A-F
AGGREGATE
Granular material consisting of normal weight or lightweight particles used with a cementing medium to form concrete masonry, mortar or grout.
ANCHORS
There are two primary types of anchors in masonry systems: wall anchors and stone anchors. Wall anchors are typically used to tie wythes (layers) of masonry together; in modern masonry, that is typically an anchor that ties the brick or stone veneer to the block (CMU) backup wall. Stone anchors hold stone in the wall system and prevent its movement.
Most modern anchors are made of galvanized steel or stainless steel that are resistant to rusting. However, anchor failure – usually caused by rusting – is common in older buildings. Rusting anchors often cause cracking and spalling in masonry as the rust expands. Fully failed anchors can cause movement in the masonry or bulging of the outer wythe of masonry.
ANCHOR BOLTS
Threaded bolt placed in grouted masonry unit opening. Used to fasten wood will, beam or other structural support to wall top.
CAULK (CAULKING)
Sealing material, the process of sealing cracks around doors, windows and other cracks with a caulking gun. See Joint Sealant
CMU
Concrete Masonry Units (also known as blocks or cinder blocks) are manufactured from cast concrete. Standard blocks have flat faces and, when used in exterior walls, are often used as the structural component of a composite wall with a brick or stone veneer attached to the exterior side. However, in commercial and industrial buildings, CMU are often used without a veneer wythe – in this case, CMU with decorative faces, such as split-face and fluted, are often used for aesthetics.
CMU are a durable building product and can last for extended lengths of time. However, they are not immune from failure from weathering, excessive forces, or movement. Cracked CMU should generally be replaced to maintain integrity of the wall and prevent damaging surrounding wall components. Weathered masonry that is not cracked or excessively worn can often be cleaned and treated with a water-repellent.
Coating
Coatings for masonry resist water penetration and can improve the aesthetics of the masonry to which they are applied. A fundamental feature of a quality coating is vapor permeability which allows moisture within the masonry to escape to prevent damaging the coating or the masonry. Coatings can be a modified cementitious material or an elastomeric membrane.
Coatings are often a valid option to hide surface defects in stone or masonry or to minimize moisture penetration where hairline cracks are present and full replacement is not feasible. However, coatings do have a finite lifetime and do need to be replaced after a period of years.
Concrete Masonry Joints
Concrete masonry shrinks over time – including CMUs. To reduce the occurrence of shrinkage-related cracking, vertical control joints are placed in CMU walls. These joints are sealed with a joint sealant that is flexible and will accommodate movement yet remain watertight.
As with all joint sealant applications, they are maintenance items with a finite life and they should be monitored for cracking, hardening, or separation. If these signs of failure are noted, the sealant should be replaced.
Copings
Copings (also known as wall caps) are used to cover the top of a wall to prevent water entry. On masonry walls, copings are often stone, clay tile, or metal.
Since copings prevent water from entering directly into the wall system, it is vital that they are maintained in a watertight condition. Damaged coping should be a priority repair. Attention should also be paid to the joints between coping stones; any cracking, hardening, or separation in the joint sealant is an indication for replacement.
Coursing
A continuous horizontal row of any masonry unit – such as brick, CMU, or stone.
Expansion Joint
Clay masonry, such as brick, expands with moisture absorption and temperature. To accommodate this expansion, joints are placed in the wall which allows this movement to occur without damaging the brick. These joints are sealed with a joint sealant that is flexible and will accommodate movement yet remain watertight.
As with all joint sealant applications, they are maintenance items with a finite life and they should be monitored for cracking, hardening, or separation. If these signs of failure are noted, the sealant should be replaced.
Flashing
Flashings are typically placed within walls to prevent water from entering the interior of the wall and directing it to the exterior. Flashings are typically a composite of rubber and plastic or thin sheet metal. They can commonly be found at interruptions in wall cavities, such as at wall openings, where they direct moisture in the cavity to the exterior of the wall through weeps. They are also often found, as a redundant water barrier, under horizontal components that are exposed to precipitation such as copings and window sills.
Flush Joint
Any joint finished flush with the surface.
G-P
Grout
1. Mortar containing a considerable amount of water so that it has the consistency of a viscous liquid, permitting it to be poured or pumped into joints, spaces and cracks within masonry walls and floors, between pieces of ceramic clay, slate and floor tile, and into the joints between performed roof deck units.
2. In foundation work, mixtures of cement, cement, sand, clay or chemicals; used to fill voids in granular soils, usually by a process of successive injection through drilled holes.
Infills
An infill refers to installing masonry in an existing opening that is no longer needed. Infills are typically constructed of the same material as the surrounding masonry. Where aesthetics are not a concern, the infill masonry can be built up to the jambs on the existing opening. This is less costly, but the infilled area is clearly visible as the coursing is broken at the jambs. Alternatively, the infill can be toothed into the surrounding masonry such that the brick or CMU creates continuous coursing. A quality infill usually involves the removal of the unneeded lintel and a close match of the infill masonry to the surrounding masonry.
Isolation Joints
1. A joint where two successive placements of concrete meet.
2. A separation provided in a building which allows its component parts to move with respect to each other. The cause of such movement may be thermal, seismic or wind loading.
Joint sealants
Joint sealants (also known as caulking) as used for weather-sealing components of masonry systems. They seal gaps or joints to prevent air and moisture entry. As these sealants are commonly used in joints that are moving (from changes in temperature, moisture, loads, settling, etc.), a key feature is that they can readily extend and compress without separating from the substrates to which they are applied.
Joint sealants are maintenance items with a finite life and they should be monitored for cracking, hardening, or separation. If these signs of failure are noted, the sealant should be replaced. When replaced, it is important that the existing sealant be completely removed from the joints, the substrates are solvent cleaned, and that backer rod or bond breaker tape is used to create the proper joint dimensions and prevent three-sided adhesion that will result in premature failure.
Lintels
A lintel is a structural horizontal element that spans over an opening in masonry to support the masonry over the opening. Lintels are often steel, stone, or concrete.
Rusting steel lintels are a common source of failure in masonry. Rust can expand up to seven times its original thickness and it can do so with a force as high as 9,000 psi. It is not uncommon to see rusting lintels on top floor windows cause entire parapets to tip significantly. Thus, rusting lintels should not be underestimated and should be refurbished or replaced. Replacement should be with galvanized steel lintels and should include the replacement of flashing and weeps, as well.
Masonry
The art of shaping, arranging, and uniting stone, brick, building blocks, etc., to form walls and other parts of a building.
Mortar joints
The exposed joints of mortar in masonry.
Mullions
A vertical element that forms a division between units of a window, door, or screen, or is used decoratively. When dividing adjacent window units, its primary purpose is to provide structural support to an arch or lintel above the window opening.
Needleglaze
Application of a small bead of sealant at the perimeter of window glass. Needleglazing is performed to seal windows that have failing gaskets.
Parapet detail
A barrier which is an extension of the wall at the edge of a roof, terrace, balcony, walkway or other structure.
R-Z
Reinforcing
Masonry reinforcement typically refers to the vertical rebar and horizontal truss or ladder wire in CMU wall construction. However, it can also refer to rebar embedded in grout between two brick wythes.
Reinforced Brick Masonry
Grouted brick masonry in which reinforcement is provided in the horizontal joints and in grouted vertical joints between withes.
Remedial Anchors
Systems that combine the required strength with flexibility, durability and great holding power in all commonly used building materials.
Sealant
Silicone, polyurethane or polysulphate based chemicals with elastomeric (elastic) characteristics used at various conditions in stone joints.
Sill
A horizontal member that bears the upright portion of a frame.
Toothing
Toothing is a technique to create a continuous coursing of brick or CMU when new masonry is added contiguous to existing masonry such as when an opening is being infilled or when a wall is being extended. This is done by removing one brick from every other course on the existing masonry such that new full bricks can be laid in a continuous course.
Tuck pointing
Tuckpointing, or more properly repointing, is the process of removing and replacing cracked, deteriorated, damaged or missing mortar in brick, block, stone and other masonry units. Mortar has a long life span, but eventually (and often with the help of stresses and/or moisture) it can become damaged.
The quality of a repointing job has a large impact on the longevity of the repair and on the potential for damaging the surround masonry. Mortar must be removed carefully to prevent damaging the brick, stone, or block around it, yet it must be removed to a sufficient depth. Replacement should be done in well compacted layers and the final layer should be tooled to match the existing. However, one of the most important aspects is the composition of the mortar. Especially in historic buildings, the mortar should match in color, sand characteristics, and hardness/permeability. Older mortars used lime, rather than Portland cement, as the primary binder; they were softer and more permeable. Repointing this older mortar with a modern mortar – which is harder – creates a very real risk of causing damage to the masonry units (e.g. brick) as the hard joints do not “give” to relieve stresses and, therefore, the stresses are transmitted to the softer masonry units
Weathered Joint, Weather-Struck Joint
A horizontal masonry joint in which the mortar is sloped outward from the upper edge of the lower brick, so as to shed water readily; formed by pressing the mortar inward at the upper edge of the joint.