Carbon Negative, Cost Positive: Why Sustainable Materials Are Becoming the Smart Choice

Low‑carbon building materials like hempcrete, superwood, and seawater‑derived concrete are quickly moving into the mainstream in both the UK and the US. This shift is driven by procurement policies such as Buy Clean and green certifications like BREEAM and LEED. In this post, Jamie Trevett explains which sustainable materials are deployable today, why early adopters are winning contracts, and how trades need to adapt to stay competitive.

Net‑zero isn’t just a slogan; it’s a requirements checklist for new build contracts.

In the US, the Buy Clean initiative is actively shaping procurement. Federal and state agencies are prioritising low‑embodied carbon materials like steel, concrete and glass and now many major states have formal policies in place. That move is pushing public and infrastructure contracts to score bids on environmental performance. (BlueGreen Alliance overview, Climate Policy Dashboard state data).



In the UK, frameworks like BREEAM, Pas 2080, and LEED are rewriting how spec and contractor evaluation works, even for schools, social housing or commercial envelopes. The takeaway? If you quote high-carbon wall systems without a low-carbon alternative, you're likely already off the list.

These materials aren’t experimental, they’re already being used

Low-carbon technologies are shifting fast. Consider these:

• Hempcrete, made from hemp fibres and lime, is now used in retrofit and commercial modular builds in the UK. It regulates moisture and stores CO₂ over its lifespan, offering insulation plus carbon credentials.
• Superwood from InventWood in the US is engineered from densified wood and claims eight times the strength of natural timber with significantly lower embodied carbon. Developers in green-rated campuses are piloting it now.
• Seawater-derived carbon-negative building material, developed by Northwestern University researchers, uses electricity and CO₂ to create sand-like minerals suitable for concrete, plaster and paint. The process permanently captures CO₂ during material creation.



These technologies are not theoretical. They’re priced into new builds, especially where environmental scoring is in play.

Contractors using carbon-smart materials are winning bids

We’ve seen modular-build companies in Oxford, housing associations in Boston, and schools in Seattle land contracts over competitors, not because they were cheaper, but because they offered low-carbon solutions installed by trained teams.

Owning the supply chain from materials to installation gives them performance-based advantages in tenders tied to net-zero or sustainability metrics.

This requires new trades and training

Traditional materials paths are still important. But without adaptation, your workforce will fall behind quickly.

Today’s demand includes:

• Dryliners and plasterers trained in low-carbon systems like hemp-lime or superwood.
• Fit-out teams versed in bio-composite panel sequencing.
• Project managers who understand embodied carbon data and EPD reporting.
• QS professionals who cost low-carbon alternatives accurately.



This is not minor upskilling, it’s a paradigm shift in how teams prepare to deliver modern specs.

It’s not just green, it’s pragmatic

Contractors using these materials report:

• Faster prefab installs with hemp-based panel systems.
• Thermal envelope performance that removes the need for additional HVAC.
• Lower weight loads resulting in reduced foundation work and transport.
• Positive environmental scoring that supports margins and sustainability KPIs.



Working with the right materials not only wins bids, but it also cuts rework and life-cycle cost too.

Final Take

Carbon-negative materials are no longer optional; they are becoming table stakes. If your team hasn’t adapted to thinking about carbon and climate impact during tender prep, you may already be priced out of many public and sustainable projects.

Train your crews. Understand what’s being specified. Adapt or risk being left behind.