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Peter Warne
07-11-2004, 03:32 PM
Hi all,

I don't know if anyone has any experience of this, but I have been looking into ways to cool our house, and come across a special insulating paint.

Our roof has a large surface facing west, and since we have cathedral ceilings, our bedroom is right under that west facing roof. Despite being insulated with pink or wool bats, our ceiling gets very hot and stays hot into the night in summer. Air conditioning goes against the grain because it's so energy greedy and expensive, so I've been considering putting an extra layer of insulation against the ceiling from the inside - a very fiddly job and esthetically risky.

Then I found a that several companies in Aust and elsewhere sell an insulating roof paint which has some sort of silica particles in an acrylic paint. It apparently blocks out 94% of the solar radiation, and produces a temperature reduction of up to 15 degrees when it's really hot. It sounds miraculous, and it has been used all sorts of industrial and domestic situations in Alice Springs.

It's not very expensive, the prices I've seen ranging between $3 and $10 per square metre of roof. That means I could paint our roof with it for about $450 - a modest price when you look at the options. The only question that nags at me is, with all the emphasis on passive energy management these days, how come this product isn't better known. It's been around for at least 10 years, so if this method performs as it is claimed to, how come everyone isn't using it?

So after that long story, the simple question is: has anyone used it or heard of it?

By the way, we've had heavy showers for the last two days here in Nimbin, the tanks are overflowing and every plant, tree and bit of grass, not to mention the weeds, is shooting lustily. More work to come.

Peter

gardenlen
07-11-2004, 04:37 PM
g'daypeter,

exactly mate 'how come everyone isn't using it?' i've heard of it never heard of anyone who used it though. in the end paint isn't permanent it all breaks down and wears out so to say. worst part most of it then needs some removal before recoating.

do you have spinners on the roof to draw out the heat trapped heigh in the ceiling?

do you have any roof cavity at all ie.,. space between ceiling and roof itself?

if so this may need ventilating as well.

we have pink batts and sizalation in our roof with spinners, but we have a scillion roof (3 meters high along the southern wall and 4 meters high along the north wall) with the high side facing north, those roof ventilators draw a lot of heat off, if you don't have them go for the good quality ones with bearings not bushes, a bit dearer but they are there for life.

you can get special ceiling vents that can be closed off for winter.

len 8)

Snake
08-11-2004, 05:00 PM
G'day Peter,

I have heard of solar reflective paint being used on the roof of a minibus that had been converted to a camper (although I didn't follow the logic of the owner applying 9 coats of said paint to the roof of the vehicle!). I thought it was fairly expensive however, but can't say I've ever investigated it.

ECOS Issue 119 (April-June 2004) contains an article about SkyCool, a newly developed paint that apparently performs remarkably well in the type of application you want:
"SkyCool - extraordinary paint on a hot tin roof p.12 [Open PDF file; 211KB]
SkyCool is a new roof coating that almost defies the conventional laws of physics. SkyCool provides a profound cooling effect that can halve the running costs of mechanical air-conditioning in buildings with metal roofs. "

[url]http://www.publish.csiro.au/ecos/index.cfm?sid=10&issue_id=3934#58827

Of course, this probably is not yet widely available, but it may be of interest - one issue may be that this is specifically developed for roofing applications so hopefully would weather appropriately?

Cheers,

Mark :D