Will earth block and adobe walls wash away in the rain?
This is probably the most common question. The answer is no. A well-designed mix resists degradation and will remain durable for centuries. At any point, the building can be plastered, with the same material the bricks and mortar is made from, to further enhance durability. The use of a small percentage of stabilizer, such as Portland cement or lime, can be added to increase the resistance to moisture in wet climates. Typically a roof overhang of just 1 foot is sufficient to protect the walls from rain. We have many homes in New Zealand's wet climate, where it rains 5 out of 7 days 8 months of the year.
Do earth block and adobe walls get dusty?
No. Well built earthen walls are strong and durable with a smooth and clean finish. Clay based plasters give a brilliant finish that are dust-free, sponge-wipe cleanable, and rainwater shedding. For fun, we have thrown an egg at a earth plastered wall and wiped the wall clean with a sponge.
How does earth block and adobe construction compare to conventional building techniques?
An earth block and adobe building is not only healthy for the individual, but also for the planet. Soil, earth block’s primary ingredient, is a renewable, non-toxic natural resource. Earth block and adobe walls are breathable, soundproof, bug-proof, fireproof, and even bulletproof! Requiring less transportation of materials than conventional construction methods, earth blocks and adobe have a lower embodied energy than conventional building materials. Energy savings are immediate with thermal mass equating to lowered heating and cooling requirements. Earth block and adobe buildings can last for centuries. Ancient earthen structures stand today in many parts of the world. The average expected life span of a wood frame building is about 70 years.
What does it mean to have a ‘breathable’ wall?
A breathable wall is able to absorb and release water vapor. Water vapor molecules are no larger than air. Like human skin, the water vapor passes in and out, but does not transmit water molecules. This transpiration of vapor helps to regulate and modify heat and humidity. This benefit reduces the need for mechanical systems to maintain human comfort levels. Clay maintains an equilibrium moisture content. If there is too much humidity in the air, the walls will absorb water vapor. Conversely, if the air is too dry, the walls will release moisture. Human health is optimized at humidity levels between 40% and 70%. Low humidity levels will dry out the trachea, contributing to respiratory issues. High humidity levels promote mold growth, again not beneficial to human health.
Cement stucco and other synthetic materials, such as closed cell insulation and paint, applied to earth block and adobe walls will hinder their breathability. Lime or clay plasters maintain an earth block and adobe wall’s breathability.
What is thermal mass?
Thermal mass is the ability of a material to absorb and store thermal energy. This creates thermal inertia that requires a much larger input of energy over time to change its temperature. This is sometimes referred to as a “thermal flywheel”. Therefore, if a wall is cool from a relatively chilly summer night, it tends to stay cool well into the day. Conversely, If a wall is warmed by the afternoon’s winter sun, then it stays warm well into a cold winter night. Walls that have low thermal mass, such as conventionally framed walls, do not have these properties and are easily effected by a change in temperature. Earth blocks and adobes, on the other hand, will “flatten out” or buffer large temperature swings with their thermal mass capabilities and significantly decrease the need for additional heating in winter or cooling in summer.
We realize there are many more questions and answers that are listed here. And fortunately there are many resources of information. Visit the links below to find the type of information you are seeking.
Thermal Mass and Insulation
Earthen Walls in a variety of climates
Appropriate mixes for earthen blocks
"Earth walls give a living environment like no other building material. It's difficult to explain in words because the effect is a subtle feeling you get by being in them; serene, warm, solid, less noise, healthier, secure."
Owner of an earthen home