Like most concrete slabs, reinforcing bar is required to help give the slab it's strength. And like all material choices that can be made during the course of construction, one can choose to make a sustainable choice or not. In the case of the reinforcing bar we have chosen to use reinforcing bar from a supplier who uses 100% recycled steel. By using recycled steel, the environmental impact of the steel has been reduced. Recycling steel uses a lot less overall energy than mining ore, and precessing it in order to make new steel.
What is more, the strength and quality of the recycled material is the same as the new material.
The photo above shows the steel reinforcing being placed inside the form work for the concrete slab.
Timber wall and roof framing is still the dominant material for house construction in Sydney. Unfortunately this is the favorite food of one of our native creatures, termites. So it is necessary to have some form of termite protection when you build in timber in order to prevent your house being eaten out around you!
Termite protection can take many forms and more often than not involves some from of pesticide. The key is, to avoid spraying termite barriers on the soil and ground around your house. Not only are they toxic for termites, but they aren't particularly good for humans and the ground ecology.
Several new products on the market seek to address this issue by safely encapsulating a termiticide within a 'blanket' a bit like thick plastic, which can not leach the termiticide. These blankets are used to protect around pipes such as the one above, which prevent termites from entering your house by forming a physical barrier that the termites can not penetrate.
To heat the house in winter we have installed a 5 star gas in slab hydronic heating system. For those who don't know what I am talking about, a hydronic heating system is essentially heated water running through pipes, the pink ones in the photo above, which delivers heat to a location, in our case, the concrete slab.
Hydronic heating is very efficient because is works on the principle of radiant heat, which warms objects rather than convective heat which just warms the air. What is more, in slab hydronic heating is doubly efficient because the heat starts at the bottom most point in a room and rises to the top, heating everything along the way. Rather than air conditioning which generally tries to heat the air in a room from the grilles in the ceiling, down. One way is working with nature, heat rises, and the other is trying to fight it.
For in slab hydronic heating to work at its best, the floor should not have an insulating covering such as carpet or timber. So tiles or exposed concrete in our case, tend to be the best.
Above is the manifold which looks after the balancing of the hydronic heating pipework. Put simply, the two white pipes on the left are the flow and return from the gas boiler and the red is the heated water going out to the slab and the blue is the heated water returning back.
The heating system is designed as a closed loop, so the same water stays in the pipework getting heated at the boiler, then going through the red manifold and out to the slab, then back to the blue manifold and then on to the boiler to get heated and start again. Pretty simple really.