Sustainable Lumber: FSC Certified and Alternatives Quantify the upfront carbon impact of your assembly choices with the Embodied Carbon Calculator(/tools/embodied-carbon-calculator) — wood-framed walls and biogenic insulation can drop a typical 2,000 sq ft build by 10+ tonnes CO2e. Choosing sustainable lumber is one of the quickest ways a DIY eco builder can lower a project's carbon footprint while keeping costs under control. This guide explains what sustainable lumber means, how FSC certification works, and practical alternatives—reclaimed wood, PEFC-certified supplies, and engineered timber—so builders can match material performance, carbon, and budget for small homes, tiny houses, and retrofits. TL;DR: - Reclaimed or local timber can cut embodied carbon(/glossary/embodied-carbon) by roughly 50–80% versus new imported engineered products; expect variability by source and transport. - If buying new material, prefer FSC or PEFC certified framing; certified stock often carries a 5–30% ...