Building Defects

The performance of modern buildings is an increasingly complex subject. However, there are several fundamentals that can be applied to defects, patterns of defects and adequately managing risk.

Due to varying site conditions, almost all buildings are essentially “one-off prototypes” and, in many ways, it is understandable very few are delivered in perfect condition with no apparent or unnoticed defects. Construction defects occur when finished or partially completed buildings fail to perform as required by applicable contract documents or established standards or codes.

Modern structures, especially with the wide range of climactic conditions we experience in Canada, are extremely expensive. In cases where they fail to function as intended – or demonstrate defects – there are also legal and financial implications that can be significant.

There are a number of issues involved with moisture penetration and/or accumulation within the building envelope (walls, windows and roofing systems), which have risen dramatically over the past 20 years.

Increasing construction cost

The cost of construction, operation and maintenance of buildings will continue to increase over time. As a result, the general trend towards seeking legal recourse regarding building defects will likely accelerate in tandem. These are both serious concerns for the both the insurance industry and the construction sector as a whole. The costs involved in rectifying defects in new and existing construction involve the interests of risk managers, brokers, adjusters and insurance companies.

Catastrophic failure

In most cases, projects that experience catastrophic failure receive much greater attention than buildings that experience routine claims for defective construction. Take, for example, the estimated 50,000 condominium units that experienced severe water leakage in British Columbia. These have been identified as catastrophic failures due to water penetration. The cost to repair the defects related to drainage ranges from $40,000 to $60,000 per unit on average.

At the present time, however, Canada, and a number of other countries, are actively investigating ways and means to improve the overall performance of their construction industries on an on-going basis.

Unintended deviations

Unintended deviations from standardized building practice have a significant impact on quality control and are often not identified until the project is underway or completed. In addition, many buildings have defects that may not be immediately apparent when they are put into service, as was the case of the condominiums in British Columbia.

In many cases, inadequate understanding of the building code, lack of knowledge and experience regarding good building practice(s) have been identified as concerns. Another cause that leads to cost and time overruns related to repair of construction defects is rework.

On some projects, cost overruns or defects can be traced to lack of communication between the client, designer and the end-user.

The failure to properly commission the building is also a common omission.

Time is money

In the construction sector the concept that time means money is a fact of life. As a result, over the past 20 years there has been a significant compression of design and construction schedules. This compression results in overlap of activities and increases the chances of time and cost overruns, which magnifies the potential for the occurrence of defective construction.

Construction defects

Claims for deficiencies in the building envelope systems (primarily related to moisture penetration or accumulation within walls, windows, roofing and foundations) have increased dramatically and now comprise approximately 70 per cent of all identified defects. Moisture damage of this nature is considered to be one of the most problematic issues in the industry.

However, in spite of the fact that there are ways to prevent these moisture problems, measures to prevent moisture damage have not been widely adopted. This is primarily because of cost-cutting and failure to undertake design reviews, mock-up testing and adequate on-site quality control.

Many building professionals also believe the failure to apply well-established building science principles before and during construction also leads to non-conforming construction and defects. In many cases, the defects are either not noticed or overlooked, leaving insurance professionals at risk for repairs that become apparent at some point in the future.

Modern building envelope construction

Unlike the solid robust masonry walls that were used in construction in the past, modern building enclosures now often consist of multiple layers of lightweight construction materials. As a rule, each layer serves a very specific function.

In order to avoid or eliminate water penetration or absorption, careful detailing and construction is essential to ensure adequate performance. These items must also take into account the complexity of using these principles for the wide range of climate conditions in Canada.

When undertaking detailed inspection, a lack of continuity is observed. This results typically from using four different layers and because there are numerous interruptions, transitions or penetrations at wall/window intersections. The ‘interface’ of materials is always prone for error.

Many modern buildings use sealants around such penetrations (face seal construction) and sealants do not reliably or adequately accommodate differential movement over the required service life of the assemblies.

Risk and cost reduced

Building science and engineering professionals estimate the cost of defects in new construction represents approximately 10 per cent of building value. There is general agreement that the potential exposure (if claimed) could be greatly reduced by utilizing a combination of accepted techniques. These would include application of accepted building science principles, (including adequate on-site quality control measures) and enforcing existing building code regulations.

Defects could also be prevented by undertaking much closer review of the design and schedule during the building permit application process.

In our experience, the insurance industry can guard against losses due to repairing defects in new and existing construction by anticipating the pattern of defects, adequately managing their risk and by thoroughly evaluating claims for defects to let the fault lie where it may.

Stephen Blaney is president and John McGlone is a principal engineer at Kleinfeldt Consulting Limited (KCL).