An Earthen home can be fun to build and super cheap, but not if you have to repair or reconstruct the house every year due to water damage. Many people want to know are adobe bricks waterproof and they are not, but they can be.
I researched all the methods available and implemented a few on my adobe home and I share my experience and knowledge below to help others.
Ways to make adobe bricks waterproof include firing the bricks in a homemade kiln, adding Portland cement to make semi-stabilized (3-6%) or stabilized (7-12%) bricks, covering walls with 3 coats of mud (cement optional), sealing with paint or epoxy, covering with 2 coats of concrete, stucco spray. The most effective is long roof overhangs.
1. Adobe Brick Kiln
Mud bricks can be fired in a homemade kiln for 12 – 24 hours to create waterproof adobe bricks. The kiln can be built using your existing adobe bricks and I learned how from a YouTube video that I included below.


Learn how to build your own with the best how to book on Amazon here.
The advantages are:
- Waterproof (unless you don’t have enough clay content and don’t fire them for long enough, like in my situation. I only did it as a test though as I did not want to use fired bricks).
- Stronger bricks that would be better on the lower rows of the walls where there can be more rain splash back or moisture wicking up from the ground.
- Faster and more complete drying so no shrinkage and settling after the wall is completed. My bricks, the ones that survived the wet season, were outside under a tarp for almost a year while I returned home to Canada. So they were perfectly dry.

Building an adobe brick kiln and firing bricks disadvantages include:
- A lot more work. This project is already very labor-intensive and the prospect of more work will put some people off.
- If you have low clay content in your mud the finished fired product may be weaker than the original (this happened to me).
- When natural, not covered, sealed, or fired, the bricks absorb moisture and help to reduce the humidity to a more comfortable level.

2. Add Concrete To Adobe Brick
Add concrete to adobe brick to make it waterproof as semi-stabilized or stabilized. Well, actually add cement. The cement to use us Portland cement. Adding 3 – 6% of Portland cement by weight produces a semi-stabilized block and 7 – 12% a stabilized one.

Semi-Stabilized Advantages
- Most of the benefits as stabilized with half the cost.
- Water-resistant
- Stronger
- More durable
- The finished color looks less like a concrete wall than with more cement.
Semi-Stabilized Disadvantages
- More expensive
- More work
- Less environmentally-friendly
- Looks more like a traditional house rather than a natural earthen home
Stabilized Adobe Brick Advantages
- Waterproof
- Much stronger which produces less cracking is due to movement caused by wind, earth, and bumps.
- Very durable
- Less shrinkage and therefore fewer cracks during drying
- Potentially save time with fewer required
Stabilized Adobe Brick Disadvantages
- More expensive
- More work
- Less environmentally-friendly
- Looks more like a concrete home unless it is painted, which adds cost and labor
3. How To Seal Adobe Bricks
You can seal the bricks with:
- Two coats of natural tapioca powder mixed with water for the interior and you can see the instructions in my article here.
- Two coats of glue and water for the interior and you can read more about painting the walls in my article here, and sealing them here.
- Two coats of 1 part linseed oil and 3 parts paint thinner for the exterior.

4. Paint/Epoxy
The adobe bricks can be protected with a couple of coats of paint on either the inside or the exterior.
The below is an excerpt from one of my articles where you can learn how to paint adobe bricks, just click the source link below the quote.
There are two main types of paint you can choose from: these are water-based and oil-based. Acrylic and latex are water-based paint, while alkyd paints are oil-based, and both interior and exterior paints come in both types.
I used (and by I I actually mean my better half, Air. Yes, Thais go by their simple single word nicknames) two coats of clear epoxy on the exterior walls and on the interior walls near any water sources such as the shower and toilet areas.
This allowed every to see the wall construction and we think it is much more unique and beautiful.

Learn through my articles can you paint them here, advantages and disadvantages, how many you need, and 10 best anchors for a strong house.
Scott Boyd
5. Mud
This is the cheapest and easiest solution, but unless you stabilize the mud with Portland cement it won’t be anymore waterproof than the bricks. So this method requires overhangs (discussed below) or the addition of Portland cement (section 2).
Fully stabilized provides a more waterproof wall system that can be painted or left the natural color. You can also get creative and add materials to change the color such as ground-up charcoal for a darker color.

You will need two or three coats of mud and you can apply the mixture a number of ways:
- Bare hands. I prefer this method but many of you will want gloves if using Portland cement as it will dry your hands and also act like sandpaper and wear down the skin.
- Hawk and trowel. Some of you tapers know what I mean. This is a super-easy way to get a smoother finish if that is the look you are, well, looking for. You can see photos of them here on Wikipedia.
These are available at most local hardware stores in the drywall and paint section. - Concrete trowel and bucket. Similar to above but the trowel is much more head duty and has rounded edges that will make it much easier for folks not in the drywall or concrete trades.
- A combination of bare hands, perhaps for the first coat, and then one of the other options to provide a smooth finish.
TIP: Build overhangs asap and allow the building to dry as long as possible so that all the settling is complete before adding the mud wall. Otherwise, you will have future cracks to repair.
Mud waterproofing advantages:
- Dirt cheap, pun intended.
- Super easy for homeowners to make repairs to future cracks.
- Hides your attractive block walls, but with another natural and warm look.

Mud waterproofing disadvantages:
- Not waterproof without adding Portland cement, which turns it a lighter, less attractive color. Also not as environmentally friendly as the process to manufacture cement if very energy-consuming.
- More layers are required as the clay in the mixture shrinks and cracks. Expect to apply three or more coats.
TIP: Scrape the walls with a farmer’s hoe, square mouth shovel, hammer, or other to know off the larger bumps. Don’t worry about making the wall smooth as a rough wall will hold the mud better.
TIP: Mix the mud as close as possible to the work area. Trust me, by now you are getting tired of lugging heavy buckets around the construction site.
6. Concrete
This is similar to the Mud section above expect that you either use only concrete or a mud mixture with a higher percentage of Portland cement.
It seems like a shame to cover beautiful adobe bricks with concrete, even mud really. I prefer the exposed bricks with a couple of coats of epoxy. Otherwise, the house looks like any other concrete cover structure and I want to show off the adobe house.
Everyone here in rural Thailand who sees my little building loves it, wants one, and says how strong the walls are.
TIP: Mix small batches in a wheelbarrow to start. After a few batches, you will have a better idea of how much you can mix for each batch without running out of time and having to waste cement due to it setting up (getting hard).
7. Stucco
Once again I think it would be a shame to hide your beautiful walls with so much character and showing off your work, but it is an option that I am sure some folks will do. Call a local contractor to get ballpark per square foot pricing for straying the building.
Stucco advantages:
- Fast! Unless you have a multi-story they can spray it in an afternoon.
- Can add texture, but you can do that with the other methods too.
Stucco disadvantages:
- Hiding your beautiful walls.
- Harder for most homeowners to repair when the inevitable cracks appear.
8. Roof Overhangs For Adobe Bricks
This is a method that everyone should incorporate into this type of home construction. Here in Thailand houses are often build eight feet into the air for covered living space below.
And then they usually have even much more covered areas as they live outside and sleep inside.
These overhangs protect them from the sun and monsoons this same strategy works great for adobe houses. I build ours using bamboo and eucalyptus poles and tin and thatch roof panels. Advantages include:

- cheap.
- tin roof panels are easy to cut with snipes. Cheap galvanized panels without paint look crappy so go for the colored ones with a nice profile.
- thatch roof panels are installed with wire and pliers or string, they look amazing, and provide a high R insulation value.
- one person can do all the work.
If you want a complete easy to follow guide with photos and tips to make adobe bricks then check out my article here.