Does anyone know how much heat transfer gets thru a concrete slab roof direct sun all day Assume 4 inch thick slab? or would it be better to use some q con aerated concrete panels and then pour a slab on top of them?

I cant decide when I build whether to have a slab roof or a normal tiled, steel truss roof, the steel truss rather limits the design although I see in Madeira they build a slab roof and then just bolt onto that a pitched roof tiles and all just for physical appearance.

Or how about a slab roof similar to above with a stee framed and tilel roof just raised a few inches off the slab allowing air under to remove excess heat keeping the slab cooler.

Or am I nuts? hahaah

A concrete flat slab roof is expensive and difficult to keep water tight. It is used mainly for architectural reason, like on top of a high-rise, or for some, as an extended floor space.

Heat insulation is not a problem. Most simple method is to use solar slab panels, which is 30x30cm pre-cast concrete panels with 5cm legs on each corner. The air pocket under the panel provides the insulation. A second layer of insulation will be the space above false ceiling below the roof slab.

Using Q-block is inferior due to heat retention of the block mass.

But in either cases, make sure you first get the roof slab water tight, and properly drained.

Thanks tRogers I do have concerns over water penetration ie cracking and membranes etc long term durability.

Here is a pic of the solar slab.

Thanks tRogers I do have concerns over water penetration ie cracking and membranes etc long term durability.

I do not like membranes. If it fails, the whole thing has to be removed. I prefer direct treatment of surface. Where it leaks is where it fails and we can repair it directly from the underside of the roof slab. I use Radcon for my condo projects:

http://www.radcrete.com.au/productDetail.a...=1&c=133826

You can contact K. Sutisa 081-268-5044

Thanks tRogers I do have concerns over water penetration ie cracking and membranes etc long term durability.

I do not like membranes. If it fails, the whole thing has to be removed. I prefer direct treatment of surface. Where it leaks is where it fails and we can repair it directly from the underside of the roof slab. I use Radcon for my condo projects:

http://www.radcrete.com.au/productDetail.a...=1&c=133826

You can contact K. Sutisa 081-268-5044

Thanking you.