Box Gutter Expansion Joint 225 mm × 1 m – Grey EPDM

The Box Gutter Expansion Joint is a premium linear flashing solution designed to accommodate thermal expansion and contraction in continuous box gutter runs. Crafted from 225 mm‑wide, grey EPDM rubber with encapsulated metal springs, it ensures a flexible, durable seal while protecting roof integrity.

Product Features & Variations

Feature	Specification
Width	225 mm
Length	1 m (also available in 3 m and 10 m)
Material	Ozone-resistant grey EPDM rubber, 1.4 mm thick
Metal Edges	0.8 mm aluminium flanges for secure fixing
Internal Mechanism	Flexible, expandable EPDM encapsulating metal spring sides
Temperature Resistance	Rated up to 135 °C intermittently
Warranty	Manufacturer-backed longevity typically 20–25 years

Why It’s Essential

Thermal movement mitigation: Prevents damage by allowing box gutter runs to expand and contract safely.
Secure sealing: Aluminium edges are fastened with screws or rivets, and filled with suitable silicone for watertight protection.
Durable construction: EPDM resists ozone and UV, while the metal spring mechanism ensures flexible performance for many years.
Simple installation: Cut to length, centre over gutter joints, secure through aluminium flanges and seal edges.

Available Variants

The product is also stocked in:

3 m and 10 m lengths – for longer gutter runs
Other widths – such as 280 mm wide versions for larger systems

Typical Applications

Long-span box gutters that require accommodation for expansion and contraction
Flashing junctions at parapets, stepped flashings, skylight gutters or roof transitions
Sealing square ducts and penetrations where movement is expected

Installation Summary

Measure and cut required length across gutter joint.
Centre expansion joint over the seam.
Secure aluminium edges using self-drilling screws or sealed rivets.
Seal perimeter with high-quality roof‑and‑gutter silicone.
Expansion joint flexes with thermal movement; maintain edges every 40–50 ft (12–15 m)

The Box Gutter Expansion Joint 225 mm × 1 m Grey combines reliability, flexibility, and clean installation to protect long-run gutters from damage caused by thermal stress. With its EPDM durability, aluminium securing flanges, and expandable core, it’s an essential component for tradespeople and roofers seeking a long-lasting, code-compliant solution in box gutter systems.