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Metal roof repairs are plain sailing at Admiral Lord Nelson School thanks to Sika Pro-Tecta

Named the TES ‘Creative School of the Year’ in 2019, Admiral Lord Nelson School in Portsmouth is a high school for around 1000 pupils aged 11-16. The school operates from a striking white building that reflects its maritime location with a cruise ship-style design.


The building was constructed in the 1990s and features a standing seam metal roof. Due to integrity issues across a number of roof areas, dating back to the original build programme, the school was experiencing problems with water ingress. This was causing secondary damage to the internal fabric of the building. A roof refurbishment was required to provide a complete waterproofing solution for the whole roof and this has been carried out as a phased project alongside a programme of internal refurbishment.

Specifying the Right System

Working with building surveying practice, Kendall Kingscott, the school intended to secure funding for the roof refurbishment through the Government’s Condition Improvement Fund (CIF). In order to submit a successful bid, a system with a guaranteed service life of 15 years was required, making the Sika Pro-Tecta waterproofing (WP) system, with its range of guarantees, an ideal solution.

Sika Pro-Tecta also provided a system designed specifically for robust protection of metal roofs and capable of addressing the water ingress issues by encapsulating all the roof details and the metal sheets.

The project commenced during the school’s six-week summer break but, due to the size of the roof, the majority of the work had to be delivered during term time, while enabling the school to continue to operate as usual. Consequently, the speed of installation offered by the Sika Pro-Tecta WP system was also a major benefit.

Expert Installation

Sika Liquid Plastics’ Quality Assured (QA) contractor, Davis Roofing, Kendall Kingscott and Sika Liquid Plastics Area Technical Manager carried out a full inspection of the existing roof to assess the project’s requirements. Sika Liquid Plastics worked with the building surveyor and the school to develop the bid.
The Davis Roofing team began by removing all the existing aluminium detailing and cleaning and preparing the roof, applying the high-performance Sika Poxicolor HE New metal primer to the roof surface.

All detailing was then reinforced using Sika Joint Tape SA for all ridge, hip, apron, eaves and gutter details. The tape was also used to reinforce a total of 5300m of seams on the standing seam roof. A light flash coating of Sikalastic 625 cold-applied liquid membrane was then applied to all reinforced detailing and seams.

The Sika Pro-Tecta WP system was completed with a full encapsulation of the roof with Sikalastic 625.

The specification for the roof refurbishment also included replacement of three electrically operated lantern lights and five polycarbonate roof lights, with supply co-ordinated by Sika as part of a turnkey product and service package.

Joe Robbens, Commercial Manager at Davis Roofing, comments: “The roof at Lord Admiral Nelson School is very large and has a lot of detailing that needed to be reinforced before we could begin waterproofing with the Sikalastic 625. The Sika Pro-Tecta system’s Sika Joint Tape SA made this process much faster than it would have been using traditional reinforcement techniques, which provided labour cost savings for us and faster project delivery for the client.”

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