We have a ritek Roof here in our holiday house. We have also lined the Ritek roof inside with a plaster ceiling which helps (we didn't like the look of corrugated tin for inside). It is not that different from noise on our conventional tin roof in Brisbane. Any tin roof is noisy. We had really heavy rain last night, had to turn up the TV but overall very happy with its other qualities and would use it again.

Judging by the plan, the photos and your comments it appears that too much heat is coming in from high light glazing (clerestory windows) into the lounge and dining areas. Both rooms will be cold in winter because the direct heat from these windows is not enough and not absorbed in an thermal mass and they do not have ground level windows or glazed doors facing north. The elevated floor means that it is cold under the house so heating in winter goes down as well as up. The roof would lack adequate insulation due to the period in which the house was built. The roof tiles probably have another 15 years maybe a bit more so it is costly to insulate from the top (i.e. taking roof tiles off adding insulation then putting roof tiles back in again. The colour of them is contributing a lot to the heat. So what to do. - add external shading device to the highlight glazing, maybe timber battens 40 x 40 at 20mm spacings. This will block direct sunlight within the shading season. That helps to reduce heat intact and see how you go. If that does not work then - add a rigid foam core board to the underside of the timber ceiling, e.g. Foilboard which is 20mm thick r 2, then install a 12mm plywood ceiling lining under this. That way you retain the timber rafter ceilings but also one that has a light coloured (hoop pine ply) timber in between. (Note this is costly) - big gains in heat loss is achieved with underfloor insulation. Try r3 bulk squeezed tightly between the floor joists. Then you can plan for the future with the following - change glass in windows and glazed doors to a low e glass - install insulation into the cavity of the external walls using a company called envirowall. - replace roof tiles with a light coloured metal roof, replace the existing roof battens with a 100 x 40 batten so that you can install a 100mm thick anticon insulation. All of the above costs money and if you don't do it then it costs money to burn energy to keep the living rooms between 21 to 27 degrees year round (what we consider comfortable) so if it tough to decide what to do or not. As an alternative For about 40k you could spend 30 of it on solar cells, and an awesome battery (Tesla powerwall 2) and buy some wall mounted ac units. But that would be kicking the can down the road. But sometimes you have no choice. Good luck

Sandwich panel should be cheaper as you potentially won't require any rafters only a beam at either end for support. You can use quite thin panels as well. Some companies do a 50mm panel that will span 7.00 metres+ depending on wind class. Get the whole job priced before deciding. I've done quite a few and the sandwich panels are usually cheaper as well as providing insulation, less maintenance, etc.

Thank you. The level of insulation provided by ICF construction depends on the type of ICF system is used and the thickness of insulation, but it is often greater than R3. In Australia the insulation levels achieved in ICF construction is in the range of R3 to R6 . We used the 203mm foam blocks that gives an overall width of around 225mm.