Gestalt said...

hi herry,

i think the idea of light colours and large overhangs is over rated. it's such a small part of things and in the end will leave you with a building that potentially is very cool but will freeze you in winter.

Yeah, our house is so cool in summer we haven't needed an air conditioner. We've been fairly lucky here compared with many other areas of Australia, I think the hottest we've had is a 36 degree day. But if we stay inside all day with the blinds down, you'd think it was only around mid 20s. I do wonder what it will be like in winter.

Herry said...



Yeah, our house is so cool in summer we haven't needed an air conditioner. We've been fairly lucky here compared with many other areas of Australia, I think the hottest we've had is a 36 degree day. But if we stay inside all day with the blinds down, you'd think it was only around mid 20s. I do wonder what it will be like in winter.

If it's too coold in winter, all you need to do is get some northerly sun in. If you have northerly windows with too much overhang try using patches of clear roofing over the windows. If you can calculate your sun angles, and leave enough overhang to keep summer sun out all the better. If not you can use a solar pergola, (it has slats at the mid winter sun angle) ours lets in almost 90% mid winter sun and 0 mid summer sun.

Well I guess we have really good ventilation, right on the beach, southerly windows open right into the "Dr", security flyscreen on the back door (south facing). Highest point of the house has hoppers opening to the north, if there's not enough wind we get a convection effect as well. House usually cools down to within a few degrees of outside minimum temperature.

So are you saying, there's enough insulation in the ceiling and whirly birds to cope with the heat from the black roof?
And your curtains control the big eastern glass???
Cause once the heat's inside the windows, it's very hard to stop it getting into the rest of the house.
where as once the heat's in, it's not so hard stopping it from getting out. (it radiates and conducts in, but it only conducts out, that's how a glass house works)

And only 50% of the North wall needs to be glass, unless you're in Tassy, or up a mountain.

OK so you may be able to go against the "old school" and get a building that works, but it's going to have to be more complicated and more expensive to do so.
Seems to me old school is simple and easy, fair enough there is more to getting the best results than just orientation, and correct eaves and insulation. the building, it's location, occupants lifestyle, and a whole host of factors need to be taken into account.
But giving the general public, the idea that you can have a black roof and no overhangs with lots of eastern and/or western glass, is highly irresponsible.
Maybe you can do it somehow, but without giving all the does and don'ts that make it possible, people are going to end up with an extremely uncomfortable house, with huge electricity bills.

I have noticed that the local birds (pigeons) favour the dark roofs during the cooler months. Unfortunately they show their appreciation by crapping!

hi decrepit, the upstairs is lightweight so the heat can be rapidly removed with cross ventilation.

the roof is sarked, no whirly birds. topped things up with the rud free insulation 3 weeks ago and put R3.5 in the ceiling.

the glass faces east becasue that has a view. i checked this morning and by about 9am you can just start to feel the heat building. by 9.30 the sun is high enough that we open the curtains and windows on the eastern side and the heat is removed in a couple of minutes.

in winter we close the curtains on dusk and open again when going to bed and things are toasty all morning.

my house looks like your typical unattractive project home. difference is i designed it. the builder didn't have a 2 storey house in my very small budget so i designed one for them. once they had removed any detail and told me that they wouldn't build skillions we built what looked like all of the other houses only a more brutal version and of course to my floor plans, actually it's very brutal . they also told me i needed 200sqm total build, so i stuck a neo classic portico on the front as a bit of a piss take plus to shade the west. even put a round window in as it's near the water. (always the smart arse)

in short,

almost no west facing glass. (the street)
no hallways
complete cross flow
high mass ground floor low mass first floor
living upstairs
4 bed 2 car
polished particle board etc etc.

even when there is no breeze the smaller windows on the west side suck the air through from the big windows on the east/north

cost $130k

one regret is not having more southern windows. i reduced the amount of southern windows as the house is hard up on the southern setback and i didn't want to hear or see the neighbours. also when i say no overhangs, it has overhangs, some are 150mm and others 400mm

also in response to the comment about irresponsible to suggest black roofs are ok and overhangs are over rated. i understand your point,

but,

it's not hard to design something that works even with black roofs and no overhangs if that's what you are into. the fact that someone might take those 2 ideas and design a bad outcome is not my fault. reality is anyways, most people are going to end up with a bad outcome regardles of what i say here because they will buy a poorly designed project homes. even with overhangs and a light roof it still won't work. if they were to go to a quality architect or building designer they wouldn't get a much better outcome and it would cost more.

hey decrepit,

i thought of a better way of putting it. i should have just said this in the first place.

most house designs have more issues to worry about than whether the roof is black. just getting the basic planning right would be a start.

Gestalt said...

hey decrepit,

i thought of a better way of putting it. i should have just said this in the first place.

most house designs have more issues to worry about than whether the roof is black. just getting the basic planning right would be a start.

OK. can't ague with that!!!!!