What is Earthen floor? (How to Make It, Pros & Cons)

Adobe floors have been around for centuries. They’re simple to install, eco-friendly, and naturally beautiful. This type of flooring is made by installing two layers of floor mix over a compact substrate.

The end result is usually a beautiful, eco-friendly, and comfortable floor. However, it has some drawbacks, including relatively poor durability, vulnerability to moisture damage, and long drying times.

What are Earthen Flooring?

Earthen flooring, also known as mud or adobe flooring, is a natural type of flooring made by mixing clay, sand, and straw. Other additives may be included to improve the strength and stability of the floor mix. Earthen floors are typically laid on grade, but can also be installed over wooden subfloors.

How to Make Earthen Floors

i. Prep the Substrate

Ideally, you want your adobe floor to sit on a solid substrate to prevent cracking. As such, if you’re installing the mud floor on grade, you should ensure the earth is adequately compact.

Avoid installing your earthen floor on topsoil, which is usually loose and laden with organic matter. As the organic matter decomposes, your substrate will shrink, leading to gaps beneath the earthen flooring. This compromises the structural integrity of your floor.

Dig into the earth using a spade to remove the topsoil. Continue digging until you reach hard, compact ground that’s free of organic matter. You can use a hand tamper to ensure proper compaction.

ii. Lay the Capillary Break

A capillary break works to prevent ground moisture from creeping up to your earthen floor through capillary action. Pea gravel is a hydrophobic, natural material that’s effective as a capillary break. Filling in your adobe floor’s foundation with 10-15cm of gravel will sufficiently keep off soil water from rising to the floor above.

iii. Install Underlayment Sheeting

Laying underlayment sheeting over your capillary break provides a second layer of moisture protection. This is crucial, as vapor from evaporated soil water will still find its way through the capillary break. The underlayment material serves as a barrier against such air-borne vapor.

We recommend using 6mm polyethylene sheeting. While it’s not biodegradable, it offers excellent moisture protection.

iv. Install Insulation

The insulation isn’t mandatory but is crucial if you want an energy-efficient adobe floor. If you have a heating system installed in a room with an earthen floor that’s not insulated, lots of heat will be lost to the ground beneath the foundation.

To prevent this kind of heat loss and minimize energy wastage through the floor, install rigid foam insulation before installing your base layer of earthen flooring. For eco-friendly insulation, use perlite or pumice instead. Both of these natural minerals are non-biodegradable, thus won’t decompose to leave you with cracks in your floor.

v. Install the Base Layer

To install the base layer, prepare your earthen mix, which includes clay, sand, and straw. Then, starting from the furthest corner of the room, roughly pack the adobe mix into place.

As you fill in the base layer, make sure to get to all corners and voids. Also, use a screed guide to ensure you fill in the mix to the appropriate height/thickness. Finally, level the floor using a 2×4, before leaving it to cure.

vi. Install the Leveling Layer

Once the base layer is fully dry, it’s now time to install the leveling layer. The purpose of this layer is to achieve an even and smooth surface that’s aesthetically pleasing.

You can use the same materials as that of the earthen mix used for the base layer. However, the clay should be fine-sifted and the straws should be chopped shorter. These changes are necessary to achieve smaller particles that can be smoothened to a finer finish.

For the smoothest finish, take off straw from the mixture for this layer. However, removing a straw from the equation calls for a perfect balance of clay and sand in the mixture. A straw-free adobe mix with a poor clay-sand ratio will likely crack or crumble as it cures.

vii. Apply a Finish Coat

Once the leveling layer fully cures, you can choose to apply a layer of finishing. This can either be a thin layer of clay or a hardening oil sealer. The most common hardening oil sealer used on earthen floors is linseed oil. It works to make the top clay layer more hard-wearing, dust-resistant, and stain-proof.

Linseed oil and other hardening oil sealers (hemp oil, walnut oil) not only serve a functional role but an aesthetic one as well. They can be pigmented to enrich the final color of the mud floor.

Pros and Cons of Earthen Flooring

You may be asking yourself why you should go for earthen flooring. This type of floor has many advantages over other types of flooring such as concrete, as detailed below.

The Advantages of Earthen flooring

i. Great for In-Floor Radiant Heat

Earthen floors boast excellent compatibility with in-floor radiant heating systems. You can install radiant heat pipes before laying your base layer of adobe mix. This will help keep your home and floor warmer, especially during winter.

ii. Soft Underfoot Feel

Unlike concrete which has a hard and uncomfortable underfoot feel when you stand on it for a prolonged duration, earthen flooring has a soft underfoot feel.

iii. Eco-Friendly Flooring Option

Earthen floors have a minimal environmental impact due to their low embodied energy. What’s more, this type of flooring has very low amounts of VOCs (Volatile Organic Compounds) that may cause respiratory problems.

iv. Visually Appealing Flooring

Earthen floors boast unmatched natural beauty. The red-brown hue of clay will add a touch of warmth to your home. Pigmented sealers also build upon the floor’s visual feel.

v. Affordable Flooring

When compared to other types of flooring, mud flooring is relatively economical. The raw materials (clay, sand, gravel, and straw) don’t cost a lot and no special tools are required for installation. Also, the fact that you can easily do DIY installation should save you on installation costs.

vi. Easy to Install

It’s easy to lay earthen flooring once you prepare the substrate and the clay-sand-straw mix. Due to its relatively simple installation process, you can undertake earthen floor installation as a DIY project.

The Disadvantages of Earthen flooring

Despite the above benefits of adobe floors, it also has some disadvantages. You’ll have to look out for the following cons if you’ll be installing earthen flooring in your home.

i. Prone to Moisture Damage

Earthen floors, when properly sealed, have decent moisture resistance. However, prolonged contact with water will cause extensive damage to this type of floor, as the water eats through the sealer. It’s, therefore, advisable to avoid the installation of earthen flooring in wet rooms like kitchens and bathrooms. 

ii. Not Durable

Earthen flooring that’s installed over a solid and compact grade substrate boasts decent durability. However, it still isn’t as durable and hard-wearing as comparable types of flooring, such as concrete. Heavy point loads will likely leave dents and gouges on your mud floor.

iii. Long Curing Times

A newly installed, the wet earthen floor will typically take up to 14 days to fully cure. This is quite long, considering that you can walk on some types of floors (like vinyl or hardwood) immediately after installation. Nevertheless, you can install dehumidifiers to reduce the curing time of your wet adobe floor by up to 7 days.

Earthen Flooring Problems

Here are some of the problems that you should be on the lookout for if you’re looking to install earthen flooring in your home.

  1. Cracking– this is most likely to occur due to irregular curing. To ensure that your earthen floor cures evenly, ensure that all batches of floor mix used for the floor have similar consistency/wetness.
  2. Odor- you’ll notice an unpleasant odor when you use hardening oils like linseed oil to seal your adobe floor. To prevent this issue, use raw linseed oil instead.

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