Can I get a U-value calculated for my flat roofing project?
Absolutely! Please contact our freephone technical helpline on 01543 678777.
Does thicker insulation always provide better thermal performance?
Increasing insulation thickness will generally increase the thermal resistance of the insulation layer, but thickness alone does not determine the thermal performance of a complete roof.
The thermal conductivity of the insulation, the other components within the roof build-up and the construction details all contribute to the final U-value.
Different insulation materials can therefore achieve similar thermal performance at different thicknesses.
This is particularly relevant where roof build-up height is restricted, because high-performance insulation can help achieve a required thermal target without simply increasing the thickness of conventional insulation.
How is polyurethane ecological?
We do everything we can to reduce CO emissions2, but the core of our insulation products is also truly made of environmentally friendly materials.
Eco-friendly synthetic materials may seem strange to you, but with PU insulation, you will save 400 times more energy than they require for their production in 75 years. In short, a good thing for nature.
Sustainable development takes on its full meaning with Recticel Insulation polyurethane insulation:
not only does polyurethane insulation have a very high thermal performance that does not deteriorate over time, but Recticel Insulation polyurethane insulation also significantly reduces the carbon footprint of the insulation.
The proof by four:
1 - The least energy-intensive of all factory-made insulation is polyurethane insulation.
2 – Thinner and more efficient: With the same thermal performance, Recticel Insulation panels are up to 2 times thinner and 5 times lighter.
This reduces the quantities produced and so does the energy required.®
3 – Less bulky for better efficiency: This means fewer trucks to transport them.
4 – Less heavy: CO emissions2 are considerably reduced.
The ecological impact is controlled at all levels and the environment is better preserved.
We need to consume less energy:
Fossil resources such as oil are practically exhausted.
That is why we are advocating for the rational use of this oil.
In concrete terms: we need to burn less oil and use it to produce PU, the high-performance material of which our insulation materials are made.
Today, 96% of oil is used in the form of fuels.
The remaining 4% is processed into synthetic materials, of which only 0.08% is PU.
This is very unfortunate when you know that PU insulation saves 400 times more energy than it requires for its production.
The RECTICEL group acts at the international level, in all its businesses, for the protection of the environment.
How should I store Insulation boards?
Our boards are supplied in polythene shrink wrap which is designed for short-term protection only. It is accepted that storing boards indoors is not always possible – when outdoor storage is necessary, boards should be stored clear of the ground, on a level surface, and under cover to protect them from prolonged exposure to moisture or mechanical damage.
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What does “circularity” mean for Gradient’s products and processes?
Circularity means designing products and systems that minimize waste and keep materials in use for as long as possible. At Gradient, this includes responsible sourcing, efficient manufacturing, waste reduction, and developing pathways for recycling or repurposing materials at the end of their life cycle, all aligned with Recticel’s circular economy ambitions.
What does PEFC certification mean for Gradient and the Recticel Group?
PEFC certification ensures that the wood‑based materials we use come from sustainably managed forests. For Gradient, this means our sourcing practices align with strict environmental, social, and ethical standards reinforcing the Recticel Group’s commitment to responsible supply chains and traceable, sustainable raw materials.
What if I cannot provide all of the information required for thermal calculations of a specific project?
It is possible for us to make certain assumptions when performing a calculation, but this can reduce the accuracy of the final result. Assumptions are routinely made about the types of fixings to be used, but we will always try to inform you if a general figure has been used where more accurate data could affect the calculation result.
What is the best way of achieving an air and vapour barrier when using PIR insulation panels?
As per the literature supplied with the product - an effective air and vapour barrier can be achieved by the taping of board joints using suitable insulation tape, the inclusion of a separate proprietary vapour control layer or the use of a foil backed plasterboard all of these methods are acceptable forms of air/vapour control.
What is the difference between a U-value and an R-value?
U-values take into account all elements of a construction, including thermal bridges. They can only be worked out by calculation. The R-value, or thermal resistance, is a measure of the insulation board on its own, dividing the thickness (in metres) by the thermal conductivity (lambda value, W/m.K). The R-value can be used to compare how different thicknesses of products with different lambda values perform comparatively.
What is the difference between U-value, R-value and thermal conductivity?
U-value measures how easily heat passes through a building element such as a roof, wall or floor. It is expressed in W/m²K. A lower U-value generally indicates better thermal performance.
R-value represents the thermal resistance of a material or construction. A higher R-value indicates greater resistance to heat flow.
Thermal conductivity, represented by the Greek letter λ (lambda), describes how readily heat passes through a material. It is expressed in W/mK. A lower lambda value generally indicates a material with better insulating properties.
Importantly, the U-value of a roof is determined by the performance of the complete construction, not simply the lambda value of the insulation product.