Can a flat roof survey tell me if my insulation is adequate?
Not necessarily. A visual survey may identify information about the apparent roof build-up, but it cannot reliably confirm the condition, moisture content or thickness of concealed insulation. Where this information is required, further investigation such as core sampling may be necessary. The applicable thermal requirements also depend on factors including the building, the work being undertaken and which Building Regulations provisions apply.
Can tapered insulation be used on an existing flat roof?
Yes. Tapered insulation can be designed for both new and existing roofs.
For refurbishment projects, the existing roof construction should be assessed before a tapered insulation scheme is designed. The survey and design should consider the existing roof dimensions, drainage points, falls, obstructions, roof condition and the proposed new roof build-up.
Do I need an intrusive survey or core samples?
Not every roof survey requires intrusive investigation. If the purpose is to identify visible defects or drainage issues, a visual assessment may be sufficient. However, where the condition of the underlying roof build-up, moisture levels or insulation needs to be established, intrusive investigation may be recommended. The appropriate scope will depend on the condition of the roof and the reason for the survey.
How can I improve the thermal performance of an existing flat roof?
Improving an existing flat roof's thermal performance may involve adding insulation as part of a refurbishment or overlay system, subject to the condition and construction of the existing roof.
The appropriate solution depends on factors such as:
- Existing roof construction
- Existing waterproofing
- Available build-up height
- Required U-value
- Moisture and condensation considerations
- Drainage
- Existing roof condition
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Upstands and junctions
Where available space is restricted, high-performance insulation such as vacuum insulation can provide an option for achieving improved thermal performance without requiring the same thickness as some conventional insulation products. Gradient's Deck-VQ® has been used in refurbishment projects where existing roof height and parapet constraints limited the available build-up.
How do I prevent thermal bridging through a flat roof?
Thermal bridging occurs where heat can flow more readily through part of a building element because of a change in material, geometry or construction.
In a flat roof, thermal bridging can occur around areas such as junctions, penetrations, parapets, rooflights and structural elements.
Good design should aim to maintain continuity of insulation wherever possible and address junctions and details appropriately.
The thermal performance of the complete roof build-up should be assessed rather than considering the insulation product in isolation. Accurate U-value calculations can help determine the thermal performance of the proposed construction. Gradient states that its U-value calculations are based on the relevant calculation methodology, including BS EN ISO 6946 for building elements.
How is a tapered insulation scheme designed?
A tapered insulation scheme is designed around the geometry and drainage requirements of the individual roof.
The design process should consider factors such as:
- Roof dimensions and geometry
- Drainage outlets and gutters
- Existing falls and backfalls
- Rooflights and other obstructions
- Required insulation performance
- The structural deck
- Waterproofing system
- Required roof build-up
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Upstands and perimeter details
Gradient provides a design service that produces a pre-designed, dimensionally accurate tapered insulation solution with detailed layout drawings.
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.
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 is a warm flat roof construction?
A warm flat roof is a roof construction where the insulation is positioned above the structural roof deck, keeping the deck and structure on the warm side of the insulation.
A typical warm roof build-up may include the structural deck, vapour control layer, insulation and waterproofing system. The exact arrangement depends on the roof construction and waterproofing system being used. Warm roof construction can provide continuous insulation across the roof, helping to reduce heat loss and improve the thermal performance of the building. The complete roof build-up should be designed to meet the required thermal, moisture, structural and fire performance criteria.