If the shed has not yet been built you might consider a lesser pitch with a view, ultimately, to a green roof.
There are numerous methods for doing this, but all agree that insulation from a turf/green roof is outstanding. Would be worth speccing up the frame to be sure you could do this.
Otherwise I disagree with your notion of minimal insulation. According to this website http://www.energyrating.gov.au/acl.html your 14 x 6m shed would need a 10kW air-con unit to keep it cool. Another one I looked at suggested 12kW!!
Such a unit would cost $2/hr to run (while the motor runs, not the whole time it's on, obviously) which will add hundreds to the electricity bill each quarter.
My advice would be to use a large industrial-size oscillating fan (about 800mm diameter) and save your shekels to eventually line the ceiling and insert R3.5 batts.
It's easier to do this before the roof goes on, but if cost is an issue right now, you don't have a choice. Use a foilboard product under the sheeting and plan for batts down the track.
Add more windows and/or doors to the shed/studio prior to construction, especially on the side the prevailing winds arrive. If the orientation due to site conditions doesn't allow for this, then post-construction build breeze dams at 90 deg from the walls downwind of the door or window that will best capture the breeze.
This needs to be solid, as it effectively forms a funnel-like effect, trapping whatever breeze there is. This in turn creates a high-pressure zone just outside the door or window, which automatically forces the air at a higher rate into the building through the door/window.
It also helps if the exit door/window on the far side of the building is larger, as this helps increase the flow rate of the breeze thru the building.
Of course, if there is no natural breeze, use the big oscillating fan. They cost only about 1.5c/hour to run, rather than the approx $2/hr a 10kW A/C unit would cost.
Another good tip for passive cooling is shade.
The quickest, cheapest way to create shade is clumping bamboo. Not the runner type! Bamboo can grow to a height of 5m inside a year if watered and fertilised well.
Plant this approx 2.5m from the walls. Plant deciduous shade trees 5m from the walls and wait for the trees to grow. Once grown enough to shade the building, remove the bamboo.
The downside of bamboo is that it is an evergreen, and therefore will shade the studio during winter as well as summer, but it's usually easier to heat a shed than cool one!
Hope that helps!
Cheers
Mark
Posted Friday 9 Apr 2010 @ 8:38:59 am from IP
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