Phil_C
Member
Hello All
I am building a house in a Zone 2 area. I am putting 50mm EPS insulation under the slab and either 30mm or 50mm around the perimeter. The slab is a stiffened raft slab that does not use waffle pods. Do I need to insulate around the edge and internal beams which are 450mm deep? The slab itself is 125mm thick. I will have hydronic heating in the slab.
House will be on level ground in Class M soil.
Thanks in advance
Phil
arttt
Member
Zone 2 is described as
"Warm humid summer, mild winter"
http://www.yourhome.gov.au/introduction/australian-climate-zones
You dont want to insulate the slab as the mass of the ground should help with those warm summers. Im not sure on perimeter insulation i suspect not worth it.
Hydronic heating in slab is a bad idea in a mild winter climate. It works best where you need consistent heating for weeks on end. Really it shouldn't be hard to need no heating with a small amount of good thermal design.
If you are having a reverse cycle air conditioner then it can provide heat as well with zero additional upfront cost and its probably the cheapest heating to run.
planeguy
Member
Can I hijack for a very similar question. We are building in Zone 7 (ACT) and are planning 100mm EPS under slab. The engineer has not shown insulation under the beams, and the architect is showing 25mm XPS for the beam edge insulation.
Is it possible /worthwhile to insulate under the beans? Should we also try for more than 25mm on the slab edge (it seems low to me)
