Applying polyurea coating to line a concrete bund in preparation for new transformer at Willesden Substation

Published: 12 July 2024

The problem

We received a request to assess waterproofing needs in a transformer bay at Willesden Substation. We were asked to attend site promptly as the aim was to have all necessary work completed within a month of the initial contact.

Upon visiting site, we found a concrete bund where the old transformer had been removed. The front wall of the bund had been demolished to facilitate the removal. This demolition was part of the site plan, as the new transformer (scheduled for imminent delivery) would be installed using the same access route.

Given the status of the infrastructure, the scope of work was defined as creating an impermeable solution for the area where new equipment would be installed. Once equipment installation was completed, the front wall of the bund could be rebuilt, prompting our reattendance to deliver our solution to the remaining areas.

The solution

We attended the site and applied our polyurea coating to the area where the new equipment would be installed. Our polyurea coating has a drying time of less than 5 seconds, and when fully cured creates a highly flexible coating combined with excellent tensile strength, increasing its durability and resistance to abrasion.

To prepare the area, our team used a concrete floor scabbler to remove old coatings and repair badly worn concrete surfaces. We then high-pressure jetted the entire area to remove contaminants and loose material. We managed waste disposal internally, avoiding the need for third-party involvement.

After the area dried, localised repairs were carried out using polyurethane sealant and epoxy-based, high-strength repair mortar.

Next, we primed the entire area by applying a rapid-cure concrete primer by hand. Sensitive areas were masked off, and our polyurea coating was applied to the area to a thickness exceeding 2000 microns using our integrated plural component proportioning system.

Finally, we sealed all edges with a neat bead of polyurethane sealant.

Project outcomes

We were mobilised to site to deliver the necessary works 7 days after completing our initial assessment. Due to the urgent equipment delivery, we completed the work in 5 consecutive days.

Our client now has confidence that the area is impermeable and ready for equipment installation. Once the equipment is in place and the front bund wall is rebuilt, we’ll return to finalise the remaining areas, providing a full containment solution for years to come.

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