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construction pathology: construction deterioration & building durability glossary

Construction deterioration & building durability glossary


Article & glossary hosted by A. Sebastian Engineering and Investigation Services

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DAMP COURSE
A course or layer of impervious material which prevents capillary entrance of moisture from the ground or a lower course. Often called damp check.

damp proofing or dampproofing
Prevention of moisture penetration by capillary action. It is achieved by application of materials or by the treatment of surfaces in order to stop (rarely) or to retard the passage of moisture. It allows evaporation from the inside of the building.

damp proof course (D.P.C.) Resistance to the movement of moisture from the ground (or the lower part of the structure) to the upper part through capilliarity.

degradation
Incapability to perform a designated mission.

Design life
is an important quantitative measure that defines the quality of the project. Buildings will not last forever. The owner and designer should establish a reasonable design life for each project. This requires consideration of the economic factors such as initial cost and maintenance costs. The design life will have an impact on the selection of materials, maintenance procedures, and the selected factors of safety.
The expected performance is also an important qualitative measure for the design of the project. The minimum performance level is set by the building code, however, there are aspects of a Structural Brick Veneer System performance that are not explicitly covered by the code and require judgment. It has been useful to define two distinct levels of expected life and performance:
Level 1 (institutional) is intended to signify a high level of quality and long life. Buildings of this type might include public or institutional buildings. Specifically, these are buildings where the additional costs associated with higher quality are judged to be necessary in meeting the overall project requirements.
Level 2 (commercial) is intended to signify a good level of quality and an average design life. Buildings of this type might include general office, industrial, and residential buildings. These are buildings where the additional cost of Level 1 (institutional) quality is not economically justified or necessary. The primary difference in design life is obtained by increasing the quality of the connectors, improving the weather resistance of the materials and expanding on the amount of inspection and testing.

deterioration/di-"tir-E-&-'rA-sh&n, dE-/
Function: noun
Date: 17th century
Do buildings have a shelf life? If yes, then deterioration is the length of time during which an item or element, subject to degradation or having a limited life which cannot be renewed, is considered serviceable while stored (see also storage life). Otherwise, deterioration implies the impairment of usefulness or value.

DOG'S TOOTH
Brick laid with their corners projecting from the wall face.

DRIP
A projecting piece of material, such as a fin or a groove, installed at the outer edge of a sill, or soffit, and shaped to to interrupt the flow of water downward or and prevent its running down the face of any vertical surface or inward across the soffit.

durability/'dur-&-b&l also 'dyur-/
Function: adjective
Etymology: Middle English, from Middle French, from Latin "durabilis", (from "durare" to last; also from Latin "durare" to harden, endure, from "durus" hard)
Something 1. able to exist for a long time without significant deterioration; 2. designed to be durable, such as in "durable goods"; 3. the ability of resisting agents or influences which tend to cause changes, decay, or dissolution
also: du·ra·bil·i·ty /"dur-&-'bi-l&-tE, "dyur-/ noun
du·ra·ble·ness /'dur-&-b&l-n&s, 'dyur-/ noun
du·ra·bly /-blE/ adverb

Durability is not an intrinsic property of a material but depends largely on how a material reacts to a specific environment such as moisture, temperature, ultra-violet radiation, and to the presence of other materials (incompatibility). A material also often sees two different environments during its service life, one during construction and another after the building has been completed. The environment the air barrier sees only briefly during construction may nonetheless be detrimental to the long term performance of some of the materials that compose it. These materials should always therefore be adequately protected from rain, heat, ultra-violet radiation, cold, and mechanical damage during construction.

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