Masonry and Your Home’s Construction. Masonry is the building of structures from individual units laid in and bound together by mortar, and the term also refers to the units themselves. The common materials of masonry construction are brick, stone (such as marble, granite, travertine and limestone), concrete block, glass block, and tile. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar, the workmanship, and the pattern the units are assembled in can strongly affect the durability of the overall masonry construction.
Masonry is commonly used for the walls of houses, but its popularity depends sometimes on the geographical area. Brick and concrete block are common types of masonry. They may be either load-bearing (structural) or used as a veneer. Blocks of cinder concrete (cinder blocks or breezeblocks), ordinary concrete (concrete blocks), or hollow tile are generically known as Concrete Masonry Units (CMUs). They usually are much larger than ordinary bricks and so are much faster to lay for a wall of a given size. Furthermore, cinder and concrete blocks typically have much lower water absorption rates than brick. They often are used as the structural core for veneered brick masonry, or are used alone for the walls of factories, garages and other industrial style buildings where such appearance is acceptable or desirable.
Polymer cement mortars (PCM) are the materials which are made by partially replacing the cement hydrate binders of conventional cement mortar with polymers. The polymeric admixtures include latexes or emulsions, redispersible polymer powders, water-soluble polymers, liquid resins and monomers. It has low permeability, and it reduces the incidence of drying shrinkage cracking, mainly designed for repairing concrete structures.
Most insulated buildings that utilize concrete block, brick, adobe, stone, veneers or some combination thereof feature interior insulation in the form of fiberglass batts between wooden wall studs or in the form of rigid insulation boards covered with plaster or drywall. In most climates this insulation is much more effective on the exterior of the wall, allowing the building interior to take advantage of the aforementioned thermal mass of the masonry. This technique does, however, require some sort of weather-resistant exterior surface over the insulation and, consequently, is generally more expensive.
Concrete block, when reinforced with concrete columns and tie beams, is a very common building material for the load-bearing walls of buildings, in what is termed “concrete block structure” (CBS) construction. American suburban houses typically employ a concrete foundation and slab with a concrete block wall on the perimeter. Large buildings typically use copious amounts of concrete block; for even larger buildings, concrete block supplements steel I-beams.
Masonry deterioration may happen by spalling, which is mechanical weathering that can be caused by freezing, thawing, thermal expansion and contraction, and salt deposition. Direct spraying of water onto masonry can cause mechanical damage and spalling. Spalling can be described as crumbling or flaking at the masonry’s surface.
Salt spalling is a specific type of weathering that can occur in brick, natural stone, tiles and concrete. Dissolved salt is carried through the material in water and then crystallizes inside the material near the surface as the water evaporates. As the salt crystals expand, this builds up shear stresses that break away and create spalling at the surface.
The Barrie Home Inspector has the training and experience to properly identify masonry deficiencies in your home. Some of the issues with masonry includes settlement and shrinkage cracks. Cracks are commonly found at lintels. When a lintel develops rust, the steel expands and pushes up on the masonry units of the wall. A rusting lintel can cause horizontal and step cracks in the masonry. The cracks then expand outward from the top corners of door and window openings. When choosing your home inspector remember that experience can not be learned.
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