When laying the first course of bricks, the mason will usually not spread a full mortar bed. It allows the mason to check the modular dimensions of the foundation footing or slab and how the first course leads up to openings such as windows. Per code, structures utilizing brick veneer over 30 feet must operate shelf angles at every floor level. Inadequate design and construction of these elements can cause problems such as:
Pro Angle Masonry Charleston is a very stable, versatile, and durable material. It’s used for a wide range of applications and projects, and it comes in various shapes, sizes, and thicknesses. For instance, larger pieces are more common for structural projects because they can withstand more force and weight. They can also be welded or bolted together for additional stability and strength.
In traditional masonry buildings, brick, stone, or other cladding was installed over load-bearing walls, and openings such as doors and windows were small and spanned by steel lintels. With the invention of skeleton frame buildings, it is possible to construct larger spaces in masonry veneer that are non-load bearing. Still, the wall must be supported by a shelf angle so that expansion and contraction can occur.
Shelf angles are typically installed on every floor in a building to support the brick coursing above window and door lintels. However, this standard design detail interrupts the continuity of exterior insulation and increases operating (energy) costs. It’s important to eliminate these cold bridges wherever possible to minimize energy costs and improve the thermal performance of the structure.
To reduce upfront construction and maintenance costs, a simple method to minimize the need for shelf angles is to install a continuous metal drip edge flashing around the perimeter of all walls that require a shelf angle. The flashing will prevent rainwater from collecting in the gap and over the exposed front face of the steel angle.
In addition to preventing water intrusion, the continuous metal drip edge can provide better weather resistance by providing a solid surface that is not vulnerable to corrosion. In addition, it can help to prevent the rusting and failure of mortar joints at the lintel/flashing interface, which can lead to premature decay and oversight of the masonry veneer.
A standard sizing format for shelf angles consists of two leg measurements and a thickness measurement. These dimensions determine whether the curve is equal or unequal. Service Steel stocks both types and provides a sizing chart here. However, the project-specific sizing may differ from the standard format, so contacting the engineering team before bidding is important to ensure that the proper angle size is specified.
Corbels are a common feature of many different types of architectural design, whether they’re found on historical buildings that have been restored or newer properties where owners have chosen to implement traditional elements into their plans. They come in a wide range of styles, from the fluted designs popular with Georgian properties to the carved foliage of Victorian fixer-uppers or the sleek and simple brackets in contemporary properties.
Despite their appearance, they are also structural elements and can help to support features like shelves, arches, and other load-bearing structures. Corbels are normally triangular and designed to resist forces by distributing them along the surface of the network they’re supporting.
Aside from their structural benefits, wood corbels can also add a decorative touch to interior spaces. It is where they come into their own and are a great way to add a splash of style to a room without overdoing it or detracting from the overall look. The beauty of these decorative brackets is their versatility and the fact that they can support different home items, from kitchen utensil racks to bathroom towel shelves.
When choosing a corbel, it’s important to consider the rated load capacity, material, and design. If the corbel carries a significant amount of weight, a larger one will be required, and it’s often advisable to choose a wood type that matches the rest of the decor in the space.
Those looking to incorporate salvaged corbels into their decorating can often find some excellent options at flea markets, estate sales, and consignment shops. Alternatively, some enjoy restoring them to their original condition, and the weathered authenticity of older timber brackets can give a space a real feel of history and character. Just be sure to research the best practices for refinishing wood if you plan on doing this, as this is not something to be taken lightly. Suppose you’re planning to use them as a decorative element. In that case, however, their natural patina and weathered charm are often attractive features and can be a real focal point of a room.
Many brick restoration projects involve repairing or replacing damaged or defective relieving angles. It is important to understand the structural connection of these angles to the masonry system they support to prevent premature failure.
A relieving angle is a metal or concrete masonry element that transfers out-of-plane loads to the wall or backing. It is normally used with a cladding material such as brick, stone, or concrete masonry that adds significant weight to the supported system. This additional weight can cause stresses and movement of the building frame, and if the relieving angle is not designed to accommodate this movement, it may fail.
The design of the relieving angle depends on the cladding being installed, the loading conditions, and the size of the structure. The relieving arch may also interact with the tie rod system in the cavity walls to provide additional lateral stability.
Generally, relieving angles are placed between the brick veneer and the stud or concrete frame wall to prevent water infiltration into the wall cavity. It is accomplished by forming an obtuse or apex on one end of the angle to allow the hole to drain and by preventing water from accumulating under the bricks. The obtuse or apex may also help resist lateral forces in the cavity walls and reduce thermal bridging.
Relieving angles are typically fabricated from galvanized or stainless steel and are available in various shapes, sizes, and materials. The engineer on the project determines the size of the relief angle to provide adequate structural support for the load being transferred.
Inadequate design of the relieving angle and bad installation can result in spalling, cracking, and staining of the cladding; yielding and slipping of the relieving hooks; leakage of wind-driven rain and deterioration of the brick masonry and window frames; freeze-thaw damage and destructive cryptofluorescence; volume change of materials and structural members; increased heat transmission and occupant discomfort.
One of the most common deficiencies of relieving angles is that they must be properly detailed to accommodate brick expansion and shrinkage. It is recommended that a thru-wall flashing be installed at each relief angle to protect the structure from moisture intrusion, which can lead to corrosion of the metal and premature deterioration of the brick wall. The Brick Industry Association provides clear guidelines on properly detailing such flashings in the Brick Construction Technical Note TN 18A.
Lintels are used to support the brickwork over a masonry opening. They are typically installed at each floor level of a structure and are designed to help the brick veneer above that level for that story. Lintels are also useful in supporting wall sections that need extra load-bearing capacity. They are especially important in building a house because they provide stability and strength to the walls above.
There are several types of lintels available in the market. The most common ones include rolled steel lintels, concrete channel sections, and brick lintels. Steel lintels are typically made from rolled steel joists embedded in concrete. They are usually used in large openings with a significant load or where there isn’t enough room above to create a relieving arch.
Brick lintels are generally constructed with a left lengthwise space for inserting reinforcement. The area with support is then filled or embedded with rich cement mortar. When making brick lintels, it is advisable to use a special type of brick with frogs (end corners) that are thicker than regular bricks and help increase shear resistance.
Another popular kind of lintel is a reinforced concrete (RCC) lintel. This lintel is made using plain concrete, as steel bars are not used. It is ideal for heavy loads as it has a greater load-bearing capability than other lintels.
Lastly, there is the timber lintel beam. They are commonly used in hilly areas but have been replaced by several modern techniques. The disadvantages of using a timber lintel are that they are more expensive, less durable, and vulnerable to fire.
Ensuring a lintel is correctly positioned and installed in a structure is important. An engineer should size the lintel to meet the required strength requirements. It should also be properly placed to prevent masonry cracks. In addition, it is crucial to check that the lintel is not deflecting too much between supports. It can be determined by calculating the effective span of the lintel and comparing it to the height of the masonry above the opening.