Should I Choose SIPs or Timber Frames?

3 August 2020 Kelly Newlands

Modern building has seen a move away from brick and blockwork as the market identifies building methods that are faster, warmer and greener. Both structural insulated panels and timber frames have these increasingly sought-after qualities, and can achieve fairly similar levels of construction speed and thermal performance. Though both options are timber-based, there are a lot of differences that separate them.

Structural insulated panels are ideal for self builders wanting to achieve high-performing, energy-efficient homes. As their name suggests, SIPs come pre-insulated to such high standards that, even without additional insulated liners, they can achieve U-values as low as 0.17 W/m²K. Adding suitable liners can get this number down to as low as 0.1 W/m²K.

SIPs support loads by their very nature as composite structural panels, and the boards are bonded to the insulation they sandwich to prevent buckling. This reduces the need for struts and supporting trusses, particularly where roofs are concerned, making them ideal for loft conversions.

SIPs are prefabricated in a controlled factory environment. The highly accurate cutting process allows for the fabrication of multiple identical panels, saving both time and money.

Where SIPs are slotted together, joining splines are used which virtually eliminate thermal bridging and provide a high level of airtightness. The erection of a SIPs house can take 60% less time than a conventional timber frame. For more information on Kingspan TEK™, our SIPs offering, click here.

In general, timber frames are more economical than SIPs, so are a good option for people wanting to achieve thermal efficiency on a budget, as SIPs can be around 15% more than timber frames.

Timber frames support loads by regularly spaced studs, with the panels then filled in with insulation. Since the timber frame is the load-bearing element, any brickwork that will act only decoratively rather than structurally must be tied back to the frame using special timber-frame wall ties to support the cladding. This timber superstructure makes timber frames an ideal choice for open-plan layouts, as internal walls are not load bearing.

Many of the build components are measured and fabricated in the factory, leaving only the final assembly to be completed onsite. This results in less inconsistencies and lower labour costs, since the bulk of the assembly is carried out offsite.

For more information on the two timber frame build systems we offer, click here.

The good news is that SIPs and timber frames can be hybridised. This can help bring costs down while still delivering on thermal efficiency. Timber-frame walls supporting SIP panels on the roof will retain heat efficiently while also giving you the option for loft conversions. The composite load-bearing nature of SIPs frees up a lot more space than another build system.

There’s no clear answer here. Both build systems perform exceptionally in terms of thermal efficiency and they are both faster and more efficient to erect than masonry systems. They also both have slim profiles that can release additional floor space into the property. SIPs outperform timber-frame systems in terms of airtightness, but they do so at a higher price. Their airtightness levels are so good that a mechanical ventilation and heat recovery (MVHR) system is often required to ensure air is kept fresh and circulated, the costs of which vary greatly.

So, if you want to build an exceptionally insulated Passivhaus, then SIPs are the method for you. If you want an energy-efficient house that still achieves levels of thermal performance superior to the national standard, then timber frames are the right fit.

Should I Choose SIPs or Timber Frames?

SIPs

Timber frame systems

Hybridisation

So which is best?

Kingspan Timber Solutions