Can I Build a Two-Storey House with SIPs?

Here at Formance, we often get asked if you can build a two storey house with SIPs. The answer? Absolutely. SIPs (Structural Insulated Panels) are more than capable of handling two-storey builds — and are actually a far superior option compared to traditional methods.

Despite what some people think, SIPs aren’t just for tiny homes or cabins. With engineered design and correct detailing, two-storey homes (and even three-storey builds) are entirely achievable. SIPs are structurally strong, thanks to the continuous bonded skin-and-core system, which acts like an I-beam across the entire panel. When installed properly, SIPs can easily handle the vertical and lateral loads required for multi-level homes.

Key Benefits for Two-Storey Builds:

• Speed: SIPs go up fast. That’s a major benefit for complex two-storey sites where time and labour are often at a premium.

• Strength: Engineered spans and load calculations allow large open spaces without excessive internal framing. This makes it easier to create open-plan living areas both upstairs and down.

• Thermal performance: Energy efficiency is a given — your upstairs stays warm in winter and cool in summer, with fewer heating or cooling requirements.

• Design flexibility: You’re not locked into boxy designs. Architects can get creative and still use SIPs, including vaulted ceilings, large window openings, and cantilevered features.

What to Consider

Just like any building system, SIPs need to be designed properly. Roof truss loads, point loads from upper floors, and wall bracing are all part of the equation. SIPs don’t remove the need for good engineering — they simply make the execution faster and more predictable.

While working with a SIP-savvy designer can be beneficial, it’s not essential. Our system is so straightforward that almost any competent designer or builder can work with it confidently, without needing specialist knowledge. With the right input, your home will meet building code requirements, deliver excellent thermal performance, and stand the test of time.

The good news? The Formance Design Guide is already pre-engineered for two-storey construction. That means much of the work is already done before you even begin. And if you’re going for three storeys — we’ve done that too. It just requires Specific Engineering Design (SED), and we can assist you through that process to make it seamless.

Real-World Proof

Across New Zealand, Formance SIPs have been used on hundreds of two-storey homes — from lifestyle blocks to high-end architectural builds. In fact, many of our clients choose SIPs specifically because they’re building two levels and want the structural and thermal benefits to carry right through the design.

If you’re considering a two-storey home and care about strength, speed, and long-term energy performance, then SIPs should be at the top of your list.