Residential and commercial construction work primarily uses hollow-core blocks or concrete masonry units along with a mix of gravel, aggregate, and Portland cement.
Sometimes fly ash bricks or bricks made from industrial waste materials are also used.
Usually, block walls consist of the same elements. However, the application of the components can change depending on the process of laying concrete blocks.
Concrete block walls are built on a durable foundation of poured concrete mix. The size and depth of the foundation may vary depending on the wall’s size and weight.
Usually, freestanding walls require a foundation that is double the width of the wall and goes one foot deep into the ground below the frost line.
The shape and size of the wall should be as per the intended application. Different types of concrete blocks are available in the market for erecting walls. Contractors select blocks depending on the size, shape, and load-bearing capacity of a wall.
The blocks are laid in rows and joined with S-type or N-type mortar. To achieve maximum strength, concrete walls use vertical offset joints.
Freestanding block walls experience extreme stress that results in cracks in the joints. Therefore, vertical and horizontal reinforcements are necessary to prevent significant damage to the walls. Steel rebar is embedded inside the wet concrete for vertical reinforcement when it is poured into blocks.
For horizontal mounting, metal reinforcement strips are laid inside the mortar after every 3 or 4 blocks.
Tools Necessary For Building A Concrete Wall
- Mason’s string
- Excavation tools
- Line level
- Foundation forms
- Concrete blocks
- Plumb Bob
- Work gloves
- Carpenter’s level
- Mason’s trowel
- Masonry hoe
- Masonry hammer
- Masonry chisel
- Jointing tool
- Missionaries saw
A properly erected block wall adds both aesthetic and functionality to a landscape. But building them can be a difficult task without the proper knowledge. You need to take accurate measurements before putting up a block wall.
Besides, preparing the blocks and striking the joints are also essential for constructing a durable wall—the following section of this article lists four critical tips on how to lay concrete blocks.
- Preparing A Solid Footing
A firm footing is necessary for constructing a proper block wall. The ideal width of the footing should be twice the width of the block or more. The level of the wall footing should always be below the finishing line.
The builder may require special permission for constructing a block wall as per the regulations of the local body.
- Begin From The Corners
The construction of block walls starts from the corners and then makes its way to the inside. Corners of a block wall are referred to as leads. Performing a dry run of the layout is always beneficial before applying the mortar on the blocks.
It also helps in estimating that there is a sufficient number of blocks for finishing a particular task. Check the consistency of the mortar before laying the blocks over the foundation. Always dampen the footing before laying the blocks as it provides better adhesion.
- Buttering The Blocks
Buttering multiple blocks simultaneously is much easier than buttering individual blocks. Press down around the edges of a block with a trowel to prevent the mortar from coming off. Always allow the mortar to set a bit before scraping off the surface.
If you remove the mortar too soon after application, it can smear.
- Taking Proper Measurements
Continuously check for the level, square, and plan throughout the building process. This helps in fixing mistakes without much effort or significant adjustments. Check the consistency of the mortar periodically.
Hardening of the mortar indicates that it’s time to strike on the joint.
Strike the joints of the block after the mortar sets appropriately. A joining tool helps compress and smooth joints. It also removes excess water and gives the surface a cleaner finish. Always start with the horizontal joints and then gradually move over to the vertical ones.
Steps To Creating A Block Wall
The first step to creating a block wall involves laying out the foundation with masonry string and stakes.
Excavation is quite labor-intensive work and depends on the size of the foundation and the final structure. In addition, a builder must have legal clearances before starting excavation for erecting a wall.
Pouring The Foundation
A concrete foundation serves as a support structure to lay a concrete block. The foundation is prepared by pouring concrete inside a hollow form placed inside the excavation trench. Some builders pour the concrete mix directly inside the trench to make the foundation.
Line The First Course Of Block
After the foundation has cured completely, builders create an outline with wall blocks on top of the foundation. The process starts by applying a 1-inch thick layer of mortar on the foundation. Next, lay the first course of blocks on the mortar and tap them downwards.
Finally, use a level to check whether the blocks are aligned perfectly.
Cutting The Blocks
Sometimes, due to changes in the layout, you might be required to cut blocks for minor adjustments. Always use a power tool with a masonry blade for cutting the blocks.
Line Subsequent Block
After laying down the first course, begin laying the second course of blocks. This helps in securing the vertical joints. Keep a level or mason’s string to check the block course level repeatedly, as it is an essential step to lay concrete blocks.
Based on the project size and speed of work, you will be required to finish joints between blocks at regular intervals.
The top surface of wall blocks is capped with a layer of mortar, followed by metal reinforcement strips, and then covered with concrete cap blocks. This helps in giving the wall a smooth finish at the end.
Keeping the steps mentioned above in your mind on how to lay concrete blocks will be beneficial for maintaining the aesthetics and structural integrity of block walls.
Always remember to take repeated measurements and levels to avoid major adjustments after finishing.