SmartWall and SIPs are not the same wall
People assume they are, and the assumption is understandable: both are prefabricated insulated panels made in a factory. The differences show up in wiring, in what you can change later, and in who has to engineer it.
What each one actually is
Structural insulated panels
A SIP is a core of rigid foam plastic insulation sandwiched between two structural facings, usually oriented strand board. They are used in floors, walls and roofs for residential and light commercial buildings.
SIPs are engineered by SIP panel specific engineers, manufactured under factory controlled conditions, and can be customized. The result is a system considerably more energy efficient than a conventionally framed wall.
The Pacific SmartWall
The SmartWall is built much like a conventional wall, with studs, but uses EPS insulation routered into the framing and leaves the inside face open. The exterior layer is fir plywood rather than OSB.
That construction gives superior thermal efficiency and airtightness, reduced sound transmission and shorter framing times, largely by minimising thermal bridging, the wood that carries heat between outside and inside.
Six differences that show up in practice
| SIPs | Pacific SmartWall | |
|---|---|---|
| Facing material | OSB glued to EPS insulation | Fir plywood, which is superior to OSB for structural integrity and seismic design |
| Running wiring | Holes must be cut into the OSB and the panel to chase wires through | The inside face is left open, creating a service cavity for wiring and plumbing |
| Studs | No traditional studs | Studs throughout, much like a conventional wall |
| Future changes | Moving a door or adding a window is limited by the lack of studs | Studs allow the wall to be modified later, and make fixing hardware straightforward |
| Engineering | A SIP panel specific engineer is required for seismic design | Any engineer can design the home; we ensure seismic and other requirements are met |
| Moisture | Managed by the assembly design | The dew point is eliminated, greatly reducing the possibility of moisture buildup in the cavity |
The hardware point sounds minor and is not. Towel bars, mirrors, exterior lights and hose bibs all need something solid to fix into, and a wall without studs makes each of those a small problem rather than a five minute job.
Where SIPs genuinely win
SIPs are a legitimate, well engineered system and a large improvement on conventional framing. They produce very high insulation continuity, they go up quickly, and for simple building forms with few penetrations they are efficient and effective. If future modification and service runs are not a concern for your project, they are a reasonable choice. The differences above are real, but they are differences rather than defects.
SmartWall and SIPs
A SIP is a structural insulated panel: a core of rigid foam plastic insulation sandwiched between two structural facings, usually oriented strand board. The Pacific SmartWall is built more like a conventional wall, with studs, EPS insulation and the inside face left open. The most significant differences are the facing material, the service cavity, the presence of studs and the engineering requirement.
The exterior layer of a Pacific SmartWall is fir plywood, where a SIP panel is OSB glued to EPS insulation. Fir plywood is superior to OSB for structural integrity and for seismic design, which matters anywhere with meaningful seismic requirements.
In a SIP wall, holes have to be cut into the OSB and the panel to chase wires through. A Pacific SmartWall uses EPS insulation with the inside face left open, which creates a service cavity on the interior of the wall. Wiring and plumbing run through that cavity, which makes both considerably simpler.
The Pacific SmartWall has studs in the wall, much like a traditional wall. Those studs let a homeowner make future modifications such as moving a door or adding a window, and they make it far easier to fix interior hardware like towel bars and mirrors, or exterior fixtures like lights and hose bibs. SIP walls lack traditional studs, which limits those options.
For SIP construction, a SIP panel specific engineer is required to design the home seismically. With the Pacific SmartWall, any engineer can design the home and we ensure the seismic and other requirements are met. That gives you a wider choice of engineer and more flexibility in the design.
In a Pacific SmartWall the dew point is eliminated, which greatly reduces the possibility of moisture building up within the wall cavity. A full year of testing at BCIT's Cold Weather Testing Facility showed reduced moisture buildup over time alongside the efficiency gains.
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