2mm Aluminium Fascia – 90° Internal Corner | Type 4

Where a roofline turns inward on a building using the Type 4 fascia system, the inside corner needs to carry all four bends around the 90 degree angle: the top return, the flat face, and the reverse L-return at the bottom. Forming a four bend reverse L-return inside a confined recess on site is not achievable. The reverse return requires precision forming in both directions simultaneously, which is only possible in a controlled workshop environment.

A factory formed Type 4 internal corner arrives powder coated, precisely angled, with all four bends formed to match the parent fascia lengths. The soffit engagement continues cleanly around the inside angle without interruption. On buildings across Chelmsford, Brentwood, Colchester and the wider South East, this is the fitting that maintains the full reverse L-return enclosure at every inward turn.

Product Overview

The 2mm aluminium fascia 90° internal corner from Online Metal Store Ltd is a factory formed corner piece for the Type 4 fascia profile. It connects two Type 4 fascia 2.5m lengths at an inward facing 90 degree angle, maintaining the four bend reverse L-return profile around the corner. Available in the same 14 depth options (150mm to 800mm), custom fabricated at our Chelmsford, Essex workshop and powder coated in any RAL colour.

The depth must match the fascia boards it connects. For outward facing corners, see the Type 4 90° external corner. If your roofline uses a simpler profile, see the Type 1 internal corner, Type 2 internal corner, or Type 3 internal corner. Browse the full fascia and soffits collection.

Key Benefits

Carries All Four Bends Around the Inside Angle

The factory formed corner maintains the top return, flat face, and reverse L-return around the full 90 degree internal angle. The soffit remains fully locked into the reverse return around the inside corner, even in the recess where water naturally collects.

Factory Formed for a Precise Inside Angle

Internal corners are harder to access than external corners, and a four bend reverse L-return is impossible to form in a confined recess on site. The factory formed piece is the only practical option.

14 Depth Options

Available in every depth from 150mm to 800mm, matching the full Type 4 fascia range.

Powder Coated in Any RAL Colour

Every corner is colour matched before dispatch.

UK Manufactured with Fast Turnaround

Fabricated at our workshop in Chelmsford, Essex.

Technical Specifications

Material: 2mm aluminium

Type: 90° internal corner, Type 4 profile (four bend: top return, face, reverse L-return)

Available Depths: 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, 450mm, 500mm, 550mm, 600mm, 650mm, 700mm, 750mm, 800mm

Finish: Polyester powder coated in any RAL colour

Manufactured: Chelmsford, Essex, United Kingdom

Price: From £34.90 ex. VAT (£41.88 inc. VAT)

How to Fit a Type 4 Fascia Internal Corner

Fix the internal corner into the recess at the inside angle, securing it to the rafter tails or fascia backing timber with corrosion resistant screws. Butt the Type 4 fascia 2.5m lengths up against each side of the corner, leaving a 3mm expansion gap at each joint. Cover the joints with colour matched joint covers bonded with low modulus silicone sealant.

Apply a bead of colour coded sealant behind the corner and along the joint lines. Internal corners collect more water than external corners because water runs into the recess, so a clean sealant line is critical. Once the fascia and corner are in place, engage the soffit board with the reverse L-return of the corner to complete the enclosed eaves box around the inside angle.

Where Type 4 Fascia Internal Corners Are Used

Extensions Meeting the Main Building

Where a rear or side extension meets the original building on properties using the Type 4 reverse L-return fascia system across Chelmsford, Brentwood, Basildon and the South East.

L-Shaped Buildings and Dormer Windows

On L-shaped properties and at dormer window junctions where the fascia turns inward. Each side of a dormer cheek creates an internal corner.

Commercial and Exposed Rooflines

On commercial buildings and exposed locations where the Type 4 profile is specified for maximum soffit enclosure and wind resistance, the internal corner keeps the reverse L-return intact around every inside angle.

Frequently Asked Questions

What is a Type 4 fascia internal corner?

A factory formed 90 degree internal corner for the Type 4 aluminium fascia profile. It carries all four bends (including the reverse L-return) around the inside angle. Compare with the Type 1 internal corner (single bend), Type 2 (two bend), and Type 3 (three bend U-return).

When do I need an internal corner instead of an external corner?

An internal corner is for inward facing angles where the building recesses. An external corner is for outward facing angles where the building projects. If the corner points away from you into a recess, it is internal.

What size Type 4 internal corner do I need?

The corner depth must match the fascia boards. Available in the same 14 sizes (150mm to 800mm).

How do you fit a Type 4 fascia internal corner?

Fix into the recess with corrosion resistant screws. Butt 2.5m fascia lengths against each side with a 3mm gap. Bond joint covers over the joints. Seal behind the corner with colour coded sealant. Engage the soffit with the reverse L-return of the corner.

Can the Type 4 internal corner be colour matched?

Yes. Powder coated in any RAL colour.

Part of a Complete Type 4 Fascia System

The internal corner is one fitting in the Type 4 fascia system:

• Type 4 Fascia 2.5m Length – parent fascia board

• Type 4 90° External Corner – outward facing corner

• Type 4 90° Internal Corner – this product

• Soffit Type 1 – soffit board and joiner

• Half Round Gutter 3m – gutter fixed to fascia

• Fascia Gutter Bracket – mounts gutter to fascia

• Colour Coded Sealant – joint sealing

• Colour Coded Fasteners – matching screws

Browse the full fascia and soffits collection. The fascia system works alongside aluminium copings, drip trims and the full rainwater goods range.

Standards and Compliance

The powder coat finish is applied in line with BS EN 12206-1 for powder organic coatings on aluminium. Powder coated aluminium fascia fittings achieve a fire classification of A2-s1,d0 under BS EN 13501-1.