[SECProto]

> How many houses, without preservatives in the wood, would rot and be rebuilt, compared to 100% concrete/rock housing?

This isn't a great comparison, as unreinforced concrete is not used for structures. If you're speaking about steel reinforced concrete, they usually have a lifespan in the 100 year range for something protected from the elements like structural walls (assuming the aggregate is well chosen to avoid sulphate attack). For comparison, much of the housing stock in my area is stick framed and is of a similar age - ~70 years.