Can insulation be placed between and over flat roof joists?
BS 5250:2011, the British Standard for the control of condensation in buildings, does not recommend installing insulation between timber joists as well as above the deck.
However, not all hybrid roofs will show condensation risk, our Technical Services team will be happy to assist with U-value calculations and condensation risk analysis where required, we will also discuss the potential risks involved, but please note all calculations will be marked “NOT RECOMMENDED” inline with the British Standard.
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 (see also “How to install Deck-VQ®?”).
*The thermal conductivity of the core material rises to ca. 0,020 W/mK under ambient pressure.
Do I have to follow a training course regarding the safe use of diisocyanates?
How thick do I need to insulate?
We recommend that you seek advice from your architect, designer, energy assessor etc. to determine the appropriate insulation thickness. If you already know the desired performance, you can contact our Technical Services team for U-value calculations or look up the required R-value and corresponding thickness in the technical datasheet.
The cleanest energy for heating and cooling, is the energy you do not have to use. That is why we recommend to insulate a flat roof to a higher standard than the minimum requirement. We recommend a minimum of 45 mm Deck-VQ® (Lambda (λ) = 0,009 W/mK) for renovation and 60 mm (Lambda (λ) = 0,008 W/mK) for new build.
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How to install Deck-VQ® vacuum insulation panels?
Deck-VQ® can be applied in warm flat roofs or terraces of a new build and refurbishment projects. Generally speaking the panels are installed over the existing roof covering (refurbishment) or new vapour control layer (new build). The waterproofing system is then applied on top of the insulation and finished in an appropriate manner.
The Deck-VQ® concept is a complete package, designed to limit the risk of damaging the VIP inside during installation.
To take away your concerns, we have included a couple of features and services:
NO drilling allowed? How do I fix Deck-VQ®?
- The PIR protection boards offer compatibility with a variety of adhesives and waterproofing systems*.
- The high density PIR protects the VIP inside from normal physical damage, which allows a ballasted build-up.
NO sawing allowed? How do I cover the complete surface?
- Deck-VQ® panels are available in four standard dimensions (mm x mm): 1200x600 / 1200x300 / 600x600 / 600x300 which make it possible to design an optimal configuration for your project.
- Around details (e.g. corners, edges and roof penetrations) or to fill gaps, we provide PIR insulation in the corresponding thickness.
- Our technical services can provide an optimized layout scheme (like a puzzle) as a guideline for the installation. Do not hesitate to contact us!
Example of a layout scheme:
*We recommend cold adhered single-ply systems (e.g. fleece backed PVC or fleece backed EPDM) or multi-ply bituminous systems (self-adhesive partially bonded base sheet and torch-on cap sheet). For more information on compatibility or support for you project, please contact our technical services.
***UK ONLY: Liquid applied roofing is also possible. In this case, we provide a 3 mm bituminous layer on top.
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What air gap is required between insulation and breather membrane?
This should be confirmed in the membrane manufacturer's BBA certificate, though 25mm to 50mm is typical.
What are the main tips for installing Recticel Insulation boards correctly?
- Use the right board for the application - the right type and the right format.
- Store the boards in a dry place above the ground, and use them when they are dry.
- Handle boards carefully - do not throw or kick them, be careful not to damage them.
- Ensure the intended substrate/base is clean, even, dry and smooth.
- Apply an air screen, sealing layer or damp resistant layer if necessary, particularly in flat roofs.
- Push boards together well.
- Always keep boards dry during rain showers.
- Always cover boards at the end of the working day.
- Always follow installation instructions provided.
- Always use the right attachment methods.
- Measure and cut accurately to fit using a fine toothed saw or sharp knife
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Ensure that any adhesive is compatible with the foam
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 a Vacuum Insulation Panel or VIP?
VIP is the abbreviation of Vacuum Insulation Panel. A Vacuum Insulation Panel generally comprises a microporous core material (e.g. based on fumed silica), which is introduced into a high barrier multilayer foil envelope. The envelope is then evacuated and sealed, obtaining a near vacuum inside the envelope.
Because of the microporous core and the absence of air, excellent thermal properties are obtained. For our Vacuum Insulation Panel as such (Core-VQ®) we can declare a lambda value of 0,006 W/mK, which is typically 3-5 better than traditional insulation materials.
Vacuum Insulation Panels have already been used for several decades in high demanding applications, especially when stringent requirements for thermal insulation are set (e.g. refrigerators). As the thermal insulation of buildings has become increasingly important over the last years, Vacuum Insulation Panels have been introduced in buildings to meet the high standards.
Recticel Insulation offers the following products:
What is the BBA Competent Person Scheme?
The scheme, of which Recticel Insulation is a member, is designed to ensure consistency and accuracy in the provision of U-value calculations through a process of assessment, certification and continuous monitoring. Not all insulation manufacturers are members of the scheme.