Solihull Preparatory School - Alice House

PROJECT REQUIREMENTS

The original roof comprised 9mm plywood, with a saturated insulation layer and felt covering. This construction no longer met modern building regulations, necessitating a comprehensive upgrade to reinstate a functioning roof system.

SIKA SOLUTION

The first stage involved stripping the existing felt and insulation back to the original plywood deck. The team then installed 18mm OSB tongue-and-groove boards, providing a sound substrate capable of supporting the upgraded insulation and roofing system.

Following this, an air and vapour control layer (AVCL) and 130mm of modern insulation was installed across the roof, significantly improving thermal performance in line with current regulatory requirements. A carrier membrane was installed above the insulation, followed by the application of Sika® Decothane® Ultra, a low-odour liquid-applied waterproofing system. 

The completed system not only ensures long-term waterproofing but also meets the enhanced thermal standards expected in modern construction, providing a safe and energy-efficient environment for the school’s learners.

This project highlights Maker Construction Ltd’s expertise in executing complex waterproofing and insulation upgrades, and managing works in a sensitive educational environment, as well as Sika’s® robust product portfolio. The project was completed within a five-week period, a full week ahead of the anticipated programme timeframe, demonstrating efficient planning and delivery.

The Alice House project presented several logistical, structural, and operational challenges. The works had to be carried out during the summer holidays, providing a narrow five-week window to complete a full roof replacement. The building had recently undergone internal refurbishment on the upper floors, with new ceilings and carpets already installed. It was therefore critical to maintain watertight conditions every night, ensuring that the completed internal finishes were protected throughout the works.

The roof also featured drain outlets and an area prone to ponding, which posed a risk of water accumulation. Makers Construction Ltd worked with Sika® and the schools design team to incorporate a sump system, channelling water towards the drain outlets, eliminating standing water, while preserving the roof's structure and thermal performance.

The completed roof at Alice House represents a significant transformation. The upgraded insulation and Sika® Decothane® Ultra roof waterproofing system provided a clean, uniform finish, enhancing both the durability and visual appearance of the building.

Curved edges around the perimeter were executed with precision, creating smooth transitions that complement the building’s timber-framed architecture. The finished roof not only improves functionality but also visually elevates the school building, ensuring a professional appearance that aligns with the school’s standards.