Earthen renders are one of the oldest building finishes on Earth — and also one of the most relevant for our future.

Long before cement, polymers, and synthetic additives entered the construction world, people finished their homes with what was available underfoot: clay, sand, fibres… and yes, animal manure.

If you’re interested in natural building, you don’t need to look much further than your local paddock. Horse poo, cow poo, and other herbivore manures have been used for thousands of years to strengthen earthen and lime renders, improve durability, and create breathable, repairable finishes that work with buildings rather than against them.

A Long History — Including in Australia

Across the world, dung has played a quiet but vital role in construction. In Africa, the Middle East, India, Europe, and Central Asia, manure has been mixed into plasters and floors for centuries. It was common knowledge: fibrous dung reduced cracking, increased cohesion, and improved longevity.

In Australia, First Nations peoples used clay-rich earths, plant fibres, and animal binders for shelter, hearths, and surface finishes long before colonisation. Later, early settlers adapted European earthen building techniques to Australian conditions, often using cow and horse manure on farms and rural homesteads where materials were scarce but animals were plentiful. In many cases, these finishes are still performing over a century later.

Why Manure Works

It might sound unconventional, but there’s solid material science behind it.

Herbivore manure contains:

• Undigested plant fibres (especially cellulose)

• Natural enzymes and binders

• Fine particulate matter

These fibres act much like straw or hair, adding tensile strength to renders. This helps control shrinkage during drying, reduces cracking, and improves impact resistance.

Horse manure is particularly useful because horses digest inefficiently. Their manure contains long, intact grass fibres that disperse beautifully through a mix. Cow manure, while more digested, contains finer fibres and sticky binders that enhance cohesion and smoothness.

Horse Poo in Lime Renders

Natural building? Look no further than your local equine.

Horse poo is an excellent fibre source for lime renders, especially base coats. I use it in nearly all my base coats because it:

• Adds tensile strength

• Helps control cracking

• Improves workability

• Bonds well with lime and sand

• Is cheap (often free)

• Is widely accessible

Most importantly, it maintains a genuine connection to the organic nature of natural building, rather than introducing plastic fibres or synthetic additives that eventually return to the earth as microplastic pollution.

When mixed properly and allowed to pre-soak, horse manure integrates seamlessly into lime or earth plasters. Once cured, there is no smell — just a strong, breathable, resilient render.

Strength, Breathability, and Performance

Earthen and lime renders with manure fibres don’t aim to be “hard” in the cement sense. Their strength lies in flexibility, breathability, and repairability.

These renders:

• Move with buildings rather than cracking catastrophically

• Allow moisture to pass through safely

• Reduce condensation and mould

• Are easily repaired without demolition

• Improve indoor comfort and air quality

In bushfire-prone and extreme-climate regions, breathable renders help walls dry faster after rain or firefighting, reducing long-term damage and mould risk.

A Cultural Shift Back to Common Sense

Modern building has trained us to distrust materials that don’t come in bags with barcodes. But earthen renders remind us that intelligence doesn’t always look industrial.

Using horse or cow manure isn’t about nostalgia or novelty — it’s about material honesty. It’s about choosing low-energy, non-toxic, locally sourced ingredients that perform beautifully and return safely to the soil at the end of their life.

Every bucket of manure-based render replaces plastic fibres, acrylic binders, and carbon-heavy products. It also reconnects builders to place, process, and tradition — something sorely missing in modern construction.

From Paddock to Wall

Earthen renders are tactile, grounded, and deeply human. They invite hands-on learning, experimentation, and care. They remind us that buildings don’t have to be manufactured — they can be grown, mixed, and maintained.

So yes, we’re talking about poo. But we’re also talking about resilience, sustainability, and building in ways that make sense for our climate, our communities, and our future.

Sometimes the best materials really are right under our feet.