The art of adobe brick building has been a time-honored tradition since ancient times. Many of the structures made from adobe bricks still stand today, and it’s a trusted method of building in places worldwide.
Unfortunately, even if you know the theory of how to make adobe bricks, it isn’t as easy as it looks. And unless you’re using an adobe brick machine, there’s a real need to be watchful at each step to ensure you’re getting it right.
Making adobe bricks begins by selecting a suitable soil mixture comprising clay, sand, and straw to bind them all together. These ingredients are mixed with water to achieve the desired consistency, and this mix is then poured into the brick forms and left to dry.
In the rest of the article, I’ll expand on the steps involved in the brick-making process. So hopefully, by the end, you’ll have the necessary know-how to successfully make adobe bricks.
Earthbag building is another sustainable building method that might interest you, check out our article showcasing 20 amazing earthbag homes.
Step 1 – Gather the Tools
First, gather the tools needed to complete the job. The tools needed are:
- Large metal trough: To mix all your ingredients.
- Wooden forms: For pouring your mix.
- Wheelbarrow: To carry your mix.
- Screed: For leveling the top.
- Pot sprinkler: For watering the mix on brick forms.
- Rake: To mix all your ingredients in the trough.
The wooden form is the most important of all these tools and determines the finished size of the adobe bricks.
Choosing the right soil is always a crucial step in the brick-making process. The right soil is a mixture of clay and sand that can be sourced locally.
There can be some slight variation in how these raw materials are used. Here are two such options to help explain which materials to use and in what proportions:
- Casual option: A 70:30 mix of sand and clay + Water + Straw/Hay/Grass
- Standard option: A 70:30 mix of washed concrete sand and clay-rich soil + Water + Straw
The standard option is preferable for more serious projects. This adobe brick recipe has the perfect soil mix to produce the highest quality bricks.
Step 3 – Preparing the Mix
Mixing the raw materials is the next important step. When preparing the mix, be mindful of the proper ratios and add all materials gradually.
Proper mixing at each step is essential, and a rake will be helpful, especially if you’re using a trough to do all the mixing.
For the standard option:
- Add four buckets of water in a metal trough.
- Follow this up with two buckets of straw and mix them with a rake.
- Now fill the trough with three to four buckets of clay-rich soil and repeat the process.
- Finally, add seven buckets of washed concrete sand and mix with a rake.
Mix all materials until you get a homogenous mixture that is not too hard or too soft in consistency. Ideally, the mixture should be pliable and workable.
You will also notice some lumps in the mixture, which is normal when such large quantities are mixed together.
Just ensure you manually check the trough for these lumps and break them down with your bare hands.
It’s time to fill the molds when your final mix is ready. To do this:
- Place your wooden forms on a flat surface and pour the mix into them. You can use a wheelbarrow to help with the carrying and pouring part. Ensure you’re not filling them to their total capacity, as you risk tipping them over.
- Some prefer to soak their brick forms in water before adding the mix, which helps the bricks come out easily when ready.
- Pack the mix perfectly into the wooden forms, leaving no air gaps or pockets. Use a screed to remove the excess mix and level them as needed.
- Mud bricks are susceptible to cracks when placed to dry in hot and breezy conditions. Therefore, spraying a light mist of water with the help of a pot sprinkler on top of the bricks is advisable.
- Follow this by lightly leveling out the surface using gloves. There’s no need to level the top surface completely. In fact, it’s better to have a slightly rough surface; this will help the bricks to grab the mortar more efficiently.
This brings us to our last step, which is drying the bricks. Once the mix is poured and lightly dried for about 24 hours, remove the forms and flip the bricks. Flipping the bricks is important and will allow them to dry faster.
Generally, the longer you let them dry, the stronger they will be. There’s no perfect timeline, but a week is usually enough for most Adobe bricks to dry completely.
The primary raw materials used in making adobe bricks are clay, sand, straw, and water. Clay and sand are the most consistently used materials, while straw is occasionally replaced by hay or grass.
Several factors, like climate, humidity levels, and airflow, determine the drying time of Adobe bricks. Although on average, it takes about a week for adobe bricks to dry completely if placed in a dry, breezy location.
However, this time can be reduced to four or five days in very hot and arid climates.
Is Adobe Stronger than Concrete?
Adobe is not stronger than concrete. Even though adobes have been used for centuries, they still lack the compressive strength of concrete. Concrete is a more complete and durable building material for constructing structures requiring more stability. Adobes also have their place but are less strong than concrete blocks.
You would always keep your adobe bricks away from any substance or chemical that can harm the surface of the adobe.
- Some chemicals can disrupt the soil from which adobes are made, and it is these chemicals that you should be aware of.
- Oils and greases are other culprits that can harm the bricks by attracting dirt or other debris, thus making cleaning difficult.
- Moisture is also a problem for adobes and can harm the structural integrity of the bricks causing them to wear down over time.
Under the right conditions and with appropriate maintenance, adobe bricks can last for centuries. That said, even without proper maintenance, these bricks can easily last for at least thirty years.
Typical maintenance of Adobe bricks involves occasional plastering and a slurry wash if and when required.
It is to be noted that factors such as exposure to excess moisture, temperature fluctuations, and extreme weather conditions can also directly impact the lifespan of these bricks.
What Happens to Adobe Bricks When It Rains?
Adobe bricks are incredibly resilient and can withstand rain without washing away. However, newer bricks can be vulnerable when exposed to heavy rainfall.
The older the bricks are, the more they are baked in the sun, making them harder and more durable to withstand extreme weather.
But waterproofing measures are still necessary and can mitigate any negative effects of rainfall. This is particularly important in areas with high rainfall.
The natural composition of adobe bricks makes them eco-friendly, especially compared to other building materials.
The raw materials used in adobes are natural, non-toxic, and biodegradable, making them a preferred choice for sustainable construction.
Adobe bricks also have high thermal mass and retain heat to reduce energy consumption.
R-value depends on the thickness and density of the bricks, but generally, the R-value of adobes falls between 0.2 – 0.3 per inch.
The type of soil used is also an underrated factor affecting these bricks’ R-value. Typically, adobes have a lower R-value than traditional building materials like wood.
It is possible to paint over adobe bricks. However, there are some precautions you need to take:
- Before painting, clean your bricks to remove any dirt and apply a primer. Using a primer will ensure better paint adhesion to the bricks’ surface.
- Choosing the right paint is also important because certain paints may not work well with adobes; this is where a professional painter can guide you in the right direction.
Final Thoughts On How To Make Adobe Bricks
The adobe brick-making process involves mixing clay, sand, straw, and water together in the correct ratios.
Once the desired consistency has been achieved, the mix is poured into forms and left to dry for about a week.
Following the above steps to the tee will ensure that your project goes smoothly and you make the highest-quality bricks.