I'm not convinced. Only systems that require rigid piping are sewers, air conditioning and sprinklers. (But does air conditioning really require rigid piping?)

I'm not convinced. Only systems that require rigid piping are sewers, air conditioning and sprinklers. (But does air conditioning really require rigid piping?) Sprinkler system is usually quite rigid, but is there any reason why you could not use flexible parts every now and then? Hydraulic machinery routinely has 60MPa in flexible hose. Laminated wood should have smaller heat expansion coefficient than steel or concrete. Obviously this can turn into problems if you hot air conditioning steel pipe gets longer than the surrounding building. PVC has significantly higher thermal expansion coefficient than any of these. So the collars have to have some give anyhow. If you get moisture swelling, you are fucked anyhow. Wooden building has to be designed so that you stay between 17% - 20% moisture content at all times. Currently wooden small houses have their lateral support done by steel. I'm really skeptical how much this really matters.