C4 Universal Internal Corner

The C4 Universal Internal Corner Trim is a pre-formed GRP (Glass Reinforced Plastic) corner piece designed to deliver a clean, watertight, and professional finish on fibreglass flat roofs. This versatile trim fits seamlessly with both A and B trim profiles, making it suitable for left and right internal corners — eliminating the need for mitre cuts on site.

Crafted from premium-grade fibreglass, the C4 trim provides excellent durability, resistance to weathering, and long-term performance, ensuring your GRP roofing installation remains protected and looking professional for years to come.

Key Features

1. Universal Design: Suitable for both left and right internal corners.
2. Compatible with A & B Trims: Perfect match for A200 Drip Trim and B260 Raised Edge Trim profiles.
3. Pre-Formed GRP Construction: Made from high-quality glass-reinforced plastic for superior strength.
4. Watertight Seal: Prevents leaks and ensures a strong, durable connection at internal corners.
5. Quick Installation: No need for mitre cuts—simply bond, nail, and bandage for a secure fit.
6. Professional Finish: Delivers a smooth and neat appearance across all roof edges.

Directions for Use

1. Position the C4 Internal Corner Trim at the internal roof junction.
2. Secure it to the deck with nails — one at each end and one in the middle.
3. Apply a thin bead of PU trim adhesive between the trim and the corner.
4. Smooth the adhesive using a wetted instrument or finger to seal the entire joint.
5. Bandage over the joint for added strength and waterproof protection.

Why Choose the C4 Universal Internal Corner Trim?

The C4 Universal Internal Corner Trim simplifies the installation of GRP roofing systems by removing the need for complex mitre cutting. Its universal design fits both sides of internal corners, providing flexibility and precision. Whether you’re a professional installer or DIY roofer, this trim ensures a clean, watertight, and long-lasting finish every time.

Ideal for use on:

1. GRP flat roofs
2. Garage and extension roofs
3. Roof edges and parapets
4. Walkways and balconies

Here are 5 more great reasons to buy from us:

Returns are easy, if the items are�unopened and unused�then simply�contact us�for a returns number and send your item to our returns centre for fast processing. We'll get you a replacement or refund in a snap!

In the unlikely event that you find your item cheaper at another online store, just let us know and we'll beat the competitor's pricing hands-down.

We insist that you love everything you buy from us. If you're unhappy for any reason whatsoever, just let us know and we'll bend over backwards to make things right again.

Ordering from APEX Fibreglass Roofing Supplies is 100% safe and secureso you can rest easy. Your personal details are never shared, sold or rented to anyone either.

Here are 5 more great reasons to buy from us:

Returns are easy, if the items are�unopened and unused�then simply�contact us�for a returns number and send your item to our returns centre for fast processing. We'll get you a replacement or refund in a snap!

In the unlikely event that you find your item cheaper at another online store, just let us know and we'll beat the competitor's pricing hands-down.

We insist that you love everything you buy from us. If you're unhappy for any reason whatsoever, just let us know and we'll bend over backwards to make things right again.

Ordering from APEX Fibreglass Roofing Supplies is 100% safe and secureso you can rest easy. Your personal details are never shared, sold or rented to anyone either.