Block Walls vs. Cast-in-Place Concrete Walls

Jump-To:

• What Are Block Walls?
• What Are Cast-in-Place Concrete Walls?
• How Block Walls Are Built
• How Cast-in-Place Concrete Walls Are Constructed
• Applications of Block Walls
• Applications of Cast-in-Place Concrete Walls
• Benefits of Block Walls Over Cast-in-Place Concrete Walls

Block walls are structures containing standard concrete blocks that can take on various shapes and sizes. The production of cast-in-place (CIP) concrete walls involves casting concrete and a mix of aggregates into a mold at the worksite.

While both types are useful for commercial and residential applications, they each have unique characteristics and advantages that work well for different purposes. Use this guide to compare concrete block walls vs. cast-in-place concrete walls and determine which one is better for your construction project.

What Are Block Walls?

Block walls contain Concrete Masonry Units (CMU) that can be stacked to form a retaining wall or part of a building. The blocks’ sizes may vary based on the design parameters and regulations from the engineer, but they’re all the same type of block. Each block contains standard concrete, a mixture of gravel and sand and Portland cement as the adhesive.

Here are some of the characteristics of concrete block walls:

• Lightweight: Concrete blocks are hollow on the inside, allowing them to maintain their light weight so that walls are easy to install.
• Flexible: Concrete blocks feature fine grains of sand and smaller aggregate materials to accommodate the specific molding. Due to their high compression strength, they can hold a substantial amount of weight on top of the foundation.
• Reinforced: To increase its tensile strength, the contractor could install reinforcing bars after construction through the block’s hollow parts.

A block wall features concrete blocks in the following unit configurations:

• Stretcher: A stretcher unit is a type of block that fits in the primary portion of the wall, where adjoining units cover both ends.
• Sash: This type of concrete block features slots cut on the surface’s flat ends to use around door and window openings to expand the space.
• Single corner: This configuration has a backward “L” shape, and it features one cornered end to accommodate the end of the wall, where a stretcher block’s side may be vulnerable in a structure.
• Double corner: A double corner CMU has a “U” shape and is used to stack blocks to build vertical structures.
• Cap: This unit is a dense, thin block of concrete that goes on top of a block wall to protect the open spaces.

What Are Cast-in-Place Concrete Walls?

CIP concrete walls contain ready-mix cement that goes into removable molds built on site. The wall system features an exposed structure where the interior walls are also part of the exterior facade. Windows, masonry or cladding material often fills any penetrations or openings within the walls of the building.

The structural systems of CIP concrete walls include:

• Vertical load resisting system: The vertical load system guards against the pull of gravity to maintain the building’s structural integrity. As a result, the force of the lateral load transfers to the ground beneath the foundation to prevent sinking. This system consists of the floor, the columns and the walls of a building to provide horizontal and vertical framing protection.
• Lateral resisting system: The lateral load system protects the structure from damage due to harsh winds or seismic activity. This configuration features movement-resistant and braced frames, shear walls and tubes. Builders most often use it in high rise buildings that need additional support.

When professional concrete builders create CIP concrete walls, they must follow the strength, serviceability and durability requirements of the building code for the American Concrete Insitute (ACI). Constructors must design and build these structures to enhance the overall integrity to provide a safe, durable product for business managers and homeowners.

How Block Walls Are Built

Concrete blocks are available in various shapes and sizes that can accommodate the wall’s function and configuration. Besides these units, manufacturers use the following components to create a concrete block wall:

• Foundation: The solid foundation of a block wall is usually made from poured concrete to stand up properly. Create a foundation with the proper size and depth, accommodating the dimensions and necessary supporting weight. A freestanding concrete block wall needs a more substantial foundation that goes under the frost line.
• Mortar joints: Mortar connects each row of blocks. For maximum strength, masonry professionals can construct concrete block walls so that the vertical joints are staggered.
• Reinforcement: Manufacturers use vertical and horizontal support to hold a freestanding block wall to prevent stress that could ruin the wall’s integrity. Wet concrete and steel rebar provide vertical reinforcement, while horizontal support involves setting reinforcement strips made of metal into the mortar while still moist.

An expert in the masonry industry will follow these steps to create a block wall using CMUs:

1. First, they design the layout of the concrete block wall’s foundation with stakes and masonry string.
2. Once they know where the foundation is going, they excavate the ground to create the foundation using a shovel in warm climates or heavy equipment in cold climates.
3. They pour the foundation of concrete into the cavity around the sides of the trench that they excavated.
4. After the foundation has adequately cured, they may use a chalk line to create a line that shows where the cement wall will go on top of the foundation’s surface. Then, they apply a thick layer of mortar onto the foundation inside the outline and set up the first cement block row over it.
5. They lay down the subsequent courses of blocks after the first one, and add reinforcement while working upward.
6. Finally, to finish the job, they install cap blocks by laying down mortar, embedding reinforcement strips made of metal and putting solid concrete caps on top.

How Cast-in-Place Concrete Walls Are Constructed

Cast-in-plate concrete walls arrive at the worksite in a soft, uncured state, usually in a cement truck. A chute sticks out from the back of the truck to the form where the concrete will cure. An expert in the masonry industry could construct CIP concrete walls by following these steps:

1. First, the client needs to indicate the appropriate location for the structure.
2. Once they know where to lay the foundation, the builder removes debris, plants or soil that could hinder the integrity of the building before pouring the concrete.
3. After clearing the area, the builder can lay out and excavate for the footings.
4. Then, they place short-term forms or insulated concrete forms in the ground.
5. Before pouring the concrete, they add steel reinforcement bars throughout the wall.
6. Finally, they pour in fresh concrete and allow it to cure for at least 24 hours.

Applications of Block Walls

Block walls are common in commercial and residential construction projects because of their versatile design and exceptional durability. You can use concrete block walls to accommodate the following applications:

• Security barriers: Concrete blocks can go side-by-side or stack on top of each other to create a blockade and prevent cars and pedestrians from entering a designated area. This wall can provide security at a special event, construction site or scene of an emergency without needing to hire additional personnel.
• Retaining walls: Walls made from concrete blocks can keep water and debris away from a building. For your application, you need a retaining wall built by a certified retaining wall contractor to maintain your structure’s stability. Retaining walls are lightweight and durable, so you can easily install an engineered retaining wall on your commercial or residential site. Retaining walls with decorative concrete blocks also create a timeless appearance for the property.
• Residential buildings: Concrete blocks can adequately insulate a home from both outdoor temperature and noise pollution, all while maintaining the look of the house. Residential buildings made from concrete blocks offer cost-effective protection against hurricanes and harsh rainstorms in coastal areas.
• Commercial buildings: Due to the durability and structural integrity of concrete block walls, you can be confident that your clients and their employees will be safe. Concrete block walls can provide a high return on investment (ROI) when you use them to construct a commercial building. Commercial buildings with concrete walls also comply with fire and safety regulations because of their resistance to fire.

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Applications of Cast-in-Place Concrete

Builders design CIP concrete walls with several unique decorative aggregates to enhance the structure’s visual appeal, depending on the application. Most of the time, contractors tend to use cast-in-place, or site-cast, concrete for their:

• Basement walls: CIP concrete walls are common for basement construction because of their structural integrity and resistance to moisture and weather damage.
• Concrete slab foundations: Along with basement walls, CIP concrete can also be suitable as concrete slab foundations. The horizontal framing can protect against gravity loads and prevent buildings from suffering from earthquake damage.
• Parking structures: Builders can construct parking structures using a one-way CIP slab and several beams for support. The vertical framing of the beams can lighten the structural load of the building.
• Beams: CIP beams for building structures, such as parking garages or apartment buildings, are wide and insulated to protect the structure against fire and weather damage.
• Columns: CIP concrete columns can ease the burden of the structural load of your building. When mixed with colorful aggregates, they could also improve the design of a building.
• Retaining walls: Even though site-cast concrete walls are traditionally for the basement, the same techniques that professionals in masonry use for below-grade walls can apply to applications that are above grade. Constructors add steel, aluminum or wood paneling to improve the natural insulation of the material. These walls also have reinforcement steel bars that enhance their tensile strength.
• Roofs: A reinforced cast-in-place concrete roof can increase the durability of a structure against weather damage, such as tornadoes, hurricanes and earthquakes.

Benefits of Block Walls Over Cast-in-Place Concrete Walls

Block walls offer the following benefits for any residential or commercial structure:

• Moisture resistance: Concrete block walls are ideal for humid or wet climates because of their ability to resist moisture. These durable walls are resistant to damage that comes from humidity. Unlike wood structures, concrete doesn’t rot or grow mildew when it stays wet for an extended time.
• Weather resistance: Besides excessive moisture, concrete homes can also withstand harsh weather conditions, such as high winds, hurricanes and tropical storms. Since concrete is fireproof, it can also act as a firewall between rooms and surrounding buildings.
• Eco-friendliness: Block walls use recycled, sustainable materials that are safe and often locally sourced, such as water, gravel, rocks and sand. You can also use these blocks again if the building ever has to be demolished. Since the blocks are natural insulators, they can also help reduce the use of energy in a building to cut down on utility costs and provide a comfortable environment.
• Ease of installation: Concrete blocks are lightweight, which can ease the heavy manual labor burden on a construction project. Since concrete block walls are easy to install, you’ll save time and money during construction. You don’t have to bring wet concrete to a site like you would have to do for cast-in-place concrete, and instead of using a form to mold them, your components are ready to use once they arrive at the site.
• Cost-effectiveness: You also don’t need to use specialized equipment to put CMUs in place, and it’s easier to install it yourself. If the construction project isn’t near a concrete plant, you could save much more money if you use block walls instead.
• Reliability: When you use cast-in-place concrete, it could lose some of its tensile strength during the curing process. Concrete blocks are entirely cured, giving you the durability you need for your project. The weather may affect the integrity of a poured concrete wall, but a block wall contains materials that professionals have manufactured in a factory.
• Capability for large or heavy buildings: Concrete blocks can also often hold more weight than CIP concrete. If you have to build a dense, massive structure, concrete blocks can maintain the integrity of your project.
• Versatile design: Concrete blocks are available in a variety of colors to complement the landscape or structure of the project. You can install concrete blocks that look like natural stone to enhance your commercial project’s aesthetic. They also come in various sizes and shapes to fit your application and form a coherent structure.

Contact Nitterhouse Masonry for Block Walls

At Nitterhouse Masonry, we offer a wide variety of concrete block walls for your application, so you can find the units in the colors and shapes that you need from our collection of masonry products. Browse through our inventory of retaining and load-bearing wall materials, including our eco-friendly ecology block or our recycled concrete CMU. For more information about our masonry products, fill out an online form or call 717-267-4500.