Hi,

I have just come back from attending a pre fab modular home fair in China and came across these guys - www.ecoloo.eu They are a European company and it seems like a fantastic product. It may pay to contact them for some info. Cheers Isabelle.

When we had our sola60 hot water panel fitted with electric backup, we were told that a thermostat could not be fitted to the element cos of the panel.

In 6yrs, we have replaced blown elements every 10-12 months - the plumber is puzzled about why the elements are working so hard - could it be because the element is constantly working? Is it correct that a thermostat should not be fitted? Thanks.

I can only speak to my own experiences but we've used trickle vents in two builds now and found them to be very worthwhile. Like your design, our current house has very little roof space which could not easily accomodate a true HRV system (more on that in a minute). So instead we took the passive route and put trickle vents in every room except those that are purely south facing (only a bathroom and WC), and we leave them open for 8-9 months of the year, even in windy Wellington. The bottom line is we have no trouble maintaining very comfortable temperatures with very little heating in a highly insulated house, and the interior never gets stuffy.

On the HRV issue.. I did look at the following wall mounted units (imported from the UK) but couldn't quite stretch the budget: http://woodman.co.nz/vent1.htm

We were planning to install one in the garage (as that was centrally located in our L-shaped design) and run hard-pvc slimline ducting through our limited ceiling space from there. Good luck!

I personally hope Magroc SIPS will become more mainstream soon. Looks very promising and I would build a house with it as soon as all the details are worked out. Just don't want to be the guinea pig for a first time builder.

Thanks for your thoughts, and well done on achieving over half a century of oxygen supplies. I'm not quite there yet, but plan to continue breathing our atmosphere for the foreseeable future!
Will keep looking at the maths for the cost / energy / comfort benefits of the different systems.
Thanks again.

Thanks Nikoftime, may I ask who supplied your mechanical ventilation, and did you have heat recovery? How have you found the temperature in our house, is it even and draught free? Also, do you have gaps to the outside world e.g. Range hood extractor fan, catflap etc.
I have had a lovely chat with Grant from Fantech who supplies passive house MHRV, but we have another local vent shop that provides Moisture Master and Smartvent and I'm wondering if that is in the same league?
The conversation continues!
Thanks so much for your time reading this, much appreciated.

We have a sola60 hot water panel, and recently, the pump has been oscillating on and off every 10-20 seconds, mainly at night, or when the sun isn't shining.
I believe there are lots of plumbing reasons for short cycling, but I have no expert knowledge of either these, or other causes that might be related to electrics, or the sensors that tell the pump when the panel is 9 deg hotter than the tank etc.

If anyone has any suggestions I would be most grateful. And as Sola60 seems to have disappeared, do I call a plumber, an electrician, or someone else to help get it sorted? Thanks.

JK, I think that’s reasonable solution for a backup heating plan and in some situations we would recommend this to clients. In this case we have opted to put the money into a fireplace for the house which can be used for back up heating if there are extreme cold snaps during winter, also gives a nice ambience to the house. So, I guess this is also a juggling act between economics and performance.
There was a lot time spent on the solar analysis of the project and working out exactly when and where the winter sun will enter the house and leave it; this has driven the design of the project in all details. Basically from later March to early September the concrete slabs and precast walls will be bathed in sunlight, this is what we are banking on to warm the house and regulate temperatures.

these guys look like they could help:
http://www.fantech.com.au/Default.aspx

offices in Wellington, Christchurch and Auckland

Damper or Draft Blocker is probably a better term than baffle.

We have almost completed a complete renovation of our main bathroom. I installed a very good exhaust fan from hometech. I do notice a draft of cold air, especially in the southerly breeze.

I found this baffle online
http://www.batticdoor.co/bathfandraftblocker.html

Do any companies in NZ supply anything like this?

I agree win by having a great product, and contrubute to the improvement of the housing stock in NZ, not by bleating on about nonsense.

But that's the whole point of the codemark process isn't it? I've been reading the rules around codemarks http://www.abcb.gov.au/en/product-certification/codemark and they don't appear to be the shonky organisation you make out. Far from it judging by their website.

BEAL's website states that they "will soon become accredited to offer product certification" - what is misleading about that if that is what is happening?

Why single out and attack one company that you say is going through this certification process when judging by the very low number of certificates issued the vast majority of the suppliers to the building industry in New Zealand and Australia don't have certification for their materials? I'm sure you could analyse and criticise any process by any company, why pick on this one? Would you be brave enough to make similar accusations about Fletchers or Carters or Hardies? Or would the size of their legal teams budgets put you off?

I don't care what the product is, I'm totally sick of people who are probably competitors slagging new products off like this. Use it or don't use it, but don't try and scare other people off it over minor technicalities on foreign web sites.

o(0OO0)o,

I share your sentiments – the politics of who is ripping of whom is not relevant here.
Here is some practical advice for those of you unsure about MgO board.

Be warned - there are many different quality boards available out of China.
One sample (B) I hydroscopic tested has the absorbency of chalk. This results in the board absorbing atmospheric moisture when the humidity is above 60%, resulting in the plaster jointing compound and the priming paint not bonding to the board. It remains permanently ‘damp’.

A MagRoc (A) sample when completely immersed in water for 24 hours, has an absorbency of 15% - similar to Hardiflex but is stronger, more ductile, and more fire resistant so in my opinion, should be considered superior to Aqualine Gibralta Board interior and Hardiflex exterior as sheathing.

It is very easy to accurately machine and the dust is more granular rather than the fine dust from silica compounds as found in other products – no dust is safe but this is safer than most others.

As a bracing unit it is comparable to plywood, but is rot proof, has superior stability and is true in plane. It is hard to fault, so I have specified it for a residential design in earthquake prone Christchurch.

I am very impressed with MagRoc and hope that it will soon be available nationwide – what are you doing about sourcing this Bunnings?

'Hello 'justchecking'

A quote from Dean Buckeridge -
"It has been tested here in New Zealand at BEAL in Wellington and is about to receive the first CodeMark under the new joint Australian and New Zealand Standards Authority – the highest level of product assurance available".

Now it appears to me that the testing has been completed but they are still awaiting the actual certification - so as a designer, I will accept this assurance but maybe the Local approving authority might not accept just yet. As it will take some time to reach the consent stage I will proceed on that understanding rather than add in more delay.

Rex

Hi Sarah
Can I suggest you go have a look around the american website...
http://www.greenbuildingadvisor.com
They have vast resources and knowledge. You may need to pose your question to them, don't forget to emphasize that we are in NZ. (where else would you be!)

My point was that Magroc doesn't currently have CodeMark for NZ or Australia. They seem to think that the issuing of the certificate is such a forgone conclusion that they can ignore the rules of the issuing body and claim it in advance. What's the value in their CodeMark certificate if and when they get it if they treat the rules with such disrespect? What's the value in their Appraisal if their issuing body BEAL has been making preemptive claims of CodeMark authorization status for the past year. Presumably it is not BEAL that is going to be issuing this certificate that they value so much.

The relevance of the Canadian connection is that NZ companies infamously imported the leaky EIFS building problems from Canada in the mistaken belief that their systems would work in our temperate climate whist at the same time substituting flashing's with gunk from a tube etc.

Earlier attempts to introduce North American MgO SIP systems to Canada failed because since their leaky homes fiasco Canadian regulators are much more particular about traceable testing and preventing product substitution.

Can you not see the irony in using a NZ certificate, that they don't even have yet, to try to re-introduce the products into Canada before there is any significant construction history in NZ and Australia?

Give new products and systems a chance by all means but at least learn from our past mistakes and ask the hard questions. Ask to see the reports.

Meant to say the hot water heat pump controls could divert warm water to the slab when necessary.

JK

Is the internal temperature of the house designed to stay reasonable all year round without even minimal energy fed into the floor via pipes in the slab? I can't see how it will.
I'm not deriding anything. However a polished concrete slab below 20c is not that pleasant and I don't think it will stay above this right through winter.
Pipes in the slab and controls on the hot water heat pump would resolve any doubts without huge cost.

JK

Hi Nickoftime, Thanks for your question. Yes, you are right; there will some minor thermal bridging at the rib raft beam areas. How much we loose, I’m unsure of. However it’s going to be minimal and won’t impact on the performance of the house.
The choice of foundation is driven by economics and performance ;- ) so its balance between these factors I think.

Do the ribs act as a thermal bridge thus reducing that excellent R8 value?

Hello Russell,

This subject was covered under 'Treatments' (select any post with that heading).

You may find some of the answers there - regards Rex

Rib Raft Foundation system for Coatesville being laid. 300mm thick polystyrene pods form the basis of the insulated platform and Rib Raft. We expect to achieve an R value of 8 with the polystyrene pods and the 140mm concrete topping over will further increase this. This achieves a super high insulation value, keeping all that radiant energy in the slab where we need it.

I followed your link to the Australian codemark. It's only for board and not SIPs panels and only valid in Australia.

What's the big deal about what happens in Canada and why is it relevant to this forum? If the product has got a codemark for New Zealand then that's what is relevant here. You obviously have some axe to grind.

I've been reading these posts for a long time now and it really annoys me that Ecobob readers whine endlessly about how poor the standard of construction is here, but as soon as somebody offers anything better there's too many of you who can't wait to tear it down before it has a chance.

As far as the regulations are concerned you simply need to have the prescribed opening windows.

There are going to be two reasons to ventilate, moisture control and adequate fresh air for habitation.

If you want a simple prescription for moisture control, it might go like this...extraction in rooms where excess moisture can be generated ie kitchen, bathroom and perhaps laundry (you would need one way vents from the ducting to the outside otherwise your airtightness is affected) and venting of the house each day to remove general moisture build up.

The theory behind venting for moisture reasons goes like this, for a winter situation...suppose the inside and outside humidity is 80%, the outside air will be colder so if you open up the house to get an air change the colder air from outside will warm due to the thermal mass of the house, and it's relative humidity will drop so you now have air with lower humidity ie you have removed moisture from the house.

This leaves the question of air for habitation. I haven't researched this (but have kept myself supplied with oxygen for half a century) and I suspect the overnight requirement is relatively low. You could leave a window ajar to suit or have a trickle vent or have an exhaust or supply fan (perhaps one of the wet area fans) that can be set to a particular air flow rate. The later is available overseas but not sure of availability in NZ.

Having an airtight house and then doing something like having windows ajar may seem crazy but, firstly, there are other reasons for airtightness such as reducing moisture in walls and thermal improvements in same, but you need to compare the effect of that open window versus the heat lost via a mechanical ventilation system.

My understanding is that in mild climates the thermal gains of MHRV are marginal when compared to the cost. It really depends on how you want to live in the house, a more automated approach or taking care of a few things yourself.

Hi Sarah,
Excellent questions. I am really pleased someone has raised these questions as I have thought the same thing myself. The option that I chose was mechanical ventilation BUT I would be very interested to hear the Passive solar experts advice on this one.
As for no loft space, I understand it is possible to put the vent ducts in the floor slab although you would have to have a heat exchanger unit tucked away somewhere.
The choice between active (controlled) and passive ventilation seems to be one of the major differences between passive house and passive solar. It seems to me that the level of ventilation on a passive solar (natural ventilation) would often be too little or too much depending on how windy it is