St John Primary Concrete Repairs – NATCEM® 35

Project – Concrete Repairs at St John Primary School
Product – NATCEM® 35
Contractor – Richardson & Starling

NATCEM® 35 was specified for a series of concrete repairs at St John Primary School in Barrhead, addressing deteriorated as well as damaged structural elements identified during a recent survey.

Project Background

The building, which was constructed primarily from reinforced concrete, had exhibited significant spalling and corrosion, particularly on exposed reinforcement areas across various elevations. Moreover, previous render repairs had de-bonded from the concrete substrate, further accelerating deterioration.

As a result, Cowal Design, which was tasked with designing the remedial works, highlighted the need for a high-performance repair mortar with minimal shrinkage, rapid setting properties, and exceptional durability. Consequently, NATCEM® 35 was selected due to its proven ability to meet these stringent requirements without the need for additional primers.

Scope of Work

The works were conducted in two phases:

Phase 1 – Repairs to the rear elevation, addressing spalling on copes, beams, and lintels.
Phase 2 – Repairs to the left, right, and front elevations, including inaccessible areas, for which allowances were made.

Key tasks included:

• Erecting tower scaffolding to ensure safe access.
• Cutting out deteriorated concrete to expose the reinforcement.
• Cleaning and assessing the reinforcement to determine whether it could be reused or needed replacement, with H8 U-bars and Hilti Hit Re300 resin being used as required.
• Applying NATCEM® 35 in layers, ensuring substrate saturation for optimal adhesion and performance.