How to Build a Block Wall without Mortar
Building a garden wall, a planter, mailbox enclosure or even an outdoor kitchen, can be as easy as stack and stucco with a surface bonding cement.
The construction process is quick and easy for even the novice do-it-yourselfer, with professional results.
A surface bonding cement is a special fiberglass reinforced stucco that is simply troweled over the surface of a dry stack block wall.
A surface bonding cement can create beautiful stucco walls that are stronger and faster to build than traditional block and mortar construction. Every block wall, whether structural or non-structural, requires a solid footing or slab as its base.
High-strength cement is the recommended product for footing construction because of its high strength and rapid strength gain. Footings should be a minimum of twice the width of the concrete block, a typical 8 x 8 x 16 block would require a 16 inch wide footing.
The footing depth should extend below the frost line. It is important to check local building codes for construction requirements in your area.
A surface bonding cement can be successfully mixed by hand or machine mixed. The size of your project will often determine which method you choose.
Hand mixing can be done in a mortar tub or wheelbarrow with a mixing hoe, and is suited for small projects. When working with surface bonding cement, rubber gloves and safety glasses should always be worn during mixing and placing procedures.
Each 50 pound bag of a surface bonding cement requires about a gallon of water. Additional water can be added in small amounts, to achieve a workable mix.
Adding liquid cement color to standard white or gray surface bonding cement can add a decorative stucco finish. One 10 ounce bottle of liquid cement color will color up to two bags of 50-pound bonding cement.
To achieve a consistent color throughout the mix, the liquid cement color should be blended into the mixing water before adding it to the mix. Using the same water to color ratio will help maintain color uniformity from batch to batch. This is especially important when working on large areas.
The proper consistency is achieved when the wet surface bonding cement will hang on a trowel held at a ninety degree angle.
To get started, it is important to stage the first course of block.
Snap a chalk line on each side of the block wall as a reference line to ensure the corners are square and the wall is straight.
Then, remove the block and lay a one-eighth inch bed of surface bonding cement on the footing. This will not only bond your wall to the footing, it will also keep the first course level if there are slight imperfections in the concrete footing.
The surface bonding cement mix should be workable but firm enough to support the weight of the first course.
Because there are no mortar joints in this construction technique, the first course of block will determine how level and square the wall will be.
Now, set your bottom course. Check your alignment and level every third to fourth block. Once your first course is set, dry stack the remaining block in a running bond pattern to the desired height.
All corners should use an interlocking pattern. Before applying surface bonding cement, thoroughly dampen the block wall with water. Dry block will draw the water from the mix, making it difficult to finish and can cause inconsistent color and cracking, especially in hot temperatures. Then, apply a consistent one eighth to one-quarter inch coat of surface bonding cement to both sides of the block.
Use a square finishing trowel held at a 45 degree angle and work from the bottom of the wall to the top.
Popular textures such as heavy lace, light lace, dash and smooth finishes are easy to achieve with a little practice. It is recommended that you check your surface bonding cement color and practice your texturing technique on a block or a sheet of cement board, prior to attempting to finish a large wall.
One 50 pound bag of surface bonding cement will cover approximately 50 square feet at one-eighth inch thick. The coverage may vary, based on the texture and thickness of the cement application.
Once your wall is completed, water cure the entire surface with a fine water mist. This is especially important for color consistency and to prevent surface cracking.