Why Use Enverge Nexseal LE Closed Cell For Concrete Soffits

As a part of our series on use cases for spray foam insulation, we look at the use case of Enverge Nexseal LE Closed Cell when applied directly to a flat, waffle or ribbed concrete soffit. Concrete soffits are prevalent in many commercial and residential buildings throughout the UK. From cold underground car parks with heated spaces above to basements and swimming pools, many types of concrete soffits may require insulation to modern standards to help reduce heat loss, surface humidity and thermal bridging.

Enverge Nexseal LE Closed Cell for concrete soffits can offer several benefits over pre-manufactured and mechanically fixed insulation materials. Irregular or curved soffits such as waffles or ribbed decks are often difficult to cut, fit and fix pre-manufactured insulation materials into place. This time-consuming process may delay and disrupt a project beyond acceptable levels, whilst off-cuts of expensive materials are often left unused and thrown away. Additionally, pre-manufactured materials require mechanical fixings, which could be subject to movement or failure over time, reducing the effectiveness of the insulation and leading to thermal transfer, which could cause condensation build-up.

Spray-applied as a liquid that adheres to the substrate and then expands to its final, cured state, Enverge Nexseal LE Closed Cell has excellent mechanical resistance of 78 KPA and dimensional stability of less than a 2% change. Additionally, the thermal conductivity of 0.027 W.m.K helps to make closed-cell spray foam one of the most thermally effective insulation materials per inch. Spray-applied up to 100mm per layer, Enverge Nexseal LE is one of the safest closed-cell foams available, and the low exothermic reaction will help eliminate the risk of delamination and warping due to applicator error. A contemporary material for the modern, eco-conscious world, Enverge Nexseal LE contains almost 10% renewable content and can add LEED points to any constriction project to reflect its sustainability.

With more demanding requirements on fire ratings of insulation lining materials, spray foam insulation on its own is classed as a not non-combustible system and, therefore, may expect to achieve a Euroclass E or F fire rating. However, modern spray foam products form part of a system that combines the insulation application with a protective intumescent coating to achieve a Euroclass B rating. Therefore, whilst deemed potentially unsuitable and often overlooked, it is usually possible to implement Enverge Nexseal LE Closed Cell into concrete soffit specifications when used with a protective coating.

Suppose you are an architect considering specifying Enverge Nexseal LE Closed Cell Insulation. In that case, we are listed on NBS Source under ThermoFoam or by clicking here: https://rb.gy/xbd076 – alternatively, for more information, our technical team are available on 01208 832602. They can assist with any specification or enquiry. For construction professionals, specifiers and project managers undertaking a project, Enverge Nexseal LE Closed Cell could help to keep your project on a critical path, meeting deadlines and cost management whilst reducing resources to fit pre-manufactured materials.

So How Is Nexseal LE Safer?

Unlike many other brands of closed cell spray foam insulation, Nexseal LE can be applied in layers of up to 100mm. This helps to provide the end user with reassurance that the foam will not crack, shrink, char or combust, especially if it’s being covered over with plasterboard. For the installer, the job can be completed faster without the need for many different layers of foam and this can also benefit the project itself by speeding up the installation process. The low exothermic reaction helps to release any heat from the foam quickly during the expansion process and vastly reduces the opportunity for heat to be trapped within the layers. Although professional spray foam installers will follow manufacturers guidance to ensure that any brand of foam is installed correctly, Nexseal LE is simply a more forgiving and safer foam when pushed to the limits.

Check out our video below to show how Nexseal LE is sprayed thickly and quickly with a smooth, even rise to provide a safe, monolithic and airtight thermal layer of closed cell insulation.


In conclusion, whether you are the end user of spray foam insulation or the installer, you want to work with materials that provide the best end result. For end users, Nexseal LE is the safer choice thanks to the low exothermic reaction of the product during the installation process. This ensures that the risks of the closed cell foam cracking, shrinking, charring or combusting is extremely low when compared with some other brands of spray foam insulation. For the installer, Nexseal LE can be installed quickly and efficiency thanks to its ability to be sprayed at up to 100mm per layer. Where many other brands of closed cell foam are limited to 25-50mm per layer, Nexseal LE enables the installer to confidently apply the foam in thicker layers to achieve the desired outcome in less time. Many spray foam installers are converting to Nexseal LE for peace of mind and better outcomes for their customers. 

Despite what some people may say, there are distinct differences between the performance of spray foams depending on who they are manufactured by and where in the world they are manufactured. Nexseal LE is priced accordingly thanks to its high yield per set, ease of install and ultimate safety for the installer and end user.

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