The Ecobob member's forum: where members discuss, discover and network all things green and eco.

Keyword Search

MgO & SIPs

MgO & SIPs

Posted 03 Oct '11 11:55 PM

Hi all,

To follow on from Steve’s recent posts on MgO I can confirm that there is going to be an MgO supplier in the NZ market in the near future, and the intention is to produce SIPs from a production plant in Christchurch.

I have been working with the people concerned for some time assisting in a technical and design capacity operating under a confidentiality agreement, so was not able to join in the discussion previously, but we have progressed to a point where we I can release a small amount of information to EcoBobers given the previous interest. Recently I have been offered a minor shareholding in the company which is really cool and I am very excited about so I need to first declare that I have that interest.

The company has an association with a North American MgO company that has been developing their product for over 10 years and have been building commercially in SIPs for 5, so there is a significant background of experience and international testing that we are able to draw upon.

The product is fully certified for use in North America and has begun the first stages of evaluation for NZ appraisals, and the intention on our part is to go on and have full CodeMark certification completed.

One of the things that we discovered early on is that there are many producers of MgO in China and the quality varies widely. MgO is not unlike concrete in that it is possible to produce very high quality concrete with careful production techniques, the right basic ingredients and additives, but you can also mix up some sand, cement and water in a wheelbarrow and call this concrete too. There has unfortunately been some low quality MgO distributed in the US for linings which has suffered cracking issues; a quick Google will find plenty of examples on forums. So the decision was to work with the best product and the people with the best track record that we can.

Good quality MgO is an amazing product. The finish is like fibrous plaster, the strength tests for nail pull out, shear strength etc. are remarkable and similar to plywood, but its moisture uptake is similar to fibre cement – i.e. very low. It is totally inert, won’t support mould growth, and doesn’t degrade when wet. Fire resistance is no issue, it’s also used to line furnaces. It has a low embodied energy content, is cut using standard wood working tools and the dust is not hazardous, and we are developing techniques to use offcuts as ancillary components and minimise waste . It is hard to find a down side to this product at all.

SIPs panels will be able to be manufactured in virtually any thickness, final R values will be announced when the product is launched, we have some options for the foam core that will affect this. The plan is that rather than sending out full panels we will build up complete wall and roof sections in the factory where we can work to engineering levels of precision as opposed to cutting on site where the tolerances are less stringent, that’s not to say that full panels won’t be available I’m sure on request.

Interestingly the North American construction detailing is not as rigorous around thermal bridging as I would like to see so we are addressing that locally with alternative options.

There will also be a range of supporting MgO products for soffit linings and trim etc. for people wanting to go the whole way in MgO, but we are not planning to enter into the general linings market for timber framed houses and compete there. Too big, the cost of supply and distribution of a house load of MgO sheets to every merchant in the country would be a huge draw on financial resources, and the competition would be expected to vigorously defend their established market.

Pricing at this stage is a long way from being confirmed. As Steve mentioned in his earlier posts the actual cost of getting the product into a container is reasonable, but it has been a real eye-opener to see the add on costs mount as the business plan develops, shipping

Re: MgO & SIPs

Posted 06 Oct '11 08:23 AM

Hello Dean,

Thanks for a comprehensive update.

I brought up Steve's stock of 8mm MgO board before he left for Oz, to test and use for wall / ceiling linings substituting for 10mm Aqualine.

After I install, I will post my experiences but note that the edges are slightly more fragile to handle than an equivilent thickness of fibrous plaster or 10mm Gib.Bd, but that characteristic should not to be construed as presenting any fixing limitations.


Re: MgO & SIPs

Posted 09 Oct '11 08:46 PM

Hi Rex, I would be very interested to hear how you get on.

It's interesting that you say the edges appear fragile, the samples that we have been working with appear to be anything but fragile and we have been looking at the possibility of profiling them for window reveals and trim.

The latest testing is achieving more than double the nail-head pull-through strength requirements for ASTM tests for both Fibre cement boards and Fibre reinforced MgO sheets, and flexural strength and shear bond strengths are 2 - 3.5 x minimum requirements so our experience is of a very robust product, more like fibre cement.

Are you talking about cut edges or the original sheet edges?


Re: MgO & SIPs

Posted 10 Oct '11 02:38 AM

Hello Dean,

You are right - MgO board specifications vary alarmingly and the material supplied to Steve was intended for SIP fabrication with a lower density than that to which I suspect you are comparing - Eg the usual specification density of a 2400x1200x8 sheet is about 27Kg where as my sheets are only 20Kg.

Steve recognised the more fragile nature of his stock and checked with me as to my intended use for ceiling lining before confirming that they would be suitable for that purpose and I am content I got the specification I paid for.

I am currently experimenting, by constructing a panel fence using two adhesive bonded 8mm MgO sheets, substituting for 12mm cement fibre sheets of 1200 x1200 in timber framed panels.

Will let you know of any construction idiosyncrasy and performance in a little while, but so far, I am singing the praise of MgO against cement fibre and Gib. Board even though my material is of a far lower specification than yours.


Re: MgO & SIPs

Posted 24 Nov '11 10:40 PM

Hi Rex,

How are you finding your MgO? We have our first stock container arriving in the next couple of weeks and if you are happy to receive it we would like to send you some sheets to compare with what you have.


Re: MgO & SIPs

Posted 24 Nov '11 11:24 PM

Hello Dean,

I would appreciate you sending me an A4 sample of 8mm-9mm by post as convenient, and I will machine the edge and report back on the comparison.

As metioned before, I except your sample to have a superior performance to my sheets. (A 'photo of my fence constucted from 2 laminated 8mm sheets is attatched).

Thanks - Rex

Re: MgO & SIPs

Posted 24 Nov '11 11:31 PM

Hello again Dean,

Good idea to give you my contact at - come back via email for my address please.

Thanks Rex

Post Your Own Comment