Earth Mortars

Earth mortar as a bonding agent

Our earth mortar is manufactured from natural, clayey soil with no additives or hardeners. Earth mortar is the most sustainable alternative to using lime-based mortars and deliver a near-zero carbon footprint from cradle to grave. Apart from the impressive environmental statistics that our earth mortar carries, there are other benefits from using earth mortar and these include regulating moisture and thermal efficiency.

Our earth mortars are increasing in popularity and becoming more widely accepted as a sustainable, eco-friendly alternative to lime-based mortars and are comparable in cost to ready-mixed lime mortars available. Our earth mortars have been developed as a bonding mortar for cob blocks and cob bricks but can also be used as a base-coat earth plaster for wall applications, primarily though our earth mortar is used for building cob block walls.

earth mortar earth and clay mortars earth mortar blocks — Newly laid cob bricks

earth mortar earth mortars earth bonding mortar — Cured earth mortar

Earth mortar ingredients

Our earth mortars consist of aggregates, sands, clays and chopped straw. When unprocessed, raw material reaches our depot it always contains an element of moisture. The moisture levels vary, depending on the time of year and source conditions. To ensure that we can produce a suitable end product, the raw material must be dry and free of all moisture. Our drying processes require no firing, ovens or fans……it’s simply stored under cover for the sun and/or breeze to encourage moisture evaporation. When the stored material is dry, it is transferred onto a large sieve to separate the stones and larger gravels.

The principal ingredient for earth mortar is clay. Sufficient clay content will ensure greater adhesion during application and a strong set when cured. Aggregates play an important role too, the inclusion of these provides strength, bulk and reduces shrinkage during curing. Our earth mortars contain gravels no larger than 10mm + coarse/medium/fine sands. The addition of chopped straw acts as a binder to the earth mortar and further reduces the likelihood of shrinkage during drying.

Reusable, recyclable and zero-waste

Given that our earth mortar is made from 100% natural materials, end-of-life disposal is, by far, as simple as redistributing it back to the ground where it first originated. But what about during construction? Earth mortar is delivered as a dry-mix and therefore requires water to make it into a usable bonding agent. Once sufficient water is added, the earth mortar becomes a liquified medium ready for use. If too much water is added, then introduce more dry-mix to achieve the desired consistency. If too dry, then add more water. During the build itself, there will inevitably be excess earth mortar to the cob block joints and/or dropped earth mortar at the wall base. This can be collected, reconstituted and used again or stored in a sealed container/air-tight bag in readiness for another day, reflecting the fact that earth mortar does not have a shelf life.