The Breathable Building Revolution: Why Steico, Diathonite, and Hemp are Winning
If you’re insulating a home today, the old way—using plastic foams and fibreglass—is quickly being replaced. The future is biophilic insulation: using natural materials that breathe, regulate moisture, and keep your home at a perfect temperature year-round.
The “Big Three” of this movement are Steico, Diathonite, and Hemp. Here is why they are the dream team of sustainable construction.
Steico: The “Tree Hugger” for Your Walls
Steico is made from compressed wood fibres. Think of it as wrapping your house in a thick, protective wooden blanket.
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Summer Cool, Winter Warm: It has “thermal mass,” meaning it keeps your rooms cool in summer while trapping heat in winter.
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Eco-Warrior Status: It stores more carbon than it takes to produce. By using it, you’re literally locking carbon dioxide into your walls.
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The “Gore-Tex” Effect: It’s vapour-open. It lets moisture escape, keeping your home dry and rot-free.
Diathonite: The “Magic” Cork Plaster
Diathonite is a spray-on thermal plaster made of cork, lime, and clay. It’s the ultimate solution for tricky, old, or uneven walls.
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No More Gaps: Because it’s a liquid plaster, it fills every nook and cranny. No gaps means no drafts.
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The Damp Fighter: It’s a natural dehumidifier. It sucks moisture out of damp masonry and releases it safely into the air.
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Fireproof & Tough: It’s highly fire-resistant and won’t be damaged by salts often found in old brickwork.
Hemp: The Super-Plant Performance
Hemp insulation (usually found in flexible batts or “Hempcrete”) is the rising star of the eco-world. It’s incredibly hardy and versatile.
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Naturally Pest-Repellent: Hemp contains compounds that naturally deter insects and rodents without the need for toxic chemicals.
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Structural Health: Like its cousins above, hemp is “hygroscopic.” It manages humidity beautifully, serving as a natural air conditioner for your indoor climate.
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Rapidly Renewable: While trees take decades to grow, hemp can be harvested in just 100 days.
The Price: An Investment vs. A Short-Term Fix
Let’s be honest: these products are not cheap. You will pay more upfront for Steico, Diathonite, or Hemp than you would for standard synthetic foam or mineral wool. However, looking at the price tag in isolation is a mistake.
To find the actual cost, you must look at the life of the building:
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Avoiding the “Synthetic Trap”: Cheap synthetic insulations often trap moisture against the structure. Over 10–20 years, this frequently leads to interstitial condensation, mould growth, and timber rot. The cost to strip a wall and repair structural damage can be ten times the original “savings” on the insulation.
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Durability: Natural materials like cork and wood fibre don’t sag, settle, or degrade over time. They remain effective for the lifetime of the building, whereas synthetics often lose their R-value as they age or encounter moisture.
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Energy Efficiency: Because these materials offer better “thermal mass” (keeping heat out in summer and in during winter), your monthly utility savings are consistently higher than with lightweight synthetics.
In short, Natural insulation is an investment in the building’s health. Synthetics are a budget choice that often results in substantial repair costs down the line.
The Ultimate Power Move: The Triple-Threat System
Why choose one when they work even better as a team? In high-end renovations, builders use a “Sandwich Technique”:
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The Base (Diathonite): Applied to wonky, old stone or brick walls to level them out and stop dampness.
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The Core (Steico or Hemp): Rigid Steico boards or flexible Hemp batts are installed to provide the bulk of the heat-trapping power.
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The Result: A perfectly airtight, ultra-insulated wall that is virtually immune to mould and cold spots.
The Bottom Line
If you want a home that feels fresh, stays quiet, and slashes energy bills without trapping moisture, these materials are the gold standard. Steico provides the muscle, Diathonite delivers the precision, and Hemp provides the ultimate sustainable edge.