Builder Bulletin

In June and July, NHWICC conducted presentations across major cities in Alberta titled “Expansive Clays and Residential Construction – Characteristics, Issues, and Practices to Mitigate Structural Defect Claims.” These sessions aimed to disseminate extensive knowledge accumulated from numerous geotechnical investigations, structural claims, and historical events related to moisture-sensitive soils in high-fill and expansive soil conditions. The outcome is to provide effective mitigation solutions to prevent future claims and significantly reduce the escalating claim and builder costs associated with soil settlement or heaving. 

Builder Responsibilities

As a member of ANHWP, you assume the role of an Accredited Representative, which includes ensuring that homes are constructed in a good and workmanlike manner, compliant with the Alberta Building Code. It is crucial, and a code requirement for builders to assess the soil conditions of each lot and implement measures to mitigate the impact of moisture-sensitive soils on the home.

Key Insights

Our presentations highlighted the prevalence of moisture-sensitive soils throughout Alberta, especially in new developments, as cities expand. It is essential the industry accepts this “New Norm” and adopts the recommendations from Geotechnical Reports and mitigation strategies suggested by the engineering community and ANHWP. These measures are vital to protect new homes built on high-fill or moisture-sensitive soils from significant displacement due to water infiltration beneath the basement slab and footings.

Indemnity Period and Structural Claims

The current reduced indemnity period covers structural claims arising from unforeseeable events not attributed to design, workmanship, or construction components. If a valid structural claim related to moisture-sensitive soils is made, NHWICC will require the builder to contribute to the repair costs, including engineering, underpinning, and cosmetic repairs beyond the indemnity period, unless it can be demonstrated that the geotechnical recommendations or mitigation options were implemented during construction.

Resources and Recommendations

Below is a copy of the presentation and Builder Protocol, offering several options to consider when constructing new homes to minimize costly repairs, future structural claims, and stress for homebuyers. We strongly recommend discussing these options with your engineering, design, and construction teams to determine the best solutions for your projects. For additional information and assistance, please contact Peter Gogich, C.E.T., at NHWICC.