[Bootwizard]

What about recycled plastic? I've seen parks use it well for durable bridges, benches, gazebos, etc. For some reason I haven't seen it used for homes and that confuses me. It seems like a generally durable and even weatherproof material.

[dirtyid]

Not for structural use, which engineered wood is good replacement for concrete. Mybe some exterior cladding applications where there's already a lot of plastic products, I know some exist with recycled plastic but they seem pretty niche. Performance requirements for habitable environments (insulation, moisture control, outgassing/toxcity in fires etc) is different from outdoor use. It's probably down to process cost and scale, and the regulation around construction is generally pretty conservative.