When a concrete surface shows minor defects, bug-holes, or an inconsistent finish, the goal is a rapid, smooth, and durable cosmetic repair. It needs to disappear under an architectural coating or stand alone as a uniform surface. The RLA Penapatch Fairing Coat Mortar achieves this. It provides a fine-textured, fast-setting compound for thin-layer repairs, delivering a consistent, ready-to-coat finish. The right product ensures the surface looks right, every time.

Why this product exists

RLA Penapatch Fairing Coat Mortar was specifically formulated to address surface imperfections on concrete and masonry. It delivers a fine-textured, polymer-modified cementitious compound that repairs cosmetic defects and provides a smooth, uniform finish up to 5mm thick. Its design prioritises excellent adhesion and negligible shrinkage, preventing common issues like telegraphing imperfections through subsequent architectural coatings or finishes. This compound creates a durable layer that can either be over-coated or left exposed for a clean, architectural look.

The numbers that matter

This fairing coat mortar is engineered for precision and rapid results. Its ability to be applied up to 5mm in a single layer means precise feather-edging and thin-build repairs are achievable without slumping. A fast initial set time of 25 minutes at 20°C allows for quick turnaround, while reaching 4 MPa compressive strength in 1 day and 20 MPa in 28 days (tested to AS1012 & AS2073) ensures a durable repair that resists impact and wear. Crucially, drying shrinkage is less than 300 microstrain at 28 days (tested to AS 1012.13), minimising the risk of reflective cracking and maintaining a consistently smooth finish under coatings.

What it's like to use

RLA Penapatch Fairing Coat Mortar is designed for straightforward application. Mix a 20kg bag with 5.9 – 6.0 litres of clean water using a drill mixer until a smooth, soft mortar consistency is achieved. Work within the 25-minute initial set time, applying the mortar by trowel to the required thickness, feather-edging where necessary. The product is workable between 5°C and 35°C; adjusting water temperature can help manage working time in extreme conditions. For highly porous surfaces, or to assist with curing in warm, windy conditions, RLA recommends using RLA Rendergrip A as a primer or curing agent to reduce flash drying and premature setting.

Where this product excels

This fairing coat mortar is ideal for situations demanding a superior aesthetic finish on concrete and masonry surfaces:

  • Architectural Concrete Finishing: Perfect for infilling surface imperfections, bug-holes, and tie holes on exposed concrete, ensuring a smooth, uniform texture that enhances the final appearance.
  • Vertical Fairing Applications: Suitable for columns, beams, and soffits, where its excellent adhesion and negligible shrinkage prevent slumping and maintain a crisp, plumb finish.
  • Over-Skimming Existing Repairs: Can be applied over other RLA mortars to provide a consistent surface texture, preparing the area for subsequent protective coatings or decorative finishes.
  • Precast Panel Refinishing: For precast elements requiring minor touch-ups or an enhanced surface before delivery or installation.

Choose this when

  • When you need a smooth, uniform finish on concrete: For cosmetic repairs, bug-holes, or tie holes that will be coated or left exposed.
  • For thin-layer repairs: When the maximum repair thickness required is 5mm in a single application.
  • When rapid setting is beneficial: Its fast-setting properties allow for quick project progression and overcoating within 48 hours.
  • For vertical and overhead applications: Its workability and adhesion support non-slumping application on columns, beams, and soffits.

Don't use this when

  • Not for: Areas subject to rising dampness or continuous wet exposure, as this can compromise bond strength and durability.
  • Not for: Applications exceeding 5mm in a single layer. For deeper repairs, consider a bulkier repair mortar.
  • Not for: Structural repairs where significant load-bearing capacity is required. This product is for cosmetic and non-structural defect rectification. For structural repairs, investigate options like Mapei Mapegrout T40.
  • Not for: Substrates that are prone to movement or cracking, as reflective cracking will likely transfer through the fairing coat.