Architects, designers, builders, here?

[Winston001]

straw bale interior, plastered

Like your ideas except not sure about straw bales. Mouses like them. As do insects. As does water...and water always gets in.

I'm merely a layman but always thought 200-300mm wide earth/mud/cement bricks made sense. Still need bracing, and battens for an airgap and external cladding. Double brick with an air space would be fine? Solid.

[Winston001]

Damn you Cola, you've got my mind working. One inspired example of thermal mass I saw in a book was in a harsh cold North American climate. Triple glazed windows. In the winter, clear 2m acrylic tubes 300mm wide were stood in the windows. Filled with different coloured water, they soaked up the sun and radiated warmth at night. They still let the light in and the colours made a kind of stained glass effect.

Stunning. And very clever.

[Spearfish]

Like your ideas except not sure about straw bales. Mouses like them. As do insects. As does water...and water always gets in.

I'm merely a layman but always thought 200-300mm wide earth/mud/cement bricks made sense. Still need bracing, and battens for an airgap and external cladding. Double brick with an air space would be fine? Solid.

Yeah your right, on top of that there is the threat of electrical faults and fire.

The tilt slab concept makes a waterproof concrete tank the shape of a house.

[The Pastor]

if i wanted to build a green house, i'd make it out of shipping containers. (recycling and all that bs)

http://green.yahoo.com/blog/daily_gr...er-houses.html

[Swoop]

Yes but full double glazing is assumed and (I thought) required these days anyway.

A confusing area. Compulsory double glazing throughout NZ now but repair work can be done to existing house standard.
New extensions could go either way, dependant on the council authority and their policy. They may insist on a new extension having double glazing even though the rest of the house is single glazed.

[Brett]

hyjoist are actually very economical way to get good floor spans and quality.The new 3604 is out and timber spans have decreased again I think.we use gluelams etc because a lot of "normal stuff cant be done with "normal msg8"(eg timber lintels,rafters joists etc)

Yeah, we used posi-struts in a few areas in our house recently built. Still opted for steel in high stress areas. Rather spend the $$ than have the issues associated with an under braced/engineered design.

[Brett]

tilt slab structure including roof
double glazed windows
straw bale interior, plastered
underfloor heating
stream for a small hydro (big enough to run a decent man cave)
grow your veg and sell the surplus for your grains
cow, goat, pig, for milk, meat etc
change the bike and car to diesel or electric if your not doing high miles
home brew diesel

then
Plan a bike trip around the word on a bike of your choice with your savings...

As odd as it sounds, tilt slab CAN be a very good alternative to conventional house construction. I plan on having a crack at one next year for a spec house.

[Winston001]

The tilt slab concept makes a waterproof concrete tank the shape of a house.

This interests me because I've been thinking about simple house design lately. Partly because I'm involved with Habitat for Humanity, partly because of the leaky homes debacle, and partly because of the problems of modern homes in the earthquake.

I understand there is some sort of lightweight concrete which can be used for tilt-slab. Is it porous, and is it strong enough?

[Ocean1]

A confusing area. Compulsory double glazing throughout NZ now

Fully phased in already? I thought it was still just the south and central north...

This interests me because I've been thinking about simple house design lately. Partly because I'm involved with Habitat for Humanity, partly because of the leaky homes debacle, and partly because of the problems of modern homes in the earthquake.

I understand there is some sort of lightweight concrete which can be used for tilt-slab. Is it porous, and is it strong enough?

If I ever build another house, (and, if I do stay well the fuck out of the way 'cause the battle with the many and various regulating authorities will be bloody)... where was I?... Ah yes... it'll be predominantly concrete. It'll probably be a mixture of standard tilt-slab exterior walls with some sort of facade over an air gap/cavity and solid aerated concrete interior walls.

Haven't come across a good lightweight naturally insulated roofing material yet. At least not a commercially available one.

[Spearfish]

This interests me because I've been thinking about simple house design lately. Partly because I'm involved with Habitat for Humanity, partly because of the leaky homes debacle, and partly because of the problems of modern homes in the earthquake.

I understand there is some sort of lightweight concrete which can be used for tilt-slab. Is it porous, and is it strong enough?

I'm not sure about the lightweight concrete part.
The process I watched was basically as follows
almost convention concrete floor was laid with a detail around the edge for the wall panels.
Once the floor was hard enough they laid out what looked like 100x100 steel angle over black plastic sheet to form the panels boxing.
any openings were formed the same way.
Steel mesh was tied in with other rods in various places (less steel was used than I thought would have been
2 domed things for lifting were placed and some threaded sockets
Some officious looking types ticked some boxes then they poured it like a floor but using a concrete vibrator.
they made the next section on the top of the first.
the gable ends were formed as part of the end walls.
they left it for about 3 or 4 weeks to cure I guess
A crane turned up with a truck load of acrrow props fitted with pivoting ends.
The panels were stood in a day and supported by the props screwed into the threaded sockets.
The outside was plastered the inside was gibed over battens.

The details of the floor or how the panels were joined I didn't see unfortunately.

[Swoop]

Fully phased in already? I thought it was still just the south and central north...

The changes are being progressively applied across the country during 2008. They apply now in zone 3 (the South Island, and the North Island's central plateau). They'll apply in zone 2 from 30 June 2008 and in zone 1 from 30 September 2008.

[Ocean1]

The changes are being progressively applied across the country during 2008. They apply now in zone 3 (the South Island, and the North Island's central plateau). They'll apply in zone 2 from 30 June 2008 and in zone 1 from 30 September 2008.

Classic.

"we're from the government and we're here to help."

About $4k extra on the cost of a house. $4k very few people chose to spend left to their own devices.

And they wonder why houses are unaffordable...

[flyingcrocodile46]

Agreed. We've been building dwellings for 6000 years designed for the local climate and land. Many houses last for hundreds of years which begs the question - why do ours fall to pieces??


Yes but full double glazing is assumed and (I thought) required these days anyway.

Double glazing isn't mandatory anywhere in NZ. It is only one part of one Acceptable Solution to NZBC compliance.

We have only been building here in NZ for approx 200 years. Our weather/environmental conditions are somewhat unique in the world and is problematic in respect to propagation of Molds and Fungi which eat away at cellulose fibre materials such as timber.

As opposed to many countries who build structures and clad in stone, we mostly use timber structure and cheaper cladding systems. Mostly we don't build in stone/brick because unlike a lot of the world we live in a earthquake zone and stone/brick can't be relied on to not collapse (in mild or moderate earthquakes) unless it is secured to a braced structure (which is typically timber here in NZ).

I'm merely a layman but always thought 200-300mm wide earth/mud/cement bricks made sense. Still need bracing, and battens for an airgap and external cladding. Double brick with an air space would be fine? Solid.

The NZBC allows construction of earth brick homes as an Acceptable Solution (can't be refused consent or CCC as long as it is constructed in accordance with NZS 4299 Earth "buildings not requiring specific design"). Cavities and exterior cladding are not required as long as the bricks meet the Standards erodibility/eave width blah, blah!.... "Table 2.2 – Site specific building limiting erodibility indices for different wind zones, wall exposures, eaves heights and widths in areas with up to 2000 mm per year average rainfallrequirements"

A confusing area. Compulsory double glazing throughout NZ now but repair work can be done to existing house standard.
New extensions could go either way, dependant on the council authority and their policy. They may insist on a new extension having double glazing even though the rest of the house is single glazed.

Double glazing is not compulsory and often isn't even required in most areas in NZ (and sometimes even in Invergiggle).
The NZBC H1 Energy Efficiency objectives, performance and functional requirements are based around limiting energy used to heat houses rather than setting minimum insulation requirements. Satisfaction of this objective is frequently demonstrated by the Calculation Method and sometimes by the Modeling Method without use of double glazing. For instance if you triple the insulation value of your walls, floor and roof Or your construction design and materials create sufficient mass as a heat sink and you only have a few small windows your energy consumption is stuff all (which is the NZBC objective). Most people don't understand the Calculation and Modeling Methods so choose to use the Schedule Method which stipulates the minimum R values of insulation to be used in walls, floors, roofs and windows (and these are the requirements that vary between zones) However that is their choice. It isn't mandatory.

As for additions and alterations, it rather depends on the size of the work area in respect to the size of the existing house, but basically speaking a sizable addition should be assessed as stand alone (if practical i.e a separate wing) other wise the work should (according to Section 112 of the Building Act 2004) be assessed as being required to "perform to the same or greater extent than previously".

I understand there is some sort of lightweight concrete which can be used for tilt-slab. Is it porous, and is it strong enough?

Yes definitely, and maybe (Depend on whether you want to use it as a structural member and the loadings involved).

The details of the floor or how the panels were joined I didn't see unfortunately.

In Precast and tilt panel the joins are predominantly reliant on only one or two lines of sealant to keep the weather out. (generally less consequence of damage to concrete structures)

[marty]

In terms of a durable interior lining, plywood is a good option, but to be able to get a nice finish you need to use high grade stuff with a nice surface finish which is not even close to cheap when compared to plasterboard. A good alternative is Elephant board (they do a multiboard which is more dense than standard boards like British Plasterboard or std GIB and is very cost effective. Also usually has a better/finer paper lining so the paint finish is better). Another option would be tongue and groove timber that you slot together. Can look really smart when painted, especially if the rest of the house is kind of sparse, and is very durable. Have you considered building the whole thing out of masonry blocks with a smooth plaster finish to the inside walls?

Sounds like you are after something practical and simple but sensible in its design for energy maximisation and limiting heat loss. I think that you budgeted figures will be plenty to achieve this.

ply can be expensive up front, but it's a single handle item (2 if you seal it) as opposed to gibbing, which needs 3 or 4 visits per sheet, super-accurate framing to look good, and experience (read:$$$$) spent to get a good paint-finish

[Brett]

ply can be expensive up front, but it's a single handle item (2 if you seal it) as opposed to gibbing, which needs 3 or 4 visits per sheet, super-accurate framing to look good, and experience (read:$$$$) spent to get a good paint-finish

Yeah, valid point on this.