU Mineral wool Mineral wool Mineral wool
Impact per inch of insulation [kg CO2 eq./m2] 4.9 6.65 6.65 6.65
Thickness 3 in 2 in 6 in 7 in
Impact [kg CO2 eq./m2] 28.0 39.9 46.6
Impact for Building [kg CO2 eq.] 28,048 39,944 46,601
Impact for Building [Mt CO2 eq.] 28.0 39.9 46.6

Embodied carbon emissions of an assembly using ACS THERMAL CLIPS with mineral wool are 14% lower than those of assemblies using mineral wool with fibreglass or galvanized steel clip systems. Using the SOPREMA Protected Assembly brings these emissions even lower, up to a 40% reduction (28 compared to 46.6). The overall reduction in insulation thickness through the use of ACS THERMAL CLIP and SOPRA-ISO V ALU, coupled with the selection of an insulation type producing less carbon emissions (SOPRA-ISO V ALU versus mineral wool), is responsible for this benefit.

For a building onto which 1,000 m2 of clear-field exterior walls are being installed, the carbon emissions avoided by choosing the SOPREMA Protected Assembly over other clip systems with mineral wool add up to 18.6 metric tons of CO2 eq. This is comparable to a commercial airplane making 186 round-trip flights between Montréal and Toronto.

Ambitious Energy Objectives, Exceptional Results at Old Crow

To conclude, the construction industry is undergoing a significant transformation in response to global environmental concerns, including rising energy prices and an increased awareness of sustainable practices. The SOPREMA Protected Assembly is a step forward to building better wall assemblies that are thermally efficient, suitable for Non-Combustible Construction, cost effective, can be easily built and have a low carbon impact.

Make your work easier by exploring our Build Better Guide, which includes all our tested and approved wall assemblies!