At the end of the day, when you’re standing on your own plot of land, hammer in hand, ready to build or renovate your dream home, the buzzwords start swirling around you. “Hempcrete,” “clay bricks,” “embodied energy,” “U-value,” and a whole lot of marketing fluff that makes your head spin. You want something green, affordable, and durable — not just what sounds trendy or what the sales rep pushes. So, let’s cut through the jargon and look at the real deal: are hempcrete bricks better than clay bricks for your project?
Setting the Scene: Why Not Just Use Concrete?
First off, you’ve probably heard concrete is bad news for the planet — and you’re right. The production of Portland cement, the main ingredient in concrete, is responsible for about 8% of global CO₂ emissions. For environmentally conscious builders, that’s a big red flag. Plus, concrete can be heavy, energy-intensive to produce, and doesn’t always offer great insulation without extra layers.
Enter clay bricks and hempcrete bricks — two alternatives with their own sets of advantages and challenges. I’ve worked on projects using both, and I carry a little piece of history (and a worn-out brick sample) in my bag to remind me that sometimes old materials still have a lot to teach us.
What Are Clay Bricks and Hempcrete Bricks?
Clay Bricks
Clay bricks have been the backbone of construction for thousands of years. Fired at high temperatures, they’re incredibly durable, weather-resistant, and provide good thermal mass — which means they can store and slowly release heat, helping to regulate indoor temperatures.
Companies like Glen-Gery and Belden Brick Company produce a wide variety of clay bricks, with prices generally ranging from $0.50 to $2.50 per brick depending on quality, finish, and size.
Hempcrete Bricks
Hempcrete is a relatively newer material made by mixing the shiv (woody core) of the hemp plant with a lime-based binder. It’s lightweight, breathable, and has gained attention for its eco credentials. Hempcrete bricks are generally not load-bearing, meaning they often need a timber or steel frame for structural support.
Hempcrete is praised for its insulation qualities and carbon-negative potential, as hemp plants absorb CO₂ while growing.
Hempcrete Pros and Cons: What You Need to Know
Let’s break down the main pros and cons of hempcrete bricks based on my experience and research. Here’s what I’ve seen firsthand and what the literature confirms:
Pros
- Low Embodied Carbon: Hempcrete has a significantly lower embodied carbon footprint than fired clay bricks or concrete. The hemp plant absorbs CO₂ as it grows, and the lime binder requires less energy to produce than cement. Some studies even claim hempcrete can be carbon-negative over its lifecycle. Excellent Insulation Value: Hempcrete’s insulation value is around R-1 to R-2 per inch, which is much better than traditional clay bricks (which have an R-value close to 0.2). This means hempcrete walls can help reduce heating and cooling demands. Breathability and Moisture Regulation: Hempcrete walls regulate humidity well, reducing risks of mold and improving indoor air quality. Lightweight: Easier to handle on site and reduces foundation loads, potentially lowering foundation costs. Fire and Pest Resistant: The lime binder makes hempcrete naturally fire-resistant and pest-resistant without chemicals.
Cons
- Structural Limitations: Hempcrete is not load-bearing, so you still need a structural frame (usually timber or steel), which adds complexity and cost. Higher Upfront Costs: While the hemp itself is renewable, lime binders and specialized labor can push costs higher than traditional clay bricks. Hempcrete bricks aren’t widely available everywhere yet, which can increase shipping or custom manufacturing expenses. Drying Time: Hempcrete takes longer to cure and dry fully (up to several weeks), which can slow construction schedules compared to fired bricks. Lower Durability: Hempcrete is softer and more prone to mechanical damage than clay bricks, requiring careful handling and sometimes additional protection on exterior walls. Availability and Expertise: Hempcrete is still a niche material, so finding skilled builders and suppliers can be a challenge.
Clay Bricks: The Tried-and-True Classic
Clay bricks have a long track record of durability and performance. Here are some key points to consider:
Pros
- Durability: Fired clay bricks last for centuries if maintained properly. They resist weather, pests, and fire. Thermal Mass: Clay bricks absorb heat during the day and release it at night, smoothing indoor temperature swings — especially valuable in climates with a big day-night temperature difference. Wide Availability and Familiarity: Clay bricks are widely available and well understood by builders, making sourcing and construction straightforward. Cost-Effective at Scale: At $0.50 to $2.50 per brick, clay can be affordable, especially for larger projects with easy access to local brickworks.
Cons
- High Embodied Energy: Firing clay bricks requires significant energy, usually from fossil fuels, leading to a higher carbon footprint than hempcrete. Poor Insulation Value: Clay bricks have low R-values (around 0.2 per inch), meaning they need additional insulation layers to meet modern energy codes. Heavy: The weight of clay bricks adds to foundation requirements and transport energy. Environmental Impact of Clay Extraction: Mining clay can cause landscape disruption and habitat damage if not managed responsibly.
The Numbers: Embodied Energy and Insulation Values
Material Embodied Carbon (kg CO₂e per m² wall) Insulation Value (R-value per inch) Cost (approx. per brick) Clay Brick 150 - 200 ~0.2 $0.50 - $2.50 Hempcrete Brick 10 - 30 1.0 - 2.0 $1.50 - $4.00 (less common)Note: Embodied carbon values can vary depending on production methods and transport distances. Insulation values depend on density and mix ratios.
Practical Considerations for DIY Builders and Renovators
So, what does this mean for you—the budget-conscious, eco-aware DIYer?
Assess your climate and goals. If you live in a climate with large temperature swings, clay bricks’ thermal mass can be a big plus. But if you want superior insulation built into your walls to reduce heating and cooling costs, hempcrete shines. Consider structure and timeline. Hempcrete requires a frame and longer curing time, which might complicate a DIY build unless you have experience or help. Clay bricks, on the other hand, can be laid by skilled DIYers with standard tools and techniques. Calculate lifecycle costs. Hempcrete may cost more upfront but can save money on insulation and energy bills over time. Clay bricks might be cheaper initially but often require additional insulation and maintenance. Source locally. Clay bricks from Glen-Gery or Belden Brick Company can be found in many regions, reducing transport emissions and cost. Hempcrete bricks are less common but check nearby natural building suppliers or hemp farms. Beware of greenwashing. Some products marketed as “hemp” or “eco-friendly” are actually mixes with synthetic binders or plastic additives. Look for 100% natural lime binders and hemp shiv without fillers.Final Thoughts: What’s Better — Hempcrete or Clay Bricks?
In my 15 years of sustainable building projects, I’ve learned that no single material is a magic bullet. Hempcrete bricks offer excellent insulation and re-thinkingthefuture a much lower carbon footprint, making them ideal for those prioritizing energy efficiency and environmental impact—and willing to manage structural framing and curing time.
Clay bricks remain a solid, durable choice with unmatched thermal mass and ease of use, especially where budgets are tight and local supply is strong. They can be combined with modern insulation strategies to make a comfortable, efficient home.
For DIY builders and renovators, the best approach might be a hybrid: use clay bricks where strength and durability are paramount, and hempcrete for insulation or non-structural infill. Or, explore hempcrete for interior walls or renovation projects where weight and breathability matter.
Remember, the worn brick I carry in my bag is a reminder that sometimes the oldest materials teach us the best lessons—but new ones like hempcrete might just help us build a greener future.
Resources and Where to Learn More
- Glen-Gery Brick Company Belden Brick Company TreeHugger - For practical green building tips Apartment Therapy - For DIY and home inspiration Hempcrete Insulation Value Explained