7 Best Line Blocks For Bricklaying Pros Trust

Achieving a perfectly level brick course relies entirely on the tension and accuracy of the mason’s line. Without reliable line blocks, even the most skilled bricklayer will struggle to maintain consistency across a long wall run. These simple tools act as the anchors for the entire project, bridging the gap between a chaotic stack of bricks and a professional, plumb facade. Selecting the right block is a foundational decision that impacts the speed and quality of every masonry job.

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Marshalltown LBL839: The Pro’s Go-To Choice

The Marshalltown LBL839 is widely recognized as the industry standard for a reason. Its high-impact plastic construction provides enough rigidity to maintain constant tension without snapping under the pressure of a tightly pulled line.

Weight distribution is where this block excels. It sits flush against the brick face, ensuring the line remains perfectly aligned with the edge of the unit. For contractors working on long, multi-story commercial projects, this reliability prevents the line from sagging or “bowing” in the middle of a lead.

The bottom line is simple: if the project requires high-volume output and consistent accuracy, the LBL839 is the safest investment. It bridges the gap between affordable accessibility and professional-grade performance.

Bon Tool Pro Plus: Built for Heavy-Duty Use

When moving into heavy-duty masonry work, such as laying block or thick-bed brick, standard plastic blocks can sometimes deform. The Bon Tool Pro Plus addresses this by utilizing reinforced material that resists the constant scraping and impacts typical of a busy job site.

This block is designed with a deep recess for the line, which helps keep the twine from jumping out during a shift. When working on large-scale masonry walls where the line might be up for hours at a time, this stability is crucial.

Contractors dealing with abrasive materials or rough, oversized brick should favor this model. It is built to withstand the abuse of a professional environment where tools are often tossed into a truck bed at the end of the day.

Kraft Tool PL405: Best for Perfect Corners

Precise corners define the quality of the entire wall. The Kraft Tool PL405 is engineered with geometry that specifically aids in maintaining clean, sharp corner lines without causing the line to slip or rub against the brick edge.

Because corners often act as the pivot points for the wall, any movement in the line block will be magnified across the entire course. The Kraft design features a secure slot that locks the mason’s line in place, ensuring that even if the line is accidentally nudged, the tension remains consistent.

For those focusing on intricate brick patterns or tight, exposed corner work, the precision of the PL405 is unmatched. It is the tool of choice for detail-oriented masons who view every corner as a testament to their craft.

W. Rose Wood Blocks: The Traditionalist Pick

Modern plastics have their place, but many veterans still prefer the feel and grip of W. Rose wood blocks. Wood provides a natural friction that holds a mason’s line in place better than some slicker plastics, especially when working in cold or damp conditions.

The texture of the wood is gentle on the brick surface. Unlike hard plastic blocks that might chip the arrises of a decorative brick if bumped, wood has a natural “give” that minimizes damage to the finished face.

The tradeoff is maintenance; these blocks require a bit more care and can deteriorate if left submerged in mortar or water for too long. However, for the mason who prefers a tactile, traditional experience, these remain the gold standard for finish work.

GOLDBLATT Rubber Blocks: Grip Without Damage

Rubber-based line blocks offer a unique advantage in surface protection. The Goldblatt rubber blocks are engineered to provide maximum surface friction, which allows them to grip the face of the brick without sliding, even on smooth, glazed, or high-end architectural bricks.

These are particularly useful when working on high-end residential projects where scratch-free surfaces are non-negotiable. If you are laying expensive face brick that would show a scratch from a standard plastic block, these rubber alternatives are a necessity.

The material is naturally resilient and will not crack or chip under heavy use. It is a smart choice for any site where surface protection is just as important as structural alignment.

IRWIN STRAIT-LINE: A Reliable Budget Option

For the DIYer or the contractor who needs a reliable backup, the Irwin Strait-Line represents the intersection of accessibility and utility. These blocks are lightweight and easy to maneuver, making them ideal for quick repairs or smaller residential projects.

While they may not have the heavy-duty reinforcement of a commercial-grade tool, they perform exactly as advertised for standard brickwork. The design is straightforward, intuitive, and effective for those who do not require specialized heavy-duty features.

Do not mistake affordability for a lack of quality. These tools are more than capable of keeping a line tight for a standard garden wall or porch repair.

Footprint Wood & Steel: Classic UK Durability

The Footprint line represents the classic European approach to tool design: heavy-duty materials meant to last a generation. Often featuring steel components, these blocks provide a level of stability and weight that prevents them from shifting even in high-wind conditions on an exposed scaffold.

These are the workhorses of the trade. If the project involves long, high-exposure walls where the line must remain dead-steady despite external forces, this is the tool to use.

The weight acts as a natural anchor, keeping the line taut and secure. While they are heavier to carry, the trade-off in stability is significant when working in challenging exterior environments.

Choosing the Right Mason’s Line for Your Blocks

• Braided vs. Twisted: Use braided mason’s line for better resistance to fraying and superior tension holding.
• Visibility: Choose high-visibility colors like neon yellow or pink; it is much easier to see the line against a grey mortar bed.
• Material: Nylon is standard, but specialized heat-resistant lines are available for projects requiring high-tension, long-span setups.
• The “Stretch” Factor: High-quality braided line has minimal stretch, which prevents the line from sagging after you have spent time leveling it.

How to Set Up a Line for a Perfect Brick Course

Setting up a line is more than just stretching a string between two points. Start by ensuring your corner leads are built plumb and level, as these are the anchors for your line blocks.

When placing the blocks, ensure they are flush with the top edge of the brick to account for the width of the mortar joint. If the line is set too low, the bricks will tilt outward; too high, and the course will be uneven.

Always check for line sag after you have tensioned the blocks. If the wall is long, place a “line twig” or a small support in the middle to prevent the weight of the string from bowing. A tight, straight line is the only way to guarantee a professional, level finish across an entire wall.

Line Block Materials: Wood vs. Plastic vs. Rubber

• Plastic: The most common choice; lightweight, durable, and highly affordable. Best for general-purpose masonry.
• Wood: Offers the best grip and is the most forgiving on delicate or high-end face brick. Requires more maintenance to keep from rotting.
• Rubber: The top choice for scratch-free, high-friction applications. Excellent for smooth surfaces where plastic might slide.
• Metal/Steel: Heavy-duty, high-stability options. Use these for large-scale outdoor projects where wind and scale make lighter blocks prone to movement.

Ultimately, the choice of a line block comes down to the scale of the wall and the sensitivity of the material. Whether you are leaning toward the proven reliability of a Marshalltown plastic block or the traditional feel of a W. Rose wood block, ensure your choice aligns with the specific needs of the job site. A well-set line is the difference between a wall that looks like it was laid by a novice and one that speaks to decades of professional experience. Take the time to get the tension right, and the brickwork will follow.