In New Zealand, the hobbits have them

I was just catching up on your Psycho Sciences (write more!), and read in the one about passive smoking that "very few [Australian] houses have basements", versus houses here in the USA, where we usually do have basements which, as you say, serve as convenient radon-accumulators for householders in need of a higher cancer risk.

Why is this? Is Big Radon Detector Business conspiring with architects to maintain demand?


Some of the differences in dwelling styles between countries are purely cultural, with no very logical reasons either way. Then there are obvious ones like "our houses are made of stone, 'cos there's no bloody wood for 500 miles". And then there are others that make only a very small amount of sense, like the almost complete absence of European-style heat-retaining technologies in Australian houses. This creates the peculiar situation that although a Sydney winter is not unlike a northern-European summer, Sydneysiders spend more time being cold in winter than Finns do, because Sydney houses are usually poorly heated, draughty, and often surprisingly poorly insulated too.

(This applies to Katoomba, where I live, as well. Katoomba winters are still a joke by countries-where-it-snows standards, but overnight temperatures around freezing point are still quite common in winter, as are tourists from elsewhere in Australia gazing in surprise at the ice on their car windscreens and wondering what on earth to do about it. Yet many houses here are built no differently from houses in much warmer beach towns, and their occupants suffer accordingly.)

Many house-design differences have a quite simple rational basis, though. Like, here in Australia it's easy to find houses with flat, or only gently inclined, roofs. In countries where it snows in winter, there's pretty strong selective pressure...

Carport snow collapse
(Image source: Flickr user HoundCat)

...against people who choose to live under a flat roof. Here, not so much, and a flat roof is simple and cheap to build.

The snow/no-snow roof design holds for most countries. In very hot areas, a flat-roofed house can also be built to let you sit out on the roof in the breeze of an evening.

The basements/no-basements thing has a rational basis, too, which once again holds for a large number of countries.

Digging a big hole under a house is time-consuming and expensive, and asking for trouble from water seepage. If you want that much extra space in the building, and are not living in some godforsaken wasteland that's shaved flat by tornadoes every ten years, it's faster and cheaper to just build a taller house.

Unless it gets cold enough in the winter for the ground to freeze to a significant depth, and then warm enough in the summer for it to thaw again.

If that's the case, then "frost heave" (which, coincidentally, is yet another thing Matthias Wandel has had to deal with) will slowly push anything sitting in the freezing and thawing earth up into the air.

Frost heave makes shallow house foundations a terrible idea. So you have to dig a hole to put the foundations in, and you might as well make that hole into a basement while you're at it.

Some basement-equipped houses are built in places where frost heave never happens, for the abovementioned cultural reasons. But you generally find them in cold-winter locations.

In Australia, you usually have to build to minimise the effects of heat, not cold. This has given rise to the famous underground houses of Coober Pedy, and the much more common "Queenslander" house style...

Queenslander house
(Image source: Flickr user Crazy House Capers)

...where the house proper sits as much as a whole extra storey high on "stumps", to catch the breeze and keep Queensland's trillion species of house- and/or human-eating arthropods that much further away.

Psycho Science is a regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

18 Responses to “In New Zealand, the hobbits have them”

  1. cfuse Says:

    It doesn't help the cause of basements any that most of Sydney is sitting directly on sandstone (I cannot speak to the geology of other places here). Sure, you can cut into it, but that is expensive (and most of the time that is in the service of garaging vehicles).

    There's also the matter of flooding and fire, neither of which makes a basement anything more than a liability.

    We also don't really have anything like American attics.

    • wumpus Says:

      No attics?

      Attics have two purposes. First for storage, and probably more importantly to remove solar heating during the summer. You want a fan at each end for maximum air flow and removal of heat buildup.

      I did see some sunshades in a botanical garden in Arizona (Southern US desert area). They used strips of material to block the sun but allow rain down and head back up. Presumably this could be used above a roof.

  2. corinoco Says:

    As real live architect, I feel eminently qualified to comment.

    First of all - the 'Queenslander' is arguably Australia's earliest home-grown housing style - arguably because it isn't much different to anything you'll find between here, Hong Kong or Bangkok - in hot humid climates where flooding frequently happens *cough* Brisbane *cough* up on stilts is where you want to be. Pretty funny that in the past 20 years or so our housing styles have largely copied America - not even REAL America but TV America - and then we see a couple of billion dollars damage to housing for no good reason but faddish consumerism. Anyway, enough of that rant.

    One really big reasons for the almost total lack of basements in Australia up until the 60's - yep, that's right 1960 - is our soil.

    If you live in Australia, and are not right on a beach, have you ever tried to dig a hole deeper than about 30cm? Hard, isn't it? Thats because our average soil depth here is only 30cm, rather than the 2m or more most of the rest of the world enjoys. The First Nations knew this - which is why they 'buried' their dead by wrapping them in bark and putting them up a tree. You can't easily bury people here without a lot of work. Basements are VERY hard to dig, even today, because in most settled parts of Australia you go down 30cm, then hit about 15m of evil yucky clay. You can't build in clay, you HAVE to go down to rock unless you only want your house to last 10 years or so, so that means multi-story basements carparks are economically viable, but basement storage generally isn't.

    If we DID have basements, some areas would have the same radon issues the US has - anywhere that is a major volcanic region with basaltic rock would have problems. Mt.Wilson in the Blue Mountains is the closest volcanic province to Sydney, although there is a small vent near Rydalmere if my memory serves. The Whitsunday Islands are one of our largest volcanic provinces, but there aren't even many people living there, let alone building basements.

    Our house design, especially in the past 20 years, has been uniformly abysmal, right across the nation. In 25 years or so the McMansions that everyone spent 35 years paying off at the ludicrous prices we endure will be falling apart - construction standards are low enough to make China & India look good, and we have just found out in the past two weeks that our system of 'building inspectors' is utterly unreliable and corrupt to the core. I know - I work in the industry (or did until 4 months ago, when I quit for good)

    Apart from the Queenslander style, the best house style ever to be built here was the 'Sydney-School' style that arose in the late 50s as a blend between 50's US style and Nordic construction. Yes, for 20 glorious years we built houses the way they do in Northern Europe - with a concern for natural heating and cooling, using site-appropriate materials, and featuring modest but re-configurable spaces. The houses were very cheap to build compared to modern designs, and were tiny by today's ludicrous standards - but then we didn't need 6 bedrooms for 2 people, 3 car spaces, ensuites off the ensuites, walk-in-robes for the dog, bathrooms with 76" plasma screens, kitchens built out of finest Italian lagerstatten with 12 gas burners (just like they have on Master-Who-Wants-To-Be-A-Dickhead-Survivor-Chef!).

    Bitter? Me? No. I design supermarkets now. I feel morally and ethically pure compared to designing the 1,600sqm 'beach cottages' I was working on for most of the past 7 years.

    Comment bigger than the post? CHECK!

    • Henry Says:

      I'd really love to know why builders in Australia abandoned all sense. I grew up in a high-set Queenslander in a hot, central-Queensland town, and it was amazing how cool it was.

      I die a little inside every time I visit a housing estate and discover that the thermal design of every slightly dissimilar brick box consists of "throw an air conditioner in there". Why can't we have modern, thoughtfully designed houses anymore? I can't imagine the rich folk do much better, what with their northern-facing glass walls and complete lack of natural air circulation. But then I guess you can afford to run your air conditioner 300 days of the year.

      Oh and ceiling fans. Why the hell did they go out of fashion? probably 1/10 the power of a noisy, expensive aircon unit, and will keep you cool enough most of the time, especially if you house hasn't been designed by an idiot.

      • dan Says:

        the thermal design of every slightly dissimilar brick box consists of "throw an air conditioner in there"

        Yep - giant open-plan living/kitchen areas with huge windows facing west, for instance. Result: Apocalyptically huge electricity bills for air-conditioning an area larger than many whole houses twenty hours a day for six months per year.

        And some of those horrifying mazelike curly-streeted self-similar housing developments also come with a minimum permissible house size, just to make sure that nobody ever builds anything sensible there.

        • harald74 Says:

          I live in Norway, and where I live it can get down to -30C in the middle of the winter. A friend of mine studied in Australia, and I'm not sure I quite believed him when he told me that he had never frozen so much in his life during winter.

          Norwegian building code is quite strict regarding insulation. The new standard is 25 cm rockwool or equivalent in walls, and 30 in ceilings, I think. And balanced ventilation with heat recovery (I'm not sure what it's actually called in English) is mandatory for new housing. The new thing being experimented with is passive or zero-energy loss housing, which tries to do away with the need for extra heating altogether. Massive amounts of insulation and different heat retaining systems are the keys, illustrated by this poster from a Norwegian university.

          • TwoHedWlf Says:

            Yup, same over here in NZ. Poorly heated, poorly insulated houses combined with very damp weather makes temps around freezing feel MUCH colder than when it's a nice dry temp well below freezing.

          • James Says:

            When I came back to Australia after living in Canada for sixteen months, I felt rather foolish for the way I felt so cold during winter. The fact is that subtropical Australia doesn't bloody well get cold enough in the wintertime to keep us on the straight and narrow. That goes for our clothes as well as our houses.

            I too die a little inside when I see these god-awful housing developments going up along major arterial roads outside Melbourne (as far away as Pakenham, over an hour from the city!) and they are just fucking terrible even to someone like me who isn't an architect. No eaves for proper shading, undoubtedly no insulation and an AC unit, no thought for positioning because they're all off the shelf plans just thrown down willy-nilly, and no ceiling fans, of course.

            My parents' brick house has a ceiling fan. In fact, it has two now. They still haven't bought an AC unit to install. They've tried to retrofit some insulation since realising just how useful it is but there's only so much you can do with a house that's already been built unless you're willing to start ripping shit out and redoing it.

  3. Mohonri Says:

    An addendum to the point about digging basements--in my area, it doesn't actually take that long. My subdivision is one that was hit with the housing crash, and builders are only now starting to build on some of the empty lots. I noticed someone doing some survey work on one of the lots yesterday morning, and by mid afternoon, the basement foundation had been dug. Regarding expense, however, you're right--it does cost more money. The dirt has to go somewhere, and it's extra concrete, but the incremental cost per potentially-someday-finished square foot is quite low.

    Also, depending on the climate, the frost heave may not go down all that deep. It's about four feet in my area. So builders have the option of just digging deeper trenches for the foundation walls or digging a crawlspace, or doing some combination of those along with a basement. Many of the homes we looked at when moving into the area had foundations that were half crawl space and half basement.

    • Mayhem Says:

      Yep, my uncle has a place in Perth, and when he decided he needed a wine cellar, he just put a couple of meters of large culvert pipe on end in his garage, and started digging out the sand from the middle to sink it down below ground level. Took a few hours, but boom, instant basement.

      On the other hand the ever present sand makes for one heck of a gardening problem...

  4. Chazzozz Says:

    I used to wonder what was so great about Queenslanders...until I actually moved to Queensland. I live in one of the modern American-style bungalows that corinoco ranted about, and even though it's fully insulated I still find it hard to evenly cool in the summer. Reverse-cycle air conditioning can only reach so far, and it's certainly not practical or economical to put one in every room. A mate of mine lives in a Queenslander and it never ceases to amaze me how lovely and cool his place is all through the summertime, irrespective of how hot the weather is.

    Winter is marginally better. Here in Australia's other 'oomba' town night temperatures can often drop close to Katoomba's (daytime's a lot warmer, though). This is when a properly insulated house that sits flat on the ground works well. The mate's place is full of cold draughts and you need to huddle close to the wood heater in order to stay warm.

    On that note, I'll mention one other peculiar characteristic of Queenslanders: due to all that excellent ventilation if they ever catch fire they go up in flames amazingly quick. I'm also part of the local fire brigade and I've seen quite a few of them do this. No matter how quickly we arrive it's almost always just in time to save the stumps. If you live in a Queenslander then it's an excellent idea to be certain you have good fire insurance.

  5. david Says:

    Basements are by no means common everywhere in America. Here in the American south, where the frostline is usually no more than a few inches most houses since the 80s have been built "slab on grade" with no basement, and even before almost all houses were built with a few feet of crawlspace underneath, with basements usually only occurring in places where the house was conveniently built into a hillside.

    I can't speak for the west coast, but it seems like basements might be more trouble than they're worth in earthquake country.

    • wumpus Says:

      I grew up in a house just south of the Mason Dixon line. According to the neighbors, the basement had been blasted out. I can only assume it was already in the contract as houses in similar locations are on slab.

      There are also places like Florida. Dig a basement and you have an indoor well. (Oddly enough nearly everything on the coast from New Jersey to at least South Carolina is built on stilts. Jacksonville, Florida has apparently never heard of Hurricanes.

  6. TwoHedWlf Says:

    My parents house, in Alaska, didn't really have a basement even though I think the frost frost depth is 10 feet. Houses there are built to about 4 feet. Just needs to be deep enough that under a nice warm house the ground doesn't freeze.

    So it was basically a standard house sunk sunk half a story into the ground rather than a basement. Pretty common.

    • harald74 Says:

      It's the same where I live in Norway. The ground here is very, very rocky, so basements can be costly. Most modern houses are built on a slab, which is not very deep.

    • Stark Says:

      As a former denizen of Alaska (Fairbanks) I can say that the goal there is to dig deep enough to have the base of the house sitting in permafrost - which doesn't undergo the typical frost heave cycles as it stays nicely frozen all the time. As such it acts very much like bedrock. The typical half sunken level construction in Fairbanks gets the actual foundation down into the permafrost and anchored tightly against the frost heaves that do occur in the top 50-100cm of soil which does manage to thaw in the summer.

      True basements in permafrost country are fairly rare - digging out anything more than ~30cm deep into the permafrost is an exercise even backhoes have trouble with. The cost to do so is enormous and all you get for your trouble is a permanent walk in freezer which you have to insulate your upper floors from!

      As the summers get hotter and longer (due to climate change) and thus the average temperature rises across the Arctic the permafrost is shrinking - quickly. I have a friend who is a structural engineer in Alaska and he is already starting to see some structures with signs of frost heave damage due to the reduction in permafrost. It's gonna be rough ride for most of the homes built on permafrost over the next 30 years.

  7. arikol Says:

    I come from Iceland and currently live in Sweden. As a child I lived for a while in Australia, near Perth, and I can tell you that the winters there felt COLD. Of course, woolly underpants were less common there, but that's really the thing. Around here (the Nordics) we have insulation for our houses and for ourselves. That means that -25 isn't really so bad..

  8. J Says:

    Yeh, it's pretty crazy here in Perth - it doesn't get too cold, but it's really hard to heat, and then really, really hard to *keep warm*.

    I can sort of understand building dopey designs in the 80s, since electricity was as good as free back then (as with our house - if we actually put all the lightglobes into the available sockets, it'd be like living inside a Christmas tree all year round!), but some of the utterly stupid houses I've seen built in the past decade are beyond belief.

    There's just no excuse for not designing a house to take maximum advantage of positioning for warmth/cooling effects in the various seasons. And don't even get me started on the places that are built with aircon, but no insulation - what the hell are they thinking?

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