new builds

Icynene spray-foam insulation is perfect for new build applications.

Icynene is a high-performance spray applied system that not only provides outstanding levels of insulation but is quick to install also allows the building to breath naturally.

Sealed box environment.

To create a thermally efficient building, incorporating high performance insulation is essential. Traditional types of insulation – mineral wool and rigid board materials can do a good job in heat loss mitigation but they fall down in one crucial area – air leakage. This is where Icynene comes into its own. Traditional insulation can’t completely fill all voids or seal the interface between the insulation and the building structure and often struggle to cope with small structural movements which can lead to air gaps and air leakage. Up to 40 per cent of a building’s heat loss is caused by air leakage so an insulation system that works to prevent leakage – effectively creating a “sealed box” environment, is essential to minimise heat loss. Many new build schemes now aim for an air leakage score of 3, which is pretty close to a sealed box environment. Icynene spray foam insulation performs superbly here and even exceeds the stringent Passivhaus standard of air tightness.

Heating and ventilation

Icynene open cell, spray foam insulation, breathable, airtight, dual spraying - new build - roof - attic
When aiming for such stringent levels of insulation and air tightness, it’s important to choose the right heating system and with it, the right method of ventilating the building. In an air-tight building, mechanical ventilation is vital to maintain a healthy living environment. MVHR systems [Mechanical ventilation and heat recovery] are bespoke systems designed for the individual structure and installed during the build programme. They extract moist, stale air from “warm rooms” – the kitchen & bathrooms, then pass it through a heat exchanger and gently return fresh, warmed air back into the living space. We can guide you on the best way to incorporate MVHR systems. Renewable energy sources – air-sourced and ground-sourced heat pumps are the environmentally friendly way forward and are another crucial element in achieving high efficiency/low running costs. They work like a fridge in reverse, taking latent heat out of the air or ground and use it to drive underfloor heating systems and serve domestic hot water requirements. Again, we can guide you on how best to combine these important elements.


Spray applied foams such as Icynene are open cell materials which provide outstanding insulation performance but also allows the building to breath naturally, resisting internal condensation – particularly important when insulating heritage-type buildings and creating sealed box, new build structures either of masonry or timber frame construction.

Speed of Install

Icynene open cell spray foam insulation - cut back on walls application - new build

Icynene spray foam insulation is fast, efficient and cost effective. JSJ has multiple spray rigs. At present, one of our vehicles has a 2-gun system installed. This system allows for dual spraying from one rig. We are the only contractor within the spray foam market in Europe to have this piece of equipment. On a new build project, where access is good, we have the potential to spray between 400m2 – 600m2 in one day. We are currently working towards converting another vehicle to dual spraying as well.

Free advice and guidance

JSJ has many years of construction experience, we would love you to take advantage of this knowledge? We can help with U-Values and condensation risk analysis for your project and provide a host of related, down to earth guidance (ask us about distance screws) that could save you on overall build costs.
We can show you how to achieve the best combination of high-performance insulation and guide you through the intricacies of air or ground-sourced heating and mechanical ventilation and heat recovery systems.
Talk to JSJ, we’re here to help!

Distance screws for horizontal battening using Icynene Spary Foam Insulation
Distance screw for wood