3mm Aluminium Coping – 90° Internal Corner | 125mm External Leg

Easily join internal wall corners with a robust coping corner unit made for long-term protection.

This 90° internal corner unit is built to connect two coping runs neatly at an internal angle, delivering a secure and watertight fit. Crafted from strong 3mm 1050A-grade aluminium, it offers excellent durability while maintaining a clean finish. The 125mm external leg gives added wall coverage, while the polyester powder-coated surface protects against rust, UV damage, and wear. Ideal for both commercial and residential builds.

Please refer to the attached RAL colour chart to view available options. At checkout, enter your chosen RAL colour in the designated box.

Choose a variant:

Size (Capping Width)

Starting at £122.88

excluding shipping cost

Download Colour Chart

Features + Benefits

Pre-formed 90° internal corner for smooth coping alignment
Heavy-duty 3mm aluminium for lasting performance
125mm external leg offers deeper wall coverage
Fire-rated A2-s1,d0 for full building compliance
Powder-coated finish resists corrosion and fading
Push-click system with concealed brackets
Seamlessly connects with sloping coping lengths
Supplied with 1.5nr fixing brackets per unit
Available in full RAL and BS colour range
100% recyclable and UK manufactured

Specs & Options

Angle: 90° Internal Corner
Material: 1050A Grade Aluminium
Thickness: 3mm
External Leg: 125mm
Internal Leg: 75mm
Finish: Polyester powder-coated (external grade)
Fire Rating: A2-s1,d0
Colours: RAL/BS colour options available
Fixings: 1.5nr hidden brackets included
Lead Time: 5 to 10 working days
Custom Sizes: Available on request

Installation / Usage Instructions

Fix the brackets to the wall or plywood upstand at the 90° junction. Apply EPDM tape for sealing. Push-fit the corner unit into place, leaving a 3mm expansion gap to connect with the adjacent coping runs.

Need a clean and durable way to connect internal coping angles?