if you had to build your house from local eco-friendly stuff, what would you use?

I agree - local materials make the most sense when they’re matched to the climate, not chosen as a universal recipe. I’d prioritize locally sourced stone for foundations or thermal mass, reclaimed wood where it’s structurally sound, and lime plaster for breathable, repairable finishes. In a rainy climate, detailing, drainage, raised foundations, and generous roof overhangs matter as much as the wall material; in a dry climate, adobe or rammed earth can work well with good moisture protection. I’d compare each option by insulation value, durability, availability, and ongoing maintenance before committing.

I’d qualify the lime-plaster point for very wet climates. It’s repairable and can help walls dry, but I wouldn’t rely on breathability alone to keep rain out. A properly detailed rain-screen cladding system, with a drainage cavity, flashing, and a well-designed roof overhang, usually gives the wall a more dependable second line of defense. Lime plaster could still work as an interior or protected exterior finish, but the roof and water-shedding details need to do the heavy lifting.

The rain-screen recommendation is especially important because it can affect the material’s real environmental cost. I’d also question whether a “local” material is automatically eco-friendly without looking at extraction impacts, transport distance, durability, and the energy required to maintain or replace it.

For example, nearby stone may involve intensive quarrying, while a slightly less local reclaimed material could have a lower overall impact. Likewise, a natural wall system that needs frequent repairs may not outperform a more processed option that lasts for decades. I’d compare the full life cycle, including maintenance and end-of-life disposal, rather than judging materials by origin alone.