FAQs - Frequently asked questions

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.

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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.

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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.

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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
  • Upstands and perimeter details

Gradient provides a design service that produces a pre-designed, dimensionally accurate tapered insulation solution with detailed layout drawings.

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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.

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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:

  • Core-VQ®: the ‘naked’ VIP and the heart of our vacuum insulation solutions that can be incorporated in a variety of systems (e.g. VIP inside Deck-VQ®)

  • Deck-VQ®: a premium solution, developed for flat roofs and terraces, where the VIP is protected by a high density PIR on all sides.

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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.

What is tapered insulation?

Tapered insulation is insulation manufactured or designed with varying thicknesses to create a fall across a flat or low-slope roof.

Rather than using insulation of a constant thickness, a tapered scheme uses different insulation thicknesses to form designed falls that direct rainwater towards outlets, gutters or other drainage points.

Gradient provides bespoke tapered insulation solutions designed around the individual roof geometry, including new and existing roofs.

Take a look at our tapered solutions

What is vacuum insulation and how does it work?

Vacuum insulation panels, or VIPs, are high-performance insulation panels designed to provide a high level of thermal resistance within a relatively small thickness.

Gradient's VIP technology uses a core based on pyrogenic silica enclosed within a gas-tight multilayer film. The panel is then protected within a high-density, pressure-resistant PIR casing in the Deck-VQ® system.

The vacuum and core structure significantly reduce heat transfer through the insulation, allowing very high thermal performance from a relatively thin panel.

Vacuum insulation is particularly useful where there is insufficient space to accommodate the thickness of conventional insulation.

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