N2

N2 is a hot pour surface sealant compliant with BS EN 14188-1, classified as the normal, low-extension type. It is closely related to N1 but designed for joints with more modest movement, making it a sound, cost-effective choice for stable surface joints where the high extension of N1 is not required. In our experience, N2 works better than N1 on low-movement joints because its firmer characteristics resist stone and dirt pickup without the cost of an elastic sealant.

Slots must be dry, sound, clean and free from frost and dust before sealing, with the finished seal recessed below the surface to prevent extrusion under traffic in hot weather. Where a joint sees significant thermal expansion and contraction, N1 is the better specification.

Applications: Stable, low-movement surface joints on highways and airfield surfaces. Specification: N2 hot applied joint sealant.

A mistake that turns up on sealant schedules is treating N2 as fuel resistant. Under BS EN 14188-1 fuel resistance belongs to the F grades, F1 and F2, and N2 is not tested against fuel for its classification. Where a joint will see aviation fuel, diesel or hydraulic fluid, the right answer is an F grade or a cold applied fuel-resistant system such as Thioflex 555.

Where it is the right grade, N2 is quick to work with. It cures by cooling rather than by chemical reaction, so a sealed joint is usually trafficable within 30 to 60 minutes depending on the weather and the depth of the pour. That fast return to service is why hot applied grades are standard on highway and airfield closures.

The full comparison is in what's the difference between N1 and N2 sealant? and what is N2 sealant?