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 I get a U-value calculated for my flat roofing project?
Absolutely! Please contact our freephone technical helpline on 01543 678777.
Can I walk on Deck-VQ® vacuum insulation panels?
Yes, this is possible due to the protection layers in high density PIR and the compressive strength of 150 kPa (CS(10\Y)150). Deck-VQ® is suitable for application in flat roofs and terraces, subject to light foot traffic.
As for every type of insulation, we recommend to limit the foot traffic during installation to a minimum and apply the waterproofing as soon as possible after installation. It is best practice to only install the area you are able to insulate AND waterproof in one day.
Can you drill, nail or saw into a Vacuum Insulation Panel?
No, because these actions will lead to the loss of vacuum in the VIP and reduce the thermal performance by a factor of three*.
Our Deck-VQ® concept offers an optimum protection to prevent most damage on site. (see “What is the difference between Deck-VQ® and a Vacuum Insulation Panel?”).
Our technical services provide guidance and deliver a detailed design for your project.
Do not hesitate to contact us for further information.
*The thermal conductivity of the core material rises to ca. 0,020 W/mK under ambient pressure.
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.
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 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
-
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.
What happens if a vacuum insulation panel is damaged?
Damage that penetrates the vacuum insulation panel can cause the vacuum to be lost, reducing its thermal performance.
For this reason, vacuum insulation panels should not be drilled, nailed or sawn.
Gradient specifically states that drilling, nailing or sawing a Vacuum Insulation Panel can cause loss of vacuum and reduce thermal performance. Deck-VQ® incorporates protective high-density PIR layers designed to provide additional protection to the vacuum panel during installation and use.
Installers should follow the manufacturer's installation instructions and avoid activities that could damage the panels.
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.