kate
there's a lot of issues you've raised there and it would be helpful to see some photos of the house, especially the problem areas.
Can you take photos with digital camera and upload to photobucket or similar site and post url here to view pics?
Even without them, I'd say you're suffering from the pre-compulsory-insulation period of piss-poor brick-veneer construction - although I'm curious about that as you sauy the builder is coming to put gyprock over the bricks??? Does this mean you have double brick walls and are contemplating gyprocking over them or what???
Ritek is not cheap, and based on their published R-values, you'd need a celiling/roof panel of 140mm thick to get a decent R-value for the upstairs enclosed patio. This gives apparent R-value of R3.4.
I would not put a ventilator through it as it will weaken the panel and create a brak in the insulation.
As you say it's a villa, and you mentioned body corporate, I presume this preculdes any modifications to the outside walls?
Generally with brick veneer wals exposed to the sun, especially west-facing walls, it is better to put an insulated false wall on the OUTside, rather than a false wall of gyprock on the inside. And Ritek panels might be good for this, as you would only need to batten the wall with treated pine 75X50 battens and fix the Ritek panels directly to the battens. 100mm Ritek is about R2.5.
This creates both reflective barrier, insulation and an air gap, so would be a good solution, and being "architectural" panels, might fly past the body corporate, but the BC would 'own' them once installed, so they would want to be sure of some objective life span for the false wall structure.
You would use Colorbond steel angle flashings to existing window reveals, so you would effectively have an additional 150mm deep reveal on the outside, thus making some eave shade at windows as well.
Weatherproofing the top of the panels is similar, just with wider angle or barge flashings. Quite simple really.
Powered roof vents are the only real solution, as the non-powered ones are relatively ineffective. People on other threads have discussed this and the consensus seems to be the fans need to be able to replace the entire volume of air that has to be removed from the space, so may need more than one, and the cfm (flow rate) is the important value. There are solar-powered whirlybird type vents that might do the job there.
Openable skylights are also an option, and a couple of small opening skylights as close as possible to the ridgeline would be of great assistance in creating a purging airflow. Being unpowered they'd rely totally on convective flows, but this could be assisted with the aid of a large, powerful portable fan.
Posted Sunday 7 Nov 2010 @ 4:11:44 am from IP
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