System 01 · Signature
A drained, back-ventilated wall that carries heavy cladding, holds continuous insulation, and breaks the thermal bridge — so the assembly actually delivers the R-value on the drawings.
The principle
A thermally broken sub-girt system is a building-envelope detail for steel-framed and metal buildings in commercial and industrial applications. It improves energy efficiency by minimizing the heat transferred through the structure's metal components — while providing a strong, continuous fixing point for siding or cladding and a ventilated cavity that keeps the wall dry.
Starts with the air/vapour barrier →
The assembly
From the sheathing out — each layer detailed to hit thermal, moisture and fire performance.
A weather-resistant barrier (WRB) or air/vapour barrier over the sheathing that prevents moisture infiltration and delivers air-tightness. Self-adhered or liquid-applied membranes, per the wall assembly.
A connector that reduces heat flow between metal cladding and structure. The thermal break cuts energy loss and prevents the cold-spot condensation that plagues continuous-metal attachments.
Typically 18-gauge galvanized steel members, horizontal or vertical, that support the exterior cladding and create the gap for insulation between girt and finish.
Continuous insulation set between the sub-girts — e.g. Rockwool CavityRock semi-rigid, or IKO Enerfoil polyiso rigid board — for temperature, sound, moisture and fire resilience.
Cladding installs onto the outer flange, leaving a drained, back-ventilated air gap. Illustrative section — not to scale.
Z-bars · Z-girts · Z-channels
Z-bars are structural metal or fiberglass furring members that secure rigid insulation to exterior walls while providing a strong, continuous fixing point for your siding or cladding. They let you anchor heavy claddings — fiber cement, wood, adhered masonry — into the framing studs rather than through soft foam.
| Profiles & sizes | Web depth matched to insulation thickness. Webs typically 1″–6″; flanges commonly 1″–2″ wide. |
|---|---|
| Materials | Roll-formed galvanized steel, aluminum, or fiberglass. |
| Water evacuation | Exterior Z-bars are often perforated so trapped moisture or condensation can escape. |
| Load support | Anchor heavy claddings directly into wood or steel studs — not through the foam. |
| Thermal option | Fiberglass Z-girts or offset clip systems reduce metal-to-metal thermal bridging. |
Why the thermal break matters
Z-bars hold rigid foam panels in place — but continuous metal Z-girts transfer temperature through the fasteners, reducing the wall's effective insulation value. To maximize energy efficiency we specify fiberglass Z-girts or offset clip systems that interrupt the metal-to-metal path.
Get a spec review →Install a reliable weather-resistive barrier or house wrap over the sheathing.
Align girts over the studs and drive heavy-duty structural screws through the girt, the rigid insulation, and into the wood or steel studs.
Cut and fit rigid foam boards — EPS, XPS or polyiso — snugly into the channels between the Z-bars.
Use the outer flange as a sturdy nailing base to install the exterior siding or cladding.
The payoff
Performance benefits that compound over the life of the building.
A true break minimizes heat transfer between interior and exterior, keeping indoor temperatures consistent.
Less thermal bridging means lower heating and cooling costs — the HVAC system works less to hold setpoint.
Fewer cold spots on the interior reduces the risk of mould growth and insulation damage.
Reduced temperature fluctuation eliminates the hot and cold spots created by thermal bridges.
Less expansion and contraction with temperature swings extends the life of building materials.
Lower energy demand shrinks the carbon footprint and supports green certifications like LEED.
Higher up-front cost is repaid through energy savings and reduced wear on HVAC systems.
Thermal breaks help the wall meet energy codes and standards more easily.
Products & partners
We build assemblies around proven materials — barriers, clips, girts and insulation — selected for your performance targets and budget.
Common questions
Straight answers on thermal breaks, Z-girts and code.
It's a rainscreen wall assembly where the cladding fastens to sub-girts (Z-girts) that stand off the structure over continuous insulation, with a thermal clip that interrupts the metal-to-metal path. That thermal break stops heat from bypassing the insulation, so the wall reaches its intended effective R-value.
Z-girts give a strong, continuous fixing point that lets you anchor heavy cladding — fiber cement, metal panel, wood — directly into the studs rather than through soft foam, while holding the insulation in place. Perforated exterior Z-bars also let trapped moisture escape.
Yes. Adding continuous insulation and breaking the thermal bridge helps commercial and multi-family walls across the GTA meet current energy-code and effective-R-value targets. We detail each assembly to your specified performance.
We install ACM and metal panels, insulated metal panels, fiber cement and high-density panels, and architectural metal siding — all onto the same engineered, back-ventilated sub-girt assembly.
Start your project
Send your drawings or specs. We'll review the assembly and reply with a scope and timeline — usually within one business day.
Licensed & insured · WSIB · Serving Toronto & the GTA since 2012