Steel Shelf Angles and Masonry

The use of masonry veneer in building construction often requires steel shelf angles, which transfer the cladding load onto major elements of the concrete frame. Charleston Masonry also provides a space for movement within the masonry wall and between the structure and the cladding.

In one instance, a contractor bid the job, assuming there would be no sealant required under the shelf angle, and filled it with mortar. This allowed water to enter the wall, which led to damage.


Masonry is a durable, attractive, and highly customizable building material. A variety of surface treatments and coatings accentuate its beauty. In addition, it reflects light and shadows, presenting a color palette unique to each structure. It can also be augmented with electric lighting to enhance its colors and textures further. Many new technological advances have been made in masonry construction and materials. These include the use of slenderer units, improved strength parameters, and methods for reducing shrinkage cracking.

The most common causes of distress in brick masonry walls are corrosion and failure of embedded steel elements, including lintels, reinforcement, anchors, and ties. These failures often result in bending, bowing, or lateral displacement of the masonry wall system. This damage is usually caused by water penetration into the wall, causing steel lintels and other structural elements to corrode.

Other causes of distress in masonry walls are the failure of expansion joints or inadequate anchorage of the brick veneer to the backup system. When expansion joints are narrow or spaced too far apart, there needs to be more accommodation for masonry expansion. This can lead to brick movement and the formation of long vertical cracks in the facade. Inadequate anchorage can also cause lateral displacement of the veneer.

Another common cause of distress is the failure to install a lintel at door or window openings. This can cause a significant reduction in the building’s energy efficiency and may lead to problems with air sealing, moisture, or condensation. An engineer should size lintels to meet the steel design code. They should be stiff to minimize masonry cracks.

Efflorescence, which is white salty streaks visible on the surface of a masonry wall, is a common symptom of poor water management in masonry walls. It is the result of the leaching of water-soluble salts from the mortar. The best way to prevent this problem is to drain the walls and seal all exterior openings properly.

Lintels and shelf angles are important components of a masonry wall assembly. However, they need to be well-documented in the building physics literature. Sometimes, they create linear thermal bridges that reduce a wall’s R-value by 50% or more. Moreover, they can hinder energy code compliance for masonry veneer buildings.

Masonry walls are attractive, durable, and easy to repair. They can also be built with various colors and textures to suit any building design. They are also more insulated than wood frame walls, providing an R-value of about R-1 per inch. They also require fewer framing members, which means less maintenance over time. A brick wall also lasts longer than a wooden or metal framed wall, making it more cost-effective in the long run.

While masonry is an attractive construction material, it requires special detailing for movement control, moisture management, and thermal performance. One example is shelf angles, which transfer the load of a brick veneer to major elements of a concrete or steel frame and provide space for masonry and definite structural movements. When poorly designed and detailed, these supports can cause serious problems in a building’s structure and may not comply with building codes.

The design of shelf angles and lintels is a crucial aspect of masonry veneer construction. Engineers must consider the load and adequacy of the foundation, the size and location of windows and doors, the type of masonry anchorage, and the amount of movement expected in the cladding system. To reduce the risk of movement damage, the engineer should ensure that the lintels are designed to support a minimum of two-thirds of the maximum brick thickness, and that they are positioned at least 10 feet (8 m) from the foundation’s edge.

In addition to providing structural support, a lintel should have sufficient bearing capacity to resist lateral loads from wind and seismic pressures. This is especially important in high-rise buildings, where the lateral forces on the lintel can be considerable. In addition, the lintel should be anchored to the concrete or masonry backup system and not to the brick veneer.

Another key component of a good brick masonry support system is a flashing system and waterproofing. At all transitions between the brick veneer and the underlying backup, such as at shelf angles, lintels, and the base of the wall, flashing flexible, impermeable material is used to collect water and drain it away from the backing wall. To protect the brick masonry from moisture damage, flashings should be safeguarded by counter-flashings, which are attached to or directly laid into the backup. Drip edges, or downward bends in rigid flashings, encourage water to form droplets that fall away from the wall rather than flowing back up underneath the flashing and into the masonry.

Brick masonry is usually non-loadbearing, and the structure of the building must support its weight. It is commonly cladded with a single wythe of brick or other masonry, a veneer, that extends across wide openings. Shelf angles are typically installed to support this type of cladding. These are attached to the foundation or major elements of the building frame. To reduce thermal bridging, Armatherm FRR structural thermal break material can be placed behind the shelf angle to significantly lower the linear transmittance of heat from the foundation through the masonry veneer.

To install brick veneer, construct a rounded frame for the wall section using lumber and plywood. The frame is shaped to the exact curvature or radius of the wall section and must be supported from below. This will prevent the brick from collapsing under its weight. The frame must be placed before the mortar is applied, and a layer of masonry pointing mortar should be installed over it to prevent water intrusion into the framing members.

Before you start laying your first course of brick veneer, make sure that the base row is fastened to an angle iron that is attached to the foundation. Snap a chalk line along the foundation to ensure that the bricks will be straight, and cut the angle iron to length before installing it on the foundation with lag screws. You must also mark the foundation for a 3-inch-deep row of holes to drill and place lag shields around each hole.

Once you have laid your first course of brick, you must apply the second course over it. It would be best to use a lipped brick with one short leg and one long leg to alternate the positions of these pieces in each row. This will help ensure that the joints are evenly spaced and prevent sagging of the brick face over time.

You should also make sure that you fill all of the head joints in the brick veneer. This will prevent moisture from getting into the cavity, which can lead to mold and mildew. Moreover, it will also prevent the deterioration of the underlying sheathing. If the moisture penetrates the sheathing, it can cause serious problems for the entire wall assembly. To ensure proper brick veneer installation, you should hire a contractor who has completed advanced masonry training programs.

Many buildings we use and work in are constructed from masonry materials, including bricks. This type of construction is extremely durable, but it can wear down over time. This can cause serious damage and costly repairs if addressed slowly. This is why it is important to understand the warning signs of masonry problems and to take steps to prevent them.

One of the most common masonry issues is efflorescence, which results from soluble salts rising through concrete and coming out of the outer pores of the brick facade. This can look like a white stain and is usually caused by conditions of heightened moisture, such as rain, dew, and condensation. If it isn’t removed in time, it can develop into calcium carbonate, which can only be broken down by toxic and dangerous chemicals.

Another common masonry issue is cracking. These cracks are often the result of structural movement. Still, they can also be caused by thermal shock, poor foundation design, or subgrade soil conditions. It is important to repair these cracks promptly as they can weaken the structure and lead to further problems.

It is also essential to inspect the steel lintels and shelf angles regularly. This is particularly important if the building is in a high wind zone or where there is frequent rainfall. Regular inspections can identify deterioration and potential problems before they become more serious. The inspection should include:

  • A probe of the steel plate.
  • An assessment of the lifespan and usage of the lintels or angle.
  • Recommendations for critical maintenance and repair.

A good masonry restoration contractor can help you with any masonry issues that may arise in your home or business. These can range from simple tuckpointing to more complex projects, such as brick replacement or rebuilding an entire wall. Repairing masonry is much less expensive and stressful than fixing it later.

If you’re noticing bricks disintegrating, this is a sign that the mortar that holds them together has deteriorated. This can allow water into the masonry, leading to structural damage and mold. It’s also important to watch for bricks that are bulging. These can signify a frost boil, where moisture seeps into the back of your brick masonry. This is often exacerbated by freeze-thaw cycles, which can cause the expansion of trapped moisture within the masonry walls.