5 Star & Timber Floors - the rules are changing...

Ed Perry · May 09, 2007 11:57 pm

ausdesign

As Ed has said - in Victoria timber floored homes [ on bearers & joists] are only required to attain a 4 Star rating level - to be revised on August 31.
To presume that homes with timber floors will require double glazing is a fallacy

Depending upon the site slope & the soil type, a timber floored home [with insulation] can often be more economical to build than a concrete slab floor, and also have a higher thermal value.

Although the overall thermal performance of the envelope of a home is by no means as simplistic as this, the presumtion or inference that in all situations timber floored homes are less thermally efficient is wrong.

It is for good reason that the HIA has been lobbying for 2 years against the imposition of 5 Star on timber floored dwellings and that is that they do rate worse than a slab.

Windows are the major energy leak in any home. This is evidenced by the fact that in the year 2000 the 2m x 1.8m window was 32% of total window and door demand in new homes - but today it is not in the top 5 windows. Why? Because design has been compromised by the 5 Star demands causing windows to get smaller - and that is in a predominantly slab construction. Timber floors make the matter worse. Of course you can build a 5 star rated home on stumps without double glazing... but you will pay more elsewhere and your design will need major compromise to achieve this. My argument is an economic one - double glazed windows (even better in a thermally efficient frame i.e. uPVC or thermally broken aluminium) are a good economic method of achieving 5 Star compliance with the least impact on house design. Plus double glazing adds comfort in temperature moderation and sound attenuation. Why avoid double glazing and substitute insulation when double glazing opens up so many more opportunities in design and comfort? In the USA & Europe it's a standard - it will be here soon. Ed

Yak_Chat · May 10, 2007 11:37 am

Hey Ed,
Yes double glazing is good, but bang for buck does it stack up that well?
Most states in OZ are not like Europe, OK Tassie and Alpine areas are a bit more like it, but generally we have hot summers and cool winters, not long freezing winters!!!

The probem that I see at present is the developers want the highest density of houses per block, and that is not the answer.!!!

I think the following article will have a much greater impact longer term, But it need a mandate to make it happen!!!

It is not all about making your house super efficent, it's more about being able to get some sun and breezes into the place to warm it up in winter - cool it in summer etc, all naturally via the sun adn wind, not via power gas or aircon inside a sealed up double glazed super insulated box.

Article follows:

Solar suburbs

Australian scientists are pioneering a world advance in city planning – entire suburbs that save energy and slash thousands of tonnes of greenhouse emissions through better layout.

Passive solar homes are all the rage among new home owners anxious to save money and live more sustainably – but their best intentions can be defeated by poor suburb design, says CRC Construction Innovation researcher Michael Ambrose.

“New building regulations are driving builders and home buyers towards more energy-efficient homes, but we’ve found that a poorly laid-out urban subdivision can counteract their best intentions, or cost them a lot more to achieve the desired energy efficiency,” Mr Ambrose explains.

“So we decided to see what could be done by better planning the entire subdivision, so the blocks have the best orientation and shape for energy-efficient buildings to be erected on them.”

The results were astonishing: a well-designed suburb can save its residents 20 per cent on their regular power bills and, if they use solar hot water, up to two thirds of their total power bills.

It would also reduce the greenhouse emissions of the typical Australian home by 700 kilos a year and, with solar hot water, by two tonnes a year!

The problem, says Mr Ambrose, is that suburban development is still driven by a desire for maximum ‘yield’ from the land by cramming as many blocks into it as possible, regardless of the costs that poor layout will then impose on builders and home owners – or the environment.

“There’s good evidence that by doing this, developers get less money for the land, because building costs are higher to achieve the required energy rating,” Mr Ambrose says.

“There’s a strong message from consumers today that they want to live in energy-efficient homes, and both builders and developers are now starting to get it.”

A well laid-out subdivision, where homes face the right way for passive solar heating and cooling, for solar hot water heaters, for natural light and to take advantage of local breezes, can collectively save millions of dollars to its residents in power bills – and thousands of tonnes of greenhouse gas emissions through reduced electricity use.

The concept is being trialled on new urban developments at Brookwater and Kelvin Grove, Brisbane, Queensland. If all the planned 8000 new homes at Brookwater were in a solar suburb, it would save 16,000 tonnes of greenhouse emissions a year – equal to taking 3000 cars off the roads every year, Mr Ambrose says.

“A typical Queensland subdivision can achieve a 3.5 star energy rating for the average home – but one laid out for energy saving can achieve 4 or 4.5 stars per home, simply through better planning.”

The bugbear is the narrow east-west block: even a well-designed energy-saver home may have trouble meeting its ratings on this, he adds. It will probably need extra insulation and blinds, more cooling and heating and use more power for hot water.

“In Queensland and the warmer States, the single biggest consumer of energy in the dwelling is for hot water heating. The use of solar hot water systems can shift up to 90 per cent of this energy need from fossil fuels to renewable energy. Integrating solar hot water into home design from the outset is one way builders and developers can contribute to huge reductions in energy use.”

According to Mr Dayan Jayasekera, Project Manager of Springfield Land Corporation, “The Brookwater JV is committed to helping builders and purchasers arrive at cost-effective and sustainable solutions to building at Brookwater, while at the same time taking on the stewardship of looking after the environment for generations to come. Our partnership with the Sustainable Subdivisions Project will help us meet that commitment.”

Besides solar orientation, the CRC team is exploring the use of suburban layout to take better advantage of cooling breezes in summer. Though there has been a lot of research into wind for power generation, little as yet is known about wind patterns in suburban areas and how they can best be used to reduce use of air conditioning.

Construction Innovation CEO Professor Keith Hampson says sustainability is at the heart of the future of Australia’s property and construction sector. “This project was the first in a series exploring a broad range of sustainability issues facing new subdivisions. By working closely with our partners, priorities are determined that enable us to target this research to industry needs. The important practical outcomes generated by the project will be shared with industry through publications and seminars,” he says.

Prof. Hampson says the research addresses two of the National Research Priorities – a sustainable Australia and frontier technologies to transform industry.

More information: 07 3864 9295

Ed Perry · May 12, 2007 11:45 am

Hi yak-chat,

You make me think too hard!!!

Bang for buck in terms of energy saving, double glazing? Sure - plugging the biggest leak in the envelope (windows & doors) can mean not spending so much on other insulation... I believe the economics are already there. But there is more to it than pure economics - or we would all have laminate bench tops in kitchens rather than granite or reconsituted stone. With double glazing it's letting light into the home with big windows rather than shrinking window sizes in single glazing, and it is comfort and resale value. In 2 years double glazing will be the norm.

Europe has many cimates - as do we and its a clear case of what works in Europe and the USA works here in the same climate zone.

Quote:

It is not all about making your house super efficent, it's more about being able to get some sun and breezes into the place to warm it up in winter - cool it in summer etc, all naturally via the sun adn wind, not via power gas or aircon inside a sealed up double glazed super insulated box.

It's really about choice - most people want windows and walls and most people want a comfortable temperature with minimum variation. And you cannot do that anywhere in Australia by trying to control natural sun and wind - what do you do when the sun isn't there or there is not even a breeze?

I think having an insulated home (I prefer home to box) incorporating some of the ideas you mention, (openable windows & doors to enjoy breezes, making best use of orientation) means that it should be possible to design a home in Australia with large double glazed windows that would have zero energy useage (for heating or cooling) and deliver the comfort we all expect. And that summer/winter scenario that everyone speaks of is very simplistic - temperature variations through the day (that's 24 hours) are enormous in any season - design to cope with that in an uninsulated home!!.

Ed

Yak_Chat · May 12, 2007 12:33 pm

Glad to help get the brain working Ed.

Agree,
Double glazing is something we should embrace.

SA only brought in the 5 star system in May 06. Yeah yeah, wind your clocks backwards 10 years - you've landed in Adelaide.
I used to live in QLD during Bjelkie days too so I'm used to that.....

But SA's 5 star system does not require slabs or suspended floors to be insulated if in Zone 5 which is Adelaide.
Maybe that will change for us too? I hope so....

But the main point I'm making is the ability to actually do something about the house/block orientation so you CAN maximize solar and breezes, which seems to have been primarily overlooked by the developers because the councils/Satet Govt's do not demand it.
(ie people have to make do with bad blocks and have a neighbour house wall 2 metres away, and they have difficulty, ie it costs more to build etc and NO sun can get into their desired north facing room without major hassles.
Make it too hard to do, and most people will shy away from it.
I remember when seat belts were not mandatory, and if we had them they were hard to adjust so lots of peope said, too bad, then they made them easy to adjust via retracters and people wear them etc

to the point that in Amercia the door closes the belt onto you - no choice. But they're not as smart as us are they

Back to double glazing,
I'm currently designing my own "double glazing system" as I have 3 x large aluminium sliding doors with glass panes either side of each door in my upstairs area (Which is a suspended timber floor above the original roof when they extended)

And this western facing wall is approx 75% glass + the northern wall I estimate is about 50% glass.

But there is no shade over any windows, no eves nothing!!! . :shock:

The rain comes in, sun heats the place up, vertical venetian drapes. Poor thermal gains ie timber floor, and heat losses big time.

But the main point I make it that when I looked at this place, I wanted the northerly aspect, and the other was that i liked how it was higher than my neighbours houses which lets the breezes through in summer (a raging gale at times due to our gully breeze effect at times)

And once I open up the doors (it can 45 degrees upstairs) it quickly cools down to a pleasant temp.
So far Autum is OK, but I do know I will need to stop my heat losses through the aluminium frames and glass before August gets here.

Double glazing system - Definiatly - With this view, natural light etc, why would want to block it out with dark curtains, small windows etc

Cheers and great chatting.

We are on the same track of thought.
Steve

Ed Perry · May 12, 2007 1:04 pm

100% agree Steve... it needs a big name builder to design a house that fits every orientation - because economics dictate small blocks with multiple orientation street frontage are the norm. And what sells houses?

1. Clever marketing (M/con)
2. Street appeal
3. Other stuff like bench tops

We need to combine street appeal with orientation choice, so the location of living zones would need to be flexible in the design so that windows can suit the orientation.

I think we need a section in the forum dedicated to this stuff - Eco Living... not just double glazed.

Anyhow see you there!

Ed

Ed Perry · May 13, 2007 9:58 am

Hi Steve,

Sorry I did not scroll down far enough so missed the rest... nice views, lots of glass...

I used to live in a 2 storey home and I can relate to this problem. The glass areas let in the radiant heat, then the convected heat comes up from below.

Would you get the house energy rated as a guide to what to do? Or would you could just go ahead and do what's sensible? I would think you need to stop the radiant heat in the ground floor too...

Looks like double glazing with low-E to the glass areas exposed to the sun.

Ed

Yak_Chat · May 14, 2007 12:23 pm

Yes intend to rate it before I change big ticket items, but there are obvious things, like sections of the ceiling is not insulated on the vertical sections that are internal walls o the other side, and I'll just do those now !! because I know they will work this winter and should have been done.
Re heat coming, up, I intend to block it off so that does not hapen unless I want it to, otherwise you're heating downstairs and it's overheating upstairs.
Cheers
Steve

wonderland · May 23, 2008 12:06 pm

Hi guys,
I just want to make sure that this new rule only applies to homes built on timber stumps right? If you have timber floors on a concrete slab, it doesnt apply right? I'm abit confused!
:oops:

Thanks.

kiwi056 · May 23, 2008 12:17 pm

wonderland

Hi guys,
I just want to make sure that this new rule only applies to homes built on timber stumps right? If you have timber floors on a concrete slab, it doesnt apply right? I'm abit confused!
:oops:

Thanks.

In your situation the slab is the floor and the timber is a floor covering.

wonderland · May 23, 2008 4:08 pm

Oh good, many thanks Kiwi :lol:

u9026a · Jun 09, 2008 11:09 pm

I used to live in Burwood, Melbourne. It gets cold, very cold. Double glazing shouldn't be an option, it should be stipulated in building regs. But this being Australia, 10 years or more behind Europe, it's not. Its quite sad really.

What do you reckon a 5* rating is worth here in comparison with Europe?

I guess its really all about money and petty short-term politics.

McKinnon · Mar 02, 2009 1:33 pm

The plans for my new house include a concrete slab, maybe thermacell or hebel, d.glazed windows, family room facing nth, solar hot water( I would love to go solar the whole way but Govt does not give incentive) and rainwater tanks.
It sounds like I will be 10 star, great warm in Winter and cooooool in Summer!

lambchoppa · Jul 06, 2009 8:15 pm

Yak_chat
Why don't you try masterwall (http://www.masterwall.com.au) or expol (http://www.expol.com.au) batts (polystyrene concertina style) or austral (http://www.australinsulation.com.au). These are easy to DIY (and I think about $10 / m2, on http://www.buybuildingsupplies.com.au) and will give you a good result. Easy to work with in a confined space.

Sorry ... in reference to your post a while ago about insulating timber sub floor.

Yak_Chat · Jul 06, 2009 10:11 pm

Thanks Lambchoppa, already done it with Polyester batts.
I prefer that over polystyrene due to VOC's - excepting for the installation method of polyester. :::

Cheers

ausdesign · Jul 07, 2009 6:22 pm

As an update, the FirstRate5 program appears to be 'kinder' to timber floors. This may be due to overall configuration but the last 4 ratings we've carried out did not require subfloor insulation to meet minimum requirements. - not that you should look at minimums but sometimes the pocket isn't bottomless.

McKinnon · Jul 13, 2009 12:27 pm

I am about to start building my dream house in Melb. Slab, nth facing, solar hot water and double glazed windows which are an absolute rip off in this country. I saw a company at the building show promoting triple glazed windows. Can someone please explain the benefit of these compared to double glazing.
Cheers

lambchoppa · Jul 13, 2009 12:39 pm

Triple glazing is simply more insulative than double glazing. I would not see the extra benefit in Melbourne (vs cost) assuming you good roof / wall insulation, adequate draught sealing. You would be better to go for double glazed, low-e argon fill double glazing, this is effectively the same U-value as triple glazing.

Yak_Chat · Jul 13, 2009 10:35 pm

Peter, what climate zones where those last 4 houses with the timber floors in?