Glossary

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Air entrainment:
Minute bubbles of air are introduced into concrete to improve its durability under freezing conditions: the bubbles provide room for moisture to expand into when it freezes, thereby reducing the stresses generated in the concrete.

Anodized:
A process in which a metal object is placed in an acid bath and an electrical current is passed through the tank. The process gives the metal a thin protective and lustrous film. The process is commonly used on aluminum.

Bedding mortar:
The mortar in which the stone or brick is set. The bedding mortar may be physically different than the pointing mortar, especially in terms of its colour.

Brazing:
A form of soldering that utilizes alloys to join metals. The melting point of the alloy is lower than the metal.

Check:
A lengthwise separation of the wood that usually extends across the annual growth rings and commonly results from stresses set up in wood during seasoning.

Cold joint:
A joint or discontinuity formed when a concrete surface hardens before the next batch of concrete is placed against it. The cold joint will be a weak point in the concrete casting.

Consolidant:
A product that is introduced into a crumbling or deteriorating material to make up for the loss of naturally occurring binding agents.

Crack control joint:
A joint created in the concrete casting, often by cutting a groove in the concrete, that is intended to encourage cracking due to shrinkage at that specific location.

Cross crack:
Cracking in a direction that is across the grain of the wood.

Exfoliation:
A process in which the surface material of a stone or brick sheds or sloughs off as a result of an ongoing deterioration in the integrity of the stone or brick.

Exposed aggregate finish:
A special finish for concrete, where an aggregate is deliberately exposed on the surface of the concrete casting. The aggregate is most often a pea-stone or small sized stone.

Fruiting body:
The visible organ of fungi in which the spores are produced, commonly seen as bracket fungi, which grow like shelves on trees, or molds.

Joint profile:
The shape of the mortar joint. The joint profile can be flush or recessed and can vary depending on the shape of the tool used to finish it. The ability of the mortar joint to shed water away from the masonry (rather than directing it into the masonry) is an important design consideration.

Mock-up:
A full size model of a repair or replacement used for testing and reference during work for quality assurance purposes. Mock-ups are prepared at the start of work and can often form part of the finished project.

Oxidation:
A reaction of a metal with oxygen, usually resulting in the degradation of the metal. Oxidation can result in the formation of a protective layer, such as a patina or tarnish.

Permeability:
A measure of a material's ability to transmit fluids.

Pointing mortar:
The mortar that is used to finish the face of the exposed mortar joint. Pointing mortar will often have a different colour and texture than the bedding mortar for aesthetic reasons.

Slurry:
A thin watery mixture of concrete paste applied to a concrete surface to improve bonding between the existing and new concrete.