Mortaring cement blocks is a crucial step in constructing sturdy and durable walls. Whether you’re a seasoned builder or embarking on a DIY project, mastering the art of mortaring cement blocks is essential. This comprehensive guide will walk you through the entire process, providing invaluable tips and insights to ensure a successful outcome.
Before diving into the practical aspects, it’s worth understanding the significance of mortar in cement block construction. Mortar acts as an adhesive, binding the blocks together and creating a solid structure. It also fills the gaps between the blocks, preventing water penetration and structural weaknesses. Choosing the right type of mortar for your project is crucial, and we’ll explore the various options in detail later in this article. Additionally, ensuring proper mixing and application techniques will guarantee a strong and long-lasting bond.
Preparing the blocks for mortaring involves cleaning and wetting them. This step enhances the adhesion between the mortar and the blocks, resulting in a more secure bond. The mortar is then applied to the bed joints, which are the horizontal spaces between the blocks. Using a trowel, spread the mortar evenly across the bed joint, ensuring there are no voids or gaps. Once the mortar is in place, the blocks are set in position and tapped gently with a rubber mallet to ensure a tight fit. The excess mortar is removed, and the process is repeated for each subsequent course of blocks.
Bonding the Blocks
4. Mortar
The mortar used for laying cement blocks is typically a mix of cement, sand, and water. The proportions of these ingredients will vary depending on the specific application, but a general rule of thumb is to use one part cement to three parts sand to one part water.
| Mortar Mix | Applications |
|---|---|
| 1 part cement to 2 parts sand to 1 part water | General purpose mortar, suitable for most applications |
| 1 part cement to 3 parts sand to 1 part water | Thinset mortar, used for setting tiles or other thin materials |
| 1 part cement to 4 parts sand to 1 part water | Drystack mortar, used for creating decorative or non-load-bearing walls |
It is important to mix the mortar thoroughly until it reaches a uniform consistency. The mortar should be wet enough to spread easily, but not so wet that it will drip off the block. If the mortar is too dry, it will be difficult to work with and may not adhere properly to the blocks. If the mortar is too wet, it will be weak and may not provide adequate support for the blocks.
Once the mortar is mixed, it should be applied to the blocks in a thin, even layer. The mortar should be spread using a trowel or a mortar gun. The thickness of the mortar layer will vary depending on the application, but a general rule of thumb is to use a layer that is about 1/4 inch thick.
Aligning the Joints
5. Aligning the Blocks
Once the first course is complete, align the second course of blocks by placing them over the first course, ensuring each block is parallel and aligned with the previous one. Use a string line to maintain the straightness of the wall, and check the alignment regularly with a level.
Laying the Blocks with Mortar
* Apply a thin layer of mortar (about 1/4- to 1/2-inch thick) to the edges of the block that will be in contact with the adjacent block.
* Carefully align the block and press it into place to ensure full contact with the mortar.
* Gently tap the block with a rubber mallet to adjust its position as needed.
* Use a trowel or mortar bag to fill in any gaps between the blocks and smooth the surface.
* Leave a consistent joint width throughout the wall. The typical joint width is 3/8 to 1/2 inch. Use a jointing tool to create a clean and uniform joint.
* Repeat these steps for subsequent courses until the wall reaches the desired height.
| Joint Width | Description |
|---|---|
| 1/8 to 1/4 inch | Narrow joints suitable for thin veneers or architectural applications |
| 3/8 to 1/2 inch | Standard joint width suitable for most building applications |
| 5/8 to 1 inch | Wider joints typically used for decorative finishes or in areas requiring drainage |
Filling the Joints
Once you have placed the first course of blocks and aligned them, you can begin filling the joints with mortar. To do this, use a pointing trowel or a mortar bag. If you are using a pointing trowel, scoop up a small amount of mortar and apply it to the joint. Use the trowel to spread the mortar evenly and fill the joint completely. If you are using a mortar bag, fill the bag with mortar and then squeeze the bag to apply the mortar to the joint. Use your finger to smooth out the mortar and ensure that it is completely filled.
When filling the joints, be sure to press the mortar firmly into place. This will help to create a strong bond between the blocks and prevent the mortar from cracking or crumbling. You should also be sure to remove any excess mortar from the surface of the blocks. This will help to prevent the mortar from staining the blocks or causing efflorescence.
Tips for Filling the Joints
- Use a pointing trowel or a mortar bag to apply the mortar.
- Press the mortar firmly into place.
- Remove any excess mortar from the surface of the blocks.
- Use a damp sponge to clean up any excess mortar.
- Allow the mortar to cure for at least 24 hours before applying any load to the wall.
Common Mistakes to Avoid When Filling the Joints
- Do not use too much mortar.
- Do not press the mortar too firmly into place.
- Do not remove too much excess mortar from the surface of the blocks.
- Do not allow the mortar to cure too quickly.
- Do not apply any load to the wall before the mortar has cured for at least 24 hours.
| Mistake | Consequences |
|---|---|
| Using too much mortar | Can cause the mortar to crack or crumble |
| Pressing the mortar too firmly into place | Can cause the blocks to crack |
| Removing too much excess mortar from the surface of the blocks | Can cause the mortar to dry out too quickly and crack |
| Allowing the mortar to cure too quickly | Can cause the mortar to be weak and crumble |
| Applying any load to the wall before the mortar has cured for at least 24 hours | Can cause the wall to collapse |
Finishing Touches
Once you have laid all the cement blocks and the mortar has dried, you can add the finishing touches to your project.
9. Installing Coping Caps
Coping caps are concrete or stone pieces that are placed on top of the cement blocks to protect them from rain and other elements. They also add a decorative touch to your project.
To install coping caps, you will need to:
- Measure the length of the top of the cement blocks.
- Cut the coping caps to the correct length.
- Apply a bead of mortar to the top of the cement blocks.
- Place the coping caps on the mortar.
- Use a level to make sure the coping caps are level.
- Allow the mortar to dry completely.
**Tips:**
- Use a wet saw to cut the coping caps. This will help to prevent them from chipping or breaking.
- Apply the mortar in a thin, even bead. This will help to ensure that the coping caps are secure.
- Allow the mortar to dry completely before using the cement block wall. This will help to prevent the coping caps from moving or becoming loose.
| Coping Cap Material | Advantages | Disadvantages |
|---|---|---|
| Concrete | Durable, affordable, easy to install | Heavy, can crack or chip |
| Stone | Beautiful, durable, long-lasting | Expensive, difficult to install |
| Brick | Versatile, easy to install, affordable | Not as durable as concrete or stone |
How To Mortar Cement Blocks
Mortaring cement blocks is a relatively simple process that can be completed in a few hours. However, it is important to follow the steps carefully to ensure that the blocks are properly bonded together and that the mortar is strong and durable.
To begin, you will need to gather the following materials:
- Cement blocks
- Mortar
- Trowel
- Level
- String line
- Measuring tape
Once you have gathered your materials, you can begin the process of mortaring the cement blocks.
- Start by laying out the first course of blocks on a level surface. Use a string line to ensure that the blocks are aligned properly.
- Spread a layer of mortar on the top of the first course of blocks. The mortar should be about 1/2 inch thick.
- Place the second course of blocks on top of the mortar. Use a level to ensure that the blocks are level.
- Continue adding courses of blocks until the wall reaches the desired height.
- Once the wall is complete, allow the mortar to cure for at least 24 hours before applying any weight to it.
People Also Ask About How To Mortar Cement Blocks
How do you lay cement blocks with mortar?
To lay cement blocks with mortar, you will need to follow the steps outlined in the “How To Mortar Cement Blocks” section above.
What is the best mortar for cement blocks?
The best mortar for cement blocks is a type N mortar. This type of mortar is strong and durable, and it is specifically designed for use with cement blocks.
How thick should the mortar be when laying cement blocks?
The mortar should be about 1/2 inch thick when laying cement blocks.
