Know the Building Materials Used in Residential Construction
The integrity of any ‘thing’ is determined by the strength or weakness of its foundation! Without one, every “thing” crumbles.
The following materials are the basic components of any residential structure: the foundation footing, the foundation walls, and the basement floor. With an understanding of the materials, you’ll have a better understanding of how your home was constructed, and subsequently, why you have problems with moisture or other issues.
Cement is a binding substance that sets and hardens independently, and can bind other materials together. Cement should not be confused with concrete as the term cement explicitly refers to the dry powder substance. Upon the addition of water and/or additives, the cement mixture is referred to as concrete, especially if aggregates have been added.
The word “cement” originates back to the Romans, who used the term “opus caementicium” to describe masonry, which resembled concrete and was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick additives, which were added to the burnt lime to obtain a hydraulic binder, were later referred to as cementum, cimentum, cäment, and cement. Cements used in construction are characterized as hydraulic or non-hydraulic.
Hydraulic cements are materials that set and harden after being combined with water, as a result of chemical reactions with the mixing water, and that, after hardening, retain strength and stability even under water. The key requirement for this strength and stability is that the hydrates formed on immediate reaction with water be essentially insoluble in water.
Most construction cements today are hydraulic, and most of these are based on Portland cement, which is made primarily from limestone, certain clay minerals, and gypsum in a high temperature process that drives off carbon dioxide and chemically combines the primary ingredients into new compounds.
Non-hydraulic cements include such materials as non-hydraulic lime and gypsum plasters, which must be kept dry in order to gain strength, and oxychloride cements, which have liquid components. Lime mortars, for example, “set” only by drying out, and gain strength only very slowly by absorption of carbon dioxide from the atmosphere to re-form calcium carbonate through carbonatation.
The most important use of cement is the production of mortar and concrete – the bonding of natural or artificial aggregates to form a strong building material, which is durable in the face of normal environmental effects.
Concrete is a construction material composed of cement (commonly Portland cement) as well as other cementitious (having the properties or characteristics of cement) materials such as fly ash and slag cement, aggregate (generally a coarse aggregate such as gravel, limestone, or granite, plus a fine aggregate such as sand), water, and chemical admixtures. The word concrete comes from the Latin word “concretus”, which means “hardened” or “hard”.
Concrete solidifies and hardens after mixing with water and placement due to a chemical process known as hydration, by which Portland cement combines with water, giving off heat, which bonds the other components together, eventually creating a stone-like material or crystalline structure in its setting and hardening. Concrete is used to make pavements, architectural structures, foundations, motorways/roads, bridges/overpasses, parking structures, brick/block walls, and footings for gates, fences, poles and your home.
Mortar is a binding agent used in the construction of clay brick, concrete masonry, and natural stone masonry walls and, to a lesser extent, landscape pavements. Modern mortars are improved versions of the lime and sand mixtures historically used in building masonry walls. Masonry mortar is composed of one or more cementitious materials, such as masonry cement or Portland cement and lime, clean sand, and sufficient water to produce a plastic, workable mixture.
Mortars are closely related to concrete but like grout, generally do not contain coarse aggregate. Mortars function with the same calcium silicate-based chemistry as concrete and grouts, bonding with masonry units into a contiguous, weatherproof surface in the process. Masonry cement or Portland cement-lime mortars can be formulated to address job-specific requirements including setting time, rate of hardening, water retentivity, and extended workability.
Concrete Masonry Units (CMU, Cinder Block, Concrete Block)
A concrete masonry unit or foundation block is a large rectangular brick used in construction. Concrete blocks are made from cast concrete, i.e. Portland cement and aggregate, usually sand and fine gravel for high-density blocks. Lower density blocks may use industrial wastes as an aggregate. Those that use cinders (fly ash or bottom ash) are called cinder blocks in the US and breeze blocks (breeze is a synonym of ash) in the UK. Clinker blocks use clinker as aggregate. Clinker is a general name given to waste from industrial processes, such as coke, coal, slag, charcoal, grit, and other waste materials. Concrete blocks that do not contain cinders are often mistakenly called cinder or breeze blocks in everyday speech. Lightweight blocks can also be produced using aerated concrete.
Concrete blocks may be produced with hollow centers to reduce weight or improve insulation. The use of block work allows structures to be built in the traditional masonry style with layers (or courses) of overlapping blocks. Blocks come in many sizes. In the US, the most common size is 8 in × 8 in × 16 in (20 cm × 20 cm × 41 cm); the actual size is usually about 3/8 in (1 cm) smaller to allow for mortar joints. In the UK, blocks are usually 44 cm × 21.5 cm × 10 cm excluding mortar joints (approximately 17.3 in × 8.5 in × 3.9 in).
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 CBS construction for Concrete Block Structure. US suburban houses typically employ a concrete foundation and slab with a concrete block wall on the perimeter.
Brick is a solid masonry unit, usually consisting of clay, molded into a rectangular shape while plastic. It is then treated in a kiln at an elevated temperature to harden it, to give it mechanical strength and to provide it with resistance to moisture. After being removed from the kiln, the brick is said to be burnt, hard-burnt, kiln-burnt, fired, or hard-fired. Bricks laid lengthwise in a wall are called stretchers. Bricks laid crosswise to a wall are called headers. Bricks differ in color, ranging from dark red, pink to blue-black and purple, depending on the type of clay and on the temperature of the kiln in which they were burnt. The current American brick is typically about 8 inches (20.3 cm) long, 3 ¾ inches (8.26 cm) wide, and 2 ¼ inches (5.7 cm) thick. Good bricks are resistant to atmospheric action and high temperatures and are more durable than stone.
Terra Cotta Block and Stone
Terra Cotta block and stone were used in the 19th Century, and early in the 20th Century as material for wall construction. In the late 20th and now in the 21st Century, these products are used as fascia for above grade outside wall facing of brick, stone, etc., providing a decorative, durable surface.