Brick, Concrete Blocks, or Stone Walls
Brick, concrete blocks, and stone are some of the most common materials used in building the walls of the traditional above ground root cellar. Usually the cost and availability of these materials are the most important factors in determining which of these products you choose. As you probably know, bricks come in a wide variety of sizes. They are typically small and therefore easy to work with, because they are small you will need more product and your structure will take longer to construct. Concrete blocks are a good choice for making heavy-duty walls. They are usually cheaper than brick and the construction will go much quicker because of their larger size.
Concrete-block walled cellar
Building with stone or large rocks is often the cheapest option as these materials can often be found on your own property. The construction can also be more challenging since you'll need a good eye, a strong back, and lots of patience to build sturdy walls from rocks that are all different shapes and sizes. However, building with stone can also give you a huge sense of accomplishment; not only will your structure have been built from materials gathered from your own land, it will have a hand-crafted look and quality.
If you are new to building with rock and are not yet familiar with cutting the material, you will want to start with the flattest edged rocks you can find for your first layer. Choose rocks that are similar in height to start building up your wall, continuing along the full length of the wall. Fill in all the joints between the rocks with mortar. When the first course is complete, spread mortar across the top and continue building another layer. If you run out of similar-sized rock, find two that can be stacked to match the others. Stand back and look at the wall to make sure the joints are all staggered; if not your wall has more of a chance of breaking.
Mortar is a mix of cement, lime, sand, and water that acts as a bonding agent, the glue that sticks your brick, cement blocks, or stone together. Make sure you consult with professionals regarding the proper mix for your type of building project.
Building walls with brick or cement blocks is fairly straightforward; you simply stack them on top of each other, using mortar in between each block as the cementing agent. You will want to stagger the blocks so the joint of the blocks below are fully covered with a block on top, creating a stronger structure with less likelihood of water penetrating the wall.