Structural insulated panels or SIPs are considered an advanced method of building because it replaces conventional timber frames with pre-fabricated insulated boards. Each panel is made using pressure treated sheathing and foam insulation core. In selecting a suitable SIP system for your project, it all boils down to deciding the type of insulation and jointing method. These two features are essentially what differentiates the options made by SIP UK panels manufacturers.
Cost of SIPs
Suppliers cannot provide a fixed amount on the cost of SIPs because it will depend on how complex the project is. The panels only account for a part of the cost of an entire build, and at the same time, other factors contribute to the totality of the cost of the building system. Other contributors include design, fabrication, delivery, and installation costs. On top of this, the supplier will add a mark-up for profit.
Lifespan of SIPs
Manufacturers claim that SIPs last approximately 60 years as the minimum lifespan. Historically, the earliest known SIP buildings in the US were constructed in the 1930s and the technology did not take off until the 1970s; hence, the performance of SIPs is only based on around 40 years of data. Nonetheless, during this time, it was proven that SIPs perform well and regardless of other building systems or type of insulation used together with the boards, the results appear to be consistent.
It is, however, essential to take into consideration that SIPs are not inherently moisture resistant. In case of a flood caused indoors or from the exterior of the building, SIPs will degrade due to their inability to dry out quickly.
Type and quality of insulation core
The two popular choices are EPS or expanded polystyrene foam and PUR or polyurethane foam core. An EPS foam core is generally less expensive and readily available. It is also possible to customise the thickness of the EPS foam core. In contrast, a polyurethane foam core injected into the boards has better insulation properties than EPS foam. However, polyurethane foam is more expensive than EPS foam.
Apart from the thermal performance of the foam core, another essential factor to take into account is minimising thermal bridging. The jointing method used in installing SIPs is generally responsible for creating thermal bridges in construction using SIPs. If structural stability is a priority, the best jointing method to use is timber spline, but this method results in thermal bridging. For long-term performance, dimensional timber spline joints are the best choice.
Structural stability of SIPs
The airtightness of a building using SIPs contributes to its structural stability. In general, SIPs are more structurally stable than conventional timber frame buildings. To prevent the boards from moving or creeping, dimensional timber spline joints minimise the overall impact of this phenomenon.
With all these factors considered, along with extensive research, you can make a final decision on selecting the right SIP system to use in your project.