3mm Aluminium Flat Coping – 90° T-Junction | 75mm External Leg

On wider parapet walls, typically from 510mm upward, the coping system needs a heavier gauge to maintain rigidity across the span. At a T-shaped wall intersection where three coping runs meet, the junction piece carries the greatest load and spans the widest area. A 2mm T-junction may flex on a wide commercial parapet. The 3mm version provides the additional rigidity needed to keep the coping flat, stable and windproof at the most complex point in the system.

This 3mm aluminium flat coping T-junction connects three coping runs at a 90 degree T-shaped intersection, maintaining a weathertight seal across all three directions. It is powder coated in the same RAL colour as the coping lengths, uses the same concealed fix bracket system, and is fabricated at our Chelmsford, Essex workshop. On commercial buildings, schools, apartment blocks and industrial units across the South East, this is the heavy duty fitting that holds the coping system together at every T-junction.

Product Overview

The 3mm aluminium flat coping T-junction from Online Metal Store Ltd connects three coping runs at a T-shaped parapet wall intersection. The 75mm external leg matches the standard leg dimension across the 3mm flat coping range. Available in 23 width options from 510mm to 1060mm, covering wider commercial parapet walls. Custom fabricated and powder coated in any RAL colour.

For narrower domestic walls (under 510mm), see the 2mm flat coping T-junction which covers widths from 185mm. For standard changes of direction, see the 3mm coping 135° corner. Browse the full aluminium copings collection.

Key Benefits

3mm Heavy Duty Gauge for Wide Parapet Walls

The 3mm thickness provides 50% more rigidity than the 2mm version. On wider parapets (510mm and above), this additional gauge prevents the coping from flexing or drumming in wind. The T-junction spans the widest area of any fitting in the coping system, so the heavier gauge matters most here.

Connects Three Coping Runs at One Point

Factory formed to connect the main coping run with a branch wall from one side. Creates a clean, weathertight transition at the intersection without multiple site-cut joints.

75mm External Leg for Consistent Profile

The 75mm downstand matches the standard leg dimension across the 3mm flat coping range.

23 Width Options for Commercial Walls

Available from 510mm to 1060mm, covering the wider parapet walls found on commercial buildings, apartment blocks and industrial units.

Concealed Fix Bracket System

Supplied with fixing brackets. The coping clicks down onto the brackets with no visible screws.

Powder Coated in Any RAL Colour

Colour matched before dispatch.

UK Manufactured

Fabricated at our workshop in Chelmsford, Essex.

Technical Specifications

Material: 3mm aluminium (heavy duty)

Type: Flat coping 90° T-junction (tee piece)

External Leg: 75mm downstand

Available Widths: 510mm, 535mm, 560mm, 585mm, 610mm, 635mm, 660mm, 685mm, 710mm, 735mm, 760mm, 785mm, 810mm, 835mm, 860mm, 885mm, 910mm, 935mm, 960mm, 985mm, 1010mm, 1035mm, 1060mm

Finish: Polyester powder coated in any RAL colour

Fixing: Concealed bracket system (brackets supplied)

Fire Classification: A2-s1,d0 under BS EN 13501-1

Manufactured: Chelmsford, Essex, United Kingdom

Price: From £118.80 ex. VAT (£142.56 inc. VAT)

2mm vs 3mm Coping T-Junction: Which Do I Need?

2mm T-Junction

Suitable for narrower domestic and light commercial parapet walls. Width options from 185mm. Lower cost. See the 2mm flat coping T-junction.

3mm T-Junction (This Product)

Designed for wider commercial parapet walls from 510mm. The heavier gauge prevents flexing on wide spans and provides greater wind resistance. Choose 3mm when the wall width exceeds 500mm or when the specification calls for heavy duty coping.

How to Fit a 3mm Aluminium Coping T-Junction

Fix the supplied brackets to the top of the wall at the T-junction intersection. Apply EPDM seal tape to the brackets. Click the T-junction piece down onto the brackets, ensuring it seats firmly and aligns with the coping runs on all three sides. Leave a 2 to 3mm expansion gap between the T-junction and each adjoining coping length.

Ensure the waterproof membrane underneath is correctly detailed before fitting. For full step by step guidance, see the how to install aluminium coping guide.

Where 3mm Coping T-Junctions Are Used

Commercial Buildings with Wide Parapets

Office blocks, retail units and industrial buildings with parapet walls over 500mm wide. The 3mm gauge provides the rigidity needed at T-junctions on these wider spans.

Apartment Blocks and High Rise Residential

On apartment buildings across Chelmsford, Brentwood, Colchester and the South East where the parapet is a prominent architectural feature. The A2-s1,d0 fire classification makes 3mm aluminium coping suitable for buildings of any height.

Schools and Public Buildings

On publicly funded projects where heavy duty specification and long service life are requirements.

Frequently Asked Questions

What is the difference between 2mm and 3mm coping T-junctions?

The 3mm version is 50% thicker, providing greater rigidity on wider parapet walls. The 2mm version is suitable for narrower walls (from 185mm). The 3mm version starts at 510mm width and is designed for commercial applications where the wider span needs a heavier gauge. See the 2mm T-junction for narrower walls.

When do I need a 3mm coping T-junction?

When the parapet wall width exceeds 500mm, when the specification calls for heavy duty coping, or on exposed commercial buildings where wind loading is a concern. For domestic walls under 500mm, the 2mm version is usually sufficient.

What size 3mm coping T-junction do I need?

Measure the wall thickness and select the matching width from the 23 options (510mm to 1060mm). The overall coping width includes the 75mm downstand and returns on each side.

How do you fit a 3mm coping T-junction?

Fix brackets to the wall top. Apply EPDM tape. Click the T-junction down. Leave a 2 to 3mm expansion gap on all three sides.

Can the 3mm coping T-junction be colour matched?

Yes. Powder coated in any RAL colour.

Part of a Complete Flat Coping System

The 3mm T-junction is one fitting in the heavy duty flat coping system:

• 3mm Flat Coping 3m Length – main coping length

• 3mm Coping 135° Corner – change of direction

• 3mm Coping T-Junction – this product

• Coping Bracket – concealed fixing bracket

Browse the full aluminium copings collection. The coping system works alongside aluminium fascia and soffits, drip trims and the full rainwater goods range. For a completed project, see the Mellish Street coping case study.

Standards and Compliance

The powder coat finish is applied in line with BS EN 12206-1 for powder organic coatings on aluminium. The coping system achieves a fire classification of A2-s1,d0 under BS EN 13501-1, making it non-combustible and suitable for buildings of any height including high rise residential over 18 metres.