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SUPERHOME Seminar – Wanaka Mitre10

March 13 @ 6:30 pm - 8:30 pm

Session 5 – Blink and Your House is Up

WHERE: Mitre10 Wanaka, 35 Plantation Road, Wanaka

WHEN: Tuesday, 13 March 2018


PRESENTER(S): Michael Sly (NZSIP), Henry Edney (MaxRaft) and Dale Smith (Sanctuary Building Supply Group – Siga)


If you’ve been to any of our monthly talks, you’ve have picked key concepts for designing and building a high performance home; elimination of thermal bridges, high performance windows and doors, the right membranes and tapes for airtightness and moisture control, higher levels of insulation, continuous insulation around your home.

We’ve talked about high performance windows and doors back in December, but now we’re looking into a couple of more contemporary construction options, the insulated concrete slab with side insulation and the use of Structured Insulated Panels or SIPs.

So, “Blink and your house is Up”, we’re kidding right; no actually we’re not.  NZSIPs are a new company making panels in Cromwell and they’re bringing a building on a trailer to Wanaka Mitre10 and you can see how you can put a house up in a couple days (Home Construction Video: https://www.youtube.com/watch?v=zrBJBKOSzZE).  SIP built homes are quicker to put up so the lower labour costs with other savings and higher material materials compensate for each other, but because the panels are built in a factory the quality control is assured and they come delivered with an exterior membrane, so it keeps out the moisture, so you can get on with the ‘first fit’ quicker.

Why should you look at constructing with SIPs rather than timber frame and conventional fibreglass insulation?

Whilst you can build a high performance home with various products and construction methods, SIPs have a number of fundamental advantages:

  • Faster to Build – NZSIP estimate about 55% faster as there’s no special tools needed, less on site bracing is needed during construction and the panels are pre-fabricated off site in a quality controlled factory
  • Less Waste – No cutting or off-cuts as the home design goes through a panel design stage to ensure the panels are sized for the build and simply erected on site.
  • Structural Shell means Stronger – There is essentially double the bracing given the use of the sheets of OSB or Plyboard, so that they will be up to 5 times stronger.
  • High insulation values – higher initial insulation values provided and more critically there’s no ‘sag’ with batts over time and the corresponding drop in performance over time. In a typical domestic timber frame building a minimum of 5% of the walls and 6% of a pitched roof will be uninsulated, such that the insulation performance of the timber and batts method in reality is much lower than what’s stated on the packet, unlike SIP insulation.
  • Equivalent cost – NZSIP panels with better insulation performance, airtightness and reduced thermal bridges inherent in the use of a SIP are equivalent to 140mm stick framing with R3.6 batts.
  • Airtightness – With SIPs you inherently have fewer joins involved and the OSB is an airtight product.
  • More Space – Roof SIPs enable you to use the open roof space to live in as a second floor rather than a roof of trusses.
  • Healthier and Safer – the products are often fire rated and water resistant, but also are mould and insect proof.

Note: You’ll need to check your builder knows how to build with SIPs otherwise they’ll be learning on your job and it’s going to take potentially longer (and worse for your budget) than a stick and batts approach.

NZSIPs have the following features:

By comparison to the standard 90mm framing used in most New Zealand homes, the standard 90mm frame with nogs has about 16% thermal bridging from the studs and nogs meaning that heat can simply escape from the building through these points.  Something completely avoided by the continuous layer of insulation used in SIPs.

If you don’t know MaxRaft then you should, they build a concrete slab poured on a raft of insulation that achieves more than three times the building code, i.e. R4.5 rather than R1.3.  A no brainer if you have underfloor heating because otherwise you’ll be paying to heat up your garden not just your home.

For a really great video on how MaxRaft install a well-insulated concrete slab, please watch:


How much insulation is enough in a Superhome compared with the NZ Building Code?

A guide to building a Superhome – Insulation

An alternative to simply aiming for a level of insulation, you can have the performance of your new home assessed from the plans.  Please contact one of our earlier presenters, Jessica Eyers at Hiberna Limited if you want to do this.  By doing the assessment you may re-balance the insulation between roof to walls or you might need simply less insulation than you think.  His PassivHaus Lite assessment may not only save you money on insulation, but give you invaluable information about building orientation, shading, position and size of windows, thermal bridges that will leak heat, etc.

If you don’t know MaxRaft then you should, they build a concrete slab poured on a raft of insulation that achieves more than three times the building code.  A no brainer if you have underfloor heating because otherwise you’ll be paying to heat up your garden not just your home.

For a really great video on how MaxRaft install a well-insulated concrete slab, please watch:


These need to be brought together with the right recipe, but these are building solutions that address many of these together.

We’re also joined by a third presenter you’ll have heard from before, Dale Smith.  Dale joins us again to talk about airtightness, and some very practical tasks too; doing some taping and demonstrating how we test for airtightness.  So even if you decide not to use MaxRaft or SIP construction methods, you may want to get in touch with Dale to assess your partially constructed home as to how airtight it is, how many gaps are there around windows, doors or other joins that would be quickly taped up and thereby boast the efficiency of your home to keep you warm in winter.

The airtightness test is done using a blower door that pressurises your home and measures how many air changes there are per hour.  You test the plumbing works, the electrics work, why not test how the building structure performs for airtightness?  Doesn’t make sense heating up that air in your lounge, bedrooms, kitchen and let it leak out through the gaps.


FEEDBACK – If you have enjoyed our Superhome Movement Talks here at Mitre10, please let us know as we’re working on a whole series of new talks for 2018.


  • Interior Design
  • “Interior Design Basics and Saving you money: We’re joined by a local Interior Designer, Lighting Designer and Appliance Manufacturer to help explain what’s involved in developing incredible interior and lighting designs (lighting: uses 10% of your home’s energy load) for your new home with appliances that are fantastic to use, but also save you money on your electricity bill.  What are the fundamentals of Interior Design and how to select the best appliances (appliances: uses 29% of your home’s energy load) for your new home are topics we cover at this Superhome Movement Talk on Interior and Lighting Design.”
  • Garden Design
  • “New Garden Design and Native Planting for Wanaka and Surrounding Areas: We’re joined by a local Garden Designer and Native Plant Nursery Representative to help explain what’s involved in developing an incredible garden for your new home with plants that will thrive here in Wanaka and give decades of joy.  With the warm summers, cold winters with frosts, strong winds at the equinox and warming climate our experts share their knowledge of garden design and plant selection that is complimentary to your Superhome, consume less water and make a really positive contribution to the beautiful place we live in.”
  • Real Estate, Property Valuation and Eco Building Market Trends in Wanaka
  • “The Real Estate Market and Eco homes: We’re joined by a local Real Estate Agent to help explain what value the real estate market and prospective purchasers or investors place currently and potentially in the future on homes with greater levels of energy efficiency, comfort or health including solar PV, insulation or building orientation for solar gains.  We explain and discuss whether your property is worth more when you invest up front on better design and more sustainable/energy efficient products.”
  • Building Consent
  • “The Hitchhikers Guide to Building Consent – Don’t Panic: We’re joined by a Planner from QLDC to help explain what’s involved in working with the council to ensure your new dream home or renovation is structurally sound, stands up to the weather and is fire safe.  Makes sense, you bet !  We share some do’s and don’ts that will make it a whole lot easier; getting it right first time is going to save you money, give you peace of mind and make sure you can enjoy your home for decades to come.”
  • Net Zero Design and Building – What does this mean? (August’18)
    • “Latest thinking in Sustainable Design and Building: We are joined by Matt Fordham from Evident to help explain the thinking behind New Zealand’s first Net Zero home, what Net Zero means and how balancing what power your home uses and what power it generates means no power bills at all.”  

 Sustainability – Smart use of Water and saving money on Building Waste (May’18)

    • “Using water wisely”: Mark Pfaff from AloAqua talks about rain water and grey water harvesting. Did you know using your grey water on gardens, flushing toilets and washing clothes can save 40%.  Talking about waste we are also joined by local legend from Waste Busters, Bis (Recycling Manager) to explain just how much waste is produced from building a 3 bedroom house (about 2 tonnes) and of course what we can drop off at Waste Busters and have recycled.












March 13
6:30 pm - 8:30 pm
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