Technical Topics

Design fundamentals for a Formance home

Design for less sun.

Formance homes will be highly insulated compared with a traditional framed home. Make sure you are not getting too much passive solar energy gain by including suitable shading.


Include mechanical ventilation in your spec.

The best form of mechanical ventilation is a heat recovery ventilation unit which ensures minimal loss of energy while also providing fresh air ventilation. Remember a house can't be too airtight, but it can be underventilated.


The Design Guide can be used without SED

The Formance Design Guide has been pre-engineered so SED is not required to sign off on the panel design except where your design is outside of the scope of the guide.


The surface of a Formance panel has a Group 3 rating, like plywood. An FRR of 60/60/60 can be achieved when the panel is covered with plasterboard. Ask us for this specific detail. Higher levels of firewalls can be achieved with specific engineering design. 


OSB is a timber product so it is subject to the effects of moisture ingress. It is also a very durable material, being the mainstream sheathing and flooring product used widely throughout the rest of the world. Formance SIPs are ok in the weather for up to 4 weeks typically before being wrapped. Of course, that depends on the weather, more wet days brings back the allowable time, more dry days increases it. 

Environmental Considerations

Choosing Formance SIPs is one of the most environmentally responsible choices you can make for your project. The OSB comes from SFI-managed forests and uses 85% of the usable timber on a tree, compared to 35% with framing. EPS is completely inert and harmless (we drink hot drinks from EPS cups, and store fruit and other foods in EPS containers), and it’s fully recyclable in New Zealand. Best of all studies have shown SIPs built with identical materials as Formance have a significantly lower CO2 footprint when compared to traditional timber-framed houses when considering whole-of-life impact. What about formaldehyde? All wood products have some formaldehyde in them, albeit at very low levels. OSB used in Formance SIPs has half the level typically found in plywood. 


Another advantage gained by choosing Formance is how well they withstand earthquakes. Our bracing tests proved they have more capacity than concrete hold-downs and we have had to down-grade the BU/m used in the Design Guide to reflect this. Formance SIPs are the safe choice when it comes to resisting damage from earthquakes. They are light, strong, and impact resistant. 


Formance SIPs can be used for inter-tenancy walls. Ask us for details used on projects to date.


By itself, a Formance SIP has STC ratings or around 22. This can be increased by the addition of other elements such as plasterboard or lightweight concrete.  Combinations of Formance panels and other items can be used to achieve STC values suitable for inter-tenancy situations. We have tested various combinations and can supply details for ratings up to STC 63. 


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