Waterproofing Basements – How Eastern Ontario Hospital Plans to Stay Above Water
Hawkesbury District & General Hospital is a patient-centered, bilingual community hospital located in Hawkesbury, Ontario. It provides a full range of programs that serve the Prescott-Russell area in eastern Ontario. As a bid to become a full service regional hospital by the end of 2018, HGH has set in motion plans to complete two building additions. These additions are three-stories tall with the inclusion of basements and will ensure more bed space, expanded healthcare services and room for state-of-the-art diagnostic equipment.
There is only one problem – with ground level consisting of a substrate composed of solid rock and gravel on top, there would be no place for accumulated ground water to go, except to seep through the concrete and into the building damaging everything in its destructive path!
In order to counter this problem, a building design was required that would keep the groundwater out of the basements. Following a discussion on how to mitigate the groundwater issue, project architect Erskine Dredge & Associates Architects Inc. received three recommended products from W.R. Meadows field representative, Glen English. These products are: PRECON, MEL-ROL LM and MEL-DRAIN 5035-B.
As stated by English, “Our products were specified in the plans because they could do the job. Each product would have a specific role to play.”
The footprint of the additions total around 48,000 square feet. In order to protect the basement floor from the underground seepage of water, PRECON sheeting was used. By placing the sheeting on the bare ground, the PRECON sheeting would provide a waterproof barrier where the concrete it then poured over top of the sheeting. As discussed by Scott Watson, the construction superintendent for the project, “PRECON was used under the entire basement floor and is a full-blown barrier. It is much better than the old poly or plastic we previously used.” He continued, “It is applied on its own and needs nothing else, and reals really well, creating what I call the ‘bathtub’ effect.”
The concerns about water damage from directly underneath the basement floor were not the only issue, however. The foundation walls are also in need of protection. Again with no place for accumulated groundwater to go, it could build up against the foundational and seep through the concrete walls. To eliminate this problem, two additional products were recommended: MEL-ROL and MEL-DRAIN 5035-B.
The MEL-ROL acts as a sealant when applied directly onto concrete. It is a single-component, water-based waterproofing membrane and has positive reviews in the field with respect to reliability. The MEL-DRAIN then, is a rolled matrix drainage system that is installed after the MEL-ROL is applied to the foundation wall. Moisture is able to pass through the fabric while simultaneously preventing fine soils from entering the drainage channel due to its geo-composite make-up.
Watson noted, “These products are the ideal choices to protect the walls. When the ground water flows toward the foundation, the dimples in the MEL-DRAIN catch it. Gravity then pulls the water down towards a drainage pipe and it flows away from the building.”