Block Wall Specifications


For strength and permanence, masonry such as a block wall, is a common construction option. A freestanding block wall can serve as an enclosure or barrier and must be constructed with the appropriate concrete masonry units (CMU) to ensure longevity. For any concrete block wall, careful planning is necessary and you must consult local building codes before construction begins. Local codes have specific standards for masonry walls more than a few feet high, which take the weight, soil type and other factors into consideration. Adhering to all specifications is important for project approval and crucial for a strong and long-lasting block wall.

Foundation/Footing Specifications

  • A correctly constructed footing is the beginning of a strong concrete block wall. Typically, this poured concrete foundation must be twice the width of the wall and installed at least 12 inches deep or as deep as the frost line in your area, as determined by your local building codes.

    In average soil conditions you can pour the concrete footing to the required dimensions, in the bottom of a trench on firm/tamped soil. Since you can expand the trench wide enough to provide a work area, without much additional labor, construction of the wall can began on top of the footing, below ground level.

    In harder to dig, firmer soils, it's less labor intensive to dig the trench the required depth and just wide enough to accommodate the width of the footing, then fill it up to ground level with concrete. The wall is then constructed above ground since there's no room to work in the trench.

Reinforcement Specifications

  • Before concrete can be poured for the footings, lengths of steel reinforcement bars (often referred to as rebar) must be laid in the trench to reinforce the block wall foundation. Local building codes determine the correct diameter of the steel bars to be used.

    It's important to reinforce masonry walls more than 4 feet high, both vertically and horizontally, to avoid any shifting or collapsing. By inserting steel reinforcement rods through the hollow cores of the stacked concrete blocks, spaced every 4 feet, the wall is strengthened vertically. Laying continuous lengths of truss-shaped joint reinforcement over the tops of the blocks, every second course, strengthens the wall horizontally. The cores must then be filled with grout to lock the steel rods and blocks together while laying the courses.

Material Specifications

  • Mortar is the glue which holds block masonry walls together and must meet standard codes. Type S mortar is classified for use in structural applications and required by most local building codes. Prepackaged bags are available, but less economical for large jobs where mixing your own formulation may be desired. Consult your local building codes for the correct formula of Portland cement, lime, sand and water for your mortar.

    The CMUs you use to construct your wall must comply with the American Society for Testing and Materials (ASTM) C90 standards to be approved by most local building inspectors. Stretcher blocks are a common CMU used to make up the bulk of a block wall and have standard dimensions of 8-by-8-by-16 inches. Shorter half blocks measuring 8-by-8-by-8 are used as needed to avoid cutting the longer blocks, to complete the wall construction.

    The grout used to filled the hollow cores of your stretcher blocks is a formulation of mortar thinned with water and must follow ASTM guidelines.

Related Searches


  • Photo Credit wall image by Bartlomiej Nowak from
Promoted By Zergnet


You May Also Like

  • About Concrete Block Walls

    Concrete block walls are everywhere, and they are used for everything from building homes and buildings to surrounding or marking off landscaping....

  • Concrete Block Wall Problems

    Concrete block walls are some of the strongest walls available to the construction industry. However, they may experience many problems over their...

  • How to Install a Stackable Block Wall

    Block walls make for great sides to planters, elevated gardens or retaining walls. The hardest part of installing a stackable block wall...

  • How to Fur Out a Block Wall

    Attaching furring strips to a concrete block wall requires a special tool and specific screws. The dual action of a hammer drill...

  • Concrete Retaining Wall Specifications

    A hopelessly hilly or uneven yard can make setting up a garden, building a patio or completing other types of landscaping projects...

  • Block Walls Vs. Precast Concrete Walls

    All concrete is made of cement, water and aggregate, rocks varying in size from sand to gravel. The cement and water make...

  • Concrete Block Specifications

    Concrete block construction is labor intensive. Use concrete blocks to form long-lasting, low-maintenance and fire-resistant structures, walls and foundations. Weatherproofing concrete blocks...

Related Searches

Check It Out

22 DIY Ways to Update Your Home on a Small Budget

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!