SIPS, or structural insulated panels are a fast and efficient way to achieve very high thermal performance.

In today's episode, we continue exploring prefabricated panel solutions. We investigate the design of a passive house built from SIPS on a very challenging site in the oceanic temperate climate of Wellington, in New Zealand. Architect Murray Robertson, the director of Robertson Architects, shares the inside story of his Bell House project.

Today we'll explore the process, benefits and costs of SIPs and when they're an ideal solution.

Australian Architects can claim formal CPD hours for these podcasts.

MORE INFORMATION

Find everything you need on the Renovation Collaborative website.

www.renovationcollaborative.com.au

• PODCASTKey points summary, timestamps and resource links
• FREE RESOURCESTranscript edited into clear Q&A.
• CPDAustralian architects can find more information on CPD, and
• COURSESEleven easy to read courses demystifying the entire home design and construction process.

KEY POINTS SUMMARY

1. Structural insulated panels or SIPs are used in floors, walls and roofs for residential and light commercial buildings. The panels are made by sandwiching a core of rigid foam plastic insulation between two structural facings and in this case Murray used oriented strandboard (OSB). SIPS are manufactured off site and are custom designed for each project.

2. SIPs panels do have some timber framing in them, but much less than a standard timber stud wall. The reduced timber content plus the polyurethane insulation deliver better thermal performance than standard insulated timber frame construction.

3. The external wall composition of this project was as follows:

• The basic external shell was a 165 mm thick SIPS panel.
• Externally, the ProClima weathertight membrane was fixed directly to the SIPS board and a 45x45 timber structural cavity batten attached to the outside of the membrane for the external cladding, and
• Internally, 45 x 45 timber battens were fixed to the SIPs, creating space for services, additional insulation and attachment for internal plasterboard lining.

4. Internally, the oriented strandboard lining can be exposed rather than covered with plasterboard to save costs, but this approach makes access to services much more challenging. Additionally, since the strandboard wall serves as the finished surface, it requires protection during construction.

5. SIPS are very airtight, making them very appealing for use in Passive House projects. Only the joints in the very large SIPS panels require taping.

And finally,

6. Important design considerations when using SIPs include:

• Lintels above doors and windows cannot be concealed within the ceiling, meaning that floor to ceiling glazing is not possible, and
• SIPS roof panels stop at the wall line resulting in no eaves overhang. Therefore, a custom solution to attach eaves is required.

INTERVIEW QUESTIONS

[00:00] Introduction

[00:55] How did you get started in sustainable design?

[03:19] What was the project brief?

[04:42] What is the Climate of Wellington in NZ

[05:27] What were the site issues?

[08:09] Why did your clients pursue Passive House?

[08:57] Tell us about the design of the structure?

[11:13] What are SIPS?

[12:51] What is the total wall composition?

[16:12] How are SIPS installed on site?

[18:42] Is any structure required or are SIPS load bearing?

[19:47] Can you expose the SIPS strandboard lining internally?

[21:23] Were SIPS cost saving?

[23:42] What materials were used on the building exterior?

[24:48] What is thermally modified timber?

[26:19] What doors and windows were used?

[27:18] What environmental materials did you choose for the interior?

[28:21] What is your opinion of Hardwax oils for interior timber floors?

[29:50] What advice would you give anyone considering using SIPS?

[31:05] Would you use SIPS again?

[31:55] Key points summary

IN THE NEXT EPISODE 

Next week we move on to our next sustainable design theme, Healthy Buildings.

We'll investigate the design of a house on an off-grid site located in Mullumbimby in the subtropical northern New South Wales hinterland. I talk with architect Michael Leung, the director of Balanced Earth Architects, who will share the inside story on his Sky Farm project.

Michael discusses the key design considerations, materials and products for a healthy home.

RATING 

And finally today, if you're enjoying my podcasts, I would love it if you would leave me a review or a star rating. To help others find the show, head over to www.ratethispodcast.com/renovationcollaborative  and follow the simple instructions.

RESOURCE LINKS

ROBERTSON ARCHITECTS - Project Page (images)

https://www.robertsonarchitects.co.nz/projects-1/bell-house

PROJECT INFO

ProClima external building wrap https://proclima.co.nz/products/weathertightness-systems/solitex-extasana

Neuffer Windows https://www.neuffer-windows.co.nz/

Luna Wood https://lunawood.com/

Rubio Monocoat https://rubiomonocoat.com.au/

Evolution Hardwax oil https://www.whittlewaxes.com.au/collections/hardwax-oils

OTHER INFO

ROBERTSON ARCHITECTS BLOG – State House to Passive House

https://www.robertsonarchitects.co.nz/blog/categories/residential

GET IN TOUCH

If you've got any comments or questions or there's any topic you'd like to know more about, please send me an email at [email protected].