Building a brick wall directly on soil requires careful preparation to ensure stability and prevent the wall from sinking or cracking. Here's a step-by-step guide:
Important Note: Building a brick wall directly on soil without a proper foundation can be risky, especially in areas with expansive soil or significant frost heave. Local building codes may prohibit this and require a concrete footing. This guide provides basic steps but doesn't substitute for professional advice. Always consult with a structural engineer or experienced mason before starting any construction project.
Steps for Building a Brick Wall on Soil (with caveats)
1. Preparation is Key
This is the most crucial step. Building directly on soil is generally not recommended unless it's incredibly well-draining, stable soil and the wall is short and non-load-bearing (e.g., a low garden wall). Assume the soil needs improvement.
- Clear the Area: Remove all vegetation, debris, and topsoil from the intended wall location. Dig down at least 6-12 inches (or more, depending on local frost depth and soil conditions).
- Compact the Soil: Use a plate compactor to thoroughly compact the exposed soil. This creates a denser base and minimizes settling.
- Gravel Base (Essential): Add a layer of compacted gravel (4-6 inches thick) to improve drainage and provide a stable footing. Compact the gravel thoroughly. Crushed stone is preferable to pea gravel.
- Landscape Fabric (Optional but Recommended): Lay down landscape fabric between the soil and the gravel base. This helps prevent soil from mixing with the gravel over time, maintaining drainage.
2. Laying the First Course (Most Critical)
The first course of bricks is the foundation of the entire wall.
- String Line: Use a string line to ensure a perfectly straight line for the first course. Drive stakes into the ground at either end of where the wall will be and tie the string tightly between them.
- Mortar Bed: Prepare a mortar mix according to the manufacturer's instructions. Only mix enough mortar that you can use within a reasonable time frame (before it hardens). A good mix is typically 3 parts sand, 1 part cement, and 1/2 part lime.
- Spread Mortar: Spread a layer of mortar (approximately 1 inch thick) along the gravel base, using a trowel.
- Lay the Bricks: Carefully lay the first course of bricks on the mortar bed, ensuring they are level and aligned with the string line. Use a level to check each brick. Maintain consistent mortar joints (typically 3/8 inch).
- Corner Bricks First: If building a longer wall, focus on laying corner bricks first. These act as guides for the rest of the course. Use a mason's level to ensure the corners are plumb (perfectly vertical).
3. Building Subsequent Courses
- Stagger the Joints: Stagger the brick joints on each subsequent course to create a stronger wall. This is typically done by starting each course with a half brick (header).
- Apply Mortar: Apply mortar to the top of the previous course and to the end of each brick before laying it.
- Press and Align: Press each brick firmly into the mortar, ensuring it's level and aligned with the previous course. Use a level and the string line as guides.
- Tool the Joints: After the mortar has partially set (but is still pliable), use a jointer to create a smooth, consistent finish to the mortar joints. This improves the appearance and weather resistance of the wall.
4. Ongoing Checks and Drying
- Regularly Check for Plumb: Use a mason's level to ensure the wall remains plumb as you build. Make adjustments as needed.
- Remove Excess Mortar: Remove excess mortar from the face of the bricks with a trowel as you go.
- Curing Time: Allow the mortar to cure properly. Keep the wall damp for several days by misting it with water, especially in hot or dry weather. This helps the mortar to harden properly.
5. Drainage Considerations
Even with a gravel base, water can still be a problem. Consider adding a drainage pipe behind the wall at the base to carry away excess water. This is highly recommended, especially in areas with heavy rainfall or poor drainage.
Disclaimer: This guide is for informational purposes only and does not constitute professional advice. Building codes and local conditions vary. Always consult with qualified professionals before undertaking any construction project. Building directly on soil carries risks of settling and instability.
