Beyond Plastic: 5 Natural Insulation Materials That Fight Mold and Protect Your Health

Mold-resistant steam shower design by Et Sal Interiors in Westlake Village, CA, featuring elegant brass fixtures and a sleek, minimalist aesthetic.

In holistic construction, the pursuit of mold prevention, low VOC, and lead free often leads to the use of known toxic materials. I have a saying, "If its not found in nature is it truly necessary?" Lets face it, when building a holistic home we want the best of all worlds, non-toxic, sustainable, eco-friendly, and good for our bodies. Incorporating manufactured materials like plastic, which can cause health problems such as endocrine disruption, need to be kept to a minimum. So what are your options if you don't want to trade mold prevention for health problems. Enter natural non-toxic materials options. Yes, you read that right, they do exist. Here are five unique insulation materials that offer both non-toxicity and mold resistance:​

1. Shikkui Plaster: Originating from Japan, Shikkui is a lime-based plaster made from hydrated lime and calcium carbonate derived from reprocessed eggshells. It is highly porous, allowing walls to breathe, and possesses natural antifungal and mold-resistant properties. Additionally, Shikkui is fire-resistant and contributes to improved indoor air quality by absorbing VOCs and CO₂. For Los Angeles and So Cal residents like me the fire resistant properties comes as a needed extra benefit.

2. Seaweed Insulation: In Denmark, seaweed has been traditionally used as a building material due to its excellent insulation properties and resistance to moisture, pests, and mold. The Modern Seaweed House on the Danish island of Læsø showcases this application, where seaweed-stuffed "pillows" are used for façade insulation, providing a sustainable and mold-resistant alternative to conventional materials.

3. Mycelium-Based Materials: Mycelium, the root-like structure of fungi, can be cultivated into building materials that are lightweight, biodegradable, and naturally resistant to mold. Recent advancements have led to the development of mycelium-based materials capable of self-repairing over time, offering a sustainable and durable option for construction.

4. Oriented Structural Straw Board (OSSB)OSSB is an engineered board made by compressing layers of straw with a formaldehyde-free resin. When treated with borate compounds, OSSB becomes resistant to mold, fungi, and termites. It offers a sustainable alternative to traditional wood-based panels, with the added benefit of improved indoor air quality.

5. Hempcrete: Hempcrete is a bio-composite material made from the inner woody core of the hemp plant mixed with a lime-based binder. It is naturally mold-resistant, breathable, and provides excellent insulation. Hempcrete also has a negative carbon footprint, making it an environmentally friendly choice for construction.

Choices are always more easily made when we know our options. Natural insulation materials can be an option in your next home build or remodel project. While I am not an advocate for completely throwing the baby out with the bathwater when it comes to the use of traditional building materials I also believe that knowledge is power. Hopefully knowing that there are other options out there can help you make the best choice for your home.