Typical Components
(1) Concrete slab
(2) 2 hour or 4 hour fire rated fire barrier compressed into expansion gap
(3) Expansion joint fitted directly over fire barrier and centred over the expansion gap
(4) Waterproofing membrane
FireFlex Overview
FireFlex Series
Fire barriers for use with expansion joints that extend through fire compartment floors
Typical Components
(1) Wall
(2) High-Temperature Refractory Ceramic Fibre
(3) Stainless Steel Foil Sheath
(4) Wall Capping
FireFlex Series
Fire barriers for use with expansion joints that extend through fire compartment walls
What this page covers
FireFlex fire barriers protect expansion joints where they pass through fire compartment floors and walls. Unlike the expansion joint itself, FireFlex is compressed directly into the gap beneath it, sealing the compartment while still allowing the joint above to move freely. As a result, a building can maintain its expansion joints without compromising fire separation between compartments. In addition, a waterproofing membrane sits alongside the barrier, so fire protection and moisture control are handled together rather than as separate systems. Meanwhile, the barrier is available in 2-hour and 4-hour fire ratings, covering most UK building regulations requirements. For projects where waterproofing is the primary concern rather than fire separation, our AquAtec overview covers that range.
How to use this page
If your expansion joint passes through a fire-rated floor or wall, FireFlex is the barrier you’ll need alongside it. Below, each product links to its own page, where you’ll find fire ratings, gap widths, and downloadable technical files. First, confirm the fire rating your compartment requires, either 2-hour or 4-hour. Then, select the FireFlex profile sized to match the expansion joint installed above it. For the lightest-duty floor joints that FireFlex is commonly paired with, see our MicrAtec overview, or browse our full product range to compare all available systems. If you’re unsure which fire rating your project needs, get in touch with our team.