Before undertaking repairs to the balconies or exterior walls of a building condition assessment to determine existing conditions and the nature and causes of poor performance and visible deterioration must be conducted. If this information is not obtained there could be a high risk of the repair failing.
Extent
The extent of the condition assessment depends largely on the aims and objectives of the repair work. The factors that affect the repair objectives include safety and structural integrity, performance and economic service life. Other factors may include changes in the intended use of the building or loading requirements on the exterior walls serviceability, appearance and cost.
A condition assessment of exterior walls of a building is sometimes required been if repairs are not contemplated. For example, a condition assessment may be carried out as part of an on-going program of monitoring to establish the performance characteristics and aging characteristics of the walls. This information would be useful in projecting cash flow requirements in a reserve fund study. A condition assessment is often limited to non-destructive evaluation. Sometimes additional destructive investigation, such a test cuts, is required to confirm or augment the information obtained non-destructively.
Test Methods
Traditionally, a condition assessment consists of a visual examination of the exterior walls together with selective non-destructive tests for compressive strength, absorption, delamination, and other conditions. Newer non-destructive testing methods now available greatly improve the efficiency of the condition assessment process. Some of these recently developed non-destructive evaluation procedures such as the masonry absorption test, allow relatively rapid evaluations of damage and deterioration to be made.
The use of the non-destructive test methods should not be random but should be based on a methodology designed to provide the required information cheaply as possible. This information would usually include the types, locations and extent of the problem conditions being assessed with the sizes of the test samples or areas being consistent with the size of the structure so that the results are statistically meaningful.
Fore, example, determining the soluble chloride ion (salt content) of the concrete forming the balconies of a building at only one or two locations will not provide sufficient data to either draw statistically significant conclusions or the determine the extent if any to which salt was added to the concrete forming the floor slabs and balconies of the building during construction of the extent to which contamination has occurred due to say, salt laden wind borne spray foam from an adjacent street landing on the balcony during periods of a mild winter weather.
Procedure
Before the field investigation work is undertaken, it is important to obtain as much information as possible relating to the original design and construction. This would normally include a review of the structural, architectural and shop drawings project specification and construction records where available as well as a review of the maintenance records. Frequently an assessment of this type begins with a questionnaire distributed to the unit owners or occupants in which is solicited information concerning the performance characteristics of the exterior walls with regard to water penetration, air penetration (drafts), reflections staining, mildew and mold, and during cold weather, condensation characteristics, particularly of the window units. Despite the range of non-destructive testing methods available to investigator, visual inspection still forms the core of any condition assessment and is the main tool available to the investigator.
Records
A visual inspection is conducted at the beginning of the condition assessment and evidence of such items as cracking, spalling, scaling, delamination, corrosion anchor failure and efflorescence are typically recorded in either table form or on drawings specially prepared for this purpose. Photography is also an important component for documenting existing conditions and colour photographs or digital images stored in a database are equally satisfactory for this purpose.
Analysis
The information obtained during the condition assessment should be assessed to determine the causes of the observed deterioration. In addition the implications of the conditions observed must be evaluated to determine their effect on strength, serviceability and durability of the exterior walls. In extreme cases, where analysis of the data reveals structurally significant deterioration has occurred, immediate action may be necessary to ensure the continuing stability and safety of the wall components or sections in question.
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