Below-Grade

Al Mashfa Private Hospital
Jeddah, Saudi Arabia

BACKGROUND
The Al Mashfa Group, a much-respected medical company, built an 10-storey full-service private hospital in Jeddah just one kilometre from the banks of the Red Sea. The project team excavated a 12-metre (39.4 feet) pit (for a two-level parking garage beneath the hospital) in a mixture of soil and sand that had a high concentration of sulphates due to its proximity to the Red Sea. Salt water and its ability to corrode the steel and compromise the integrity of the structure was a key concern for the cold joints, as was extreme head pressure – 92 metres (301.8 feet)! The team also hit an underground lake that was too large to pump out, which meant the team required a waterproofing solution that could be installed in wet conditions. Finally, construction of the hospital was already behind schedule; the project team could not afford further costly delays.

SOLUTION
The Al Mashfa project team compared traditional membrane systems – costly and labour intensive methods vulnerable to human error – with the Krystol Concrete Waterproofing System, a worldwide leader in crystalline waterproofing technology. The team discovered that in addition to employing Kryton to completely waterproof and tank the hospital, they would also save time and thousands of dollars (less than $1.50 per square foot) in waterproofing and cold joint construction.

The Krystol system employs advanced integral crystalline waterproofing technology to transform porous concrete into a permanent, water-resistant barrier and provides a guaranteed defense against water damage and steel reinforcement corrosion through constant head pressure. When combined with water and concrete, Krystol causes millions of needle-like crystals to grow and spread concrete particles to permanently block the movement of water and waterborne contaminants. If cracks form later on, incoming water causes additional crystals to grow, filling the cracks and ensuring that the structure’s waterproofing barrier is protected.

Krystol technology provides maximum flexibility and can be used any time before, during or after the construction process. It can be applied in wet or dry conditions, and unlike external waterproofing membranes originally specified for the Al Mashfa Private Hospital, Krystol will not deteriorate – it is guaranteed to last the lifetime of the structure.

“The implementation of all typical waterproofing methods would have been near impossible for our project,” said Mr. A. Hamis Elmas, Project Manager & Architectural Consultant, Al Mashfa Group. “Particularly given the challenges we incurred during excavation: the 12-metre (39.4 feet) cutoff wall and extreme head pressure. We required an advanced waterproofing system that could withstand all of these obstacles especially during the casting of the matt slab.”

The Krystol Concrete Waterproofing System at the Al Mashfa Private Hospital included:

• Krystol Internal Membrane HS (KIM-HS), an admixture suitable for new concrete construction. KIM-HS was used in the 1.6m-thick (5.2 feet) basement slab, along the slab perimeter and in the walls.
• The Krystol Waterstop System (KWS), an advanced joint design system that provides both chemical and physical waterproofing barriers. KWS was used in all the cold joints of the slab and walls.

Predictably, when the team first turned off the dewatering pumps, water trickled in due to the intense head pressure. However, after a few weeks, Krystol’s crystalline technology self-sealed and left the structure dusty dry.

“I can say with complete confidence that if Kryton had not been involved in this project, we would still be looking for a waterproofing solution that would meet the demands of our project. I will specify Kryton on all my future projects,” said Mr. A. Hamis Elmas, Project Manager & Architectural Consultant, Al Mashfa Group.

More than 25,215kg (55,589 lb) of KIM-HS® treated 6,413 cubic metres (21,040 cubic feet) of concrete covering an area of 4,045.5 square metres (13,272.6 square feet). Over 551 lineal metres (1807.7 lineal feet) of KWS™ was used for all the cold joints. The Al Mashfa Group saved 48 days by employing the Kryton concrete waterproofing products.

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The team hit an underground lake that was too large to pump out, which meant they required a waterproofing solution that could be installed in wet conditions.

“I can say that if Kryton had not been involved in this project, we would still be looking for a waterproofing solution.” Mr.
A Hamis Elmas, Project Manager & Architectural Consultant, Al Mashfa Group