10:30 am - 11:50 am | Room: Owens Corning Room | Session Chair: Jelena Madzarevic

Moisture Management In Buildings

The Rotten Details: Protecting Wood-Framed Structures From Rainwater And Rot

As pressure mounts for affordable housing in Ontario, low-rise wood-framed buildings have grown in popularity. As a result, there is an increasing number of new buildings being constructed with wood balconies and terraces protected by sheet vinyl waterproof membranes. Wood rot due to water penetration at defects or damage in the membrane leads to accelerated wood rot and eventual structural failure. 

Many balconies have top-mounted balcony guards which are fastened through the waterproofing membrane into structural wood blocking or wood framing. Sealant or gaskets are provided at the fastener penetrations or baseplate perimeters to protect against water infiltration; however, sealant imperfections or deterioration allow water to bypass the waterproof membrane at the fastener penetrations and rot the underlying wood structure. The wood rot compromises the balcony guard anchorage and structural integrity of the railing and or balcony itself.

Further, poor detailing of the membrane, including lack of proper waterproofing upturns at transitions, results in water penetration during rain or snow melt conditions. This issue is notable at wood-framed balconies with sliding doors or post penetrations. Making matters worse is that the wood structure is typically concealed by metal capping and soffits and the wood rot and deterioration can become severe and not noticed by residents. Extensive wood deterioration can lead to failure of the guard system and even sudden structural collapse. 

This paper explores the significant performance concerns related to watertightness and durability of wood-framed balconies protected by sheet vinyl waterproofing membranes. Key considerations include attention to details at waterproofing penetrations and terminations, ensuring positive drainage and ventilation for drying, and periodic inspections of concealed structural elements.

Stefan Nespoli, Edison Engineers

Stefan Nespoli, P.Eng., BSS is a Sr. Project Manager and Shareholder in Edison’s Grand River office. He began his career as a contractor and gained valuable experience on condominium, commercial, and hospital project sites in Toronto and Southwestern Ontario before finding his way to Building Restoration consulting over a decade ago. Stefan’s work focuses primarily with condominium clients navigating capital planning and building repair challenges beginning shortly following initial construction.

Shawna Smigelski, Edison Engineers

Shawna Smigelski, P.Eng., BSS is a Project Manager and Shareholder in Edison’s Grand River office. She is responsible for all aspects of project delivery, including building assessments, developing repair strategies and specifications, and construction. Shawna is passionate about finding feasible repair options to tackle her individual clients’ needs, and improving our built environment by developing customized, durable repair solutions. She focuses on educating and communicating with clients to help them make informed decisions.