Super-slim Deck-VQ® panels from Recticel Insulation ensure roof terraces seal the thermal envelope

In association with


Previously considered as somewhat of a luxury, roof terracing is finding prevalence in new-build and refurbishment projects, as householders and builders look to maximise increasingly precious living space within evermore dense housing developments. Due to height restrictions caused by window and door thresholds, insulating roof terraces in order to achieve regulatory thermal performance presents a challenge. Chris Knowles, Business Manager (Vacuum Insulation Panels) at Recticel Insulation, one of the world’s leading PIR manufacturers, looks at how these challenges can be overcome by offering a guide to roof terrace insulation, as well as highlighting the benefits of a slimline panel that has been specifically created to achieve an excellent thermal performance in building projects where space and height are issues.


With suitable plots at a premium, an increasing number of property developments are being built with outdoor space in order to optimise available land. As such, keeping thresholds low through innovation of ultra-thin insulation and waterproofing design is a growing challenge. The following guide provides some useful tips on dealing with issues relating to roof terrace design, which can be overcome with VIPs vacuum insulation panels: a super-slim solution which provides maximum performance but at a much reduced product thickness, thus helping to overcome threshold issues.

  1. Prevention is better than cure, a saying that is particular pertinent to house building and renovation. In the case of roof terrace insulation, it means providing answers for some initial key questions, such as how can specified U-values be achieved whilst working within insulation height restrictions? This is where standard PIR products fall short in terms of terrace installation performance, as it generally means either compromising on U-value outcomes or compromising on drainage by installing channels or raising the low thresholds. VIP solutions are ideal for terraces and flat roofs as they deliver a high thermal performance without the need for structural alterations. Working with a specialist roofing design team such as Recticel’s tapered roof insulation division, Gradient, will ensure the specified VIPs meet a project’s design, optimising performance, materials and cost.
  2. Conduct a site survey. In many instances, the initial take-off drawing/specification of a project will differ from what is the ‘reality’ on-site. Therefore, it is always recommended to have a site survey carried out prior to ordering a VIP solution. Given that VIPs cannot be cut or altered on site, it is vital that dimensions are correct prior to order. This should also take into account potential obstructions or openings such as rooflight and drainage outlets, which would affect the layout of a vacuum insulation panel scheme.
  3. Use a protected VIP, as vacuum insulation panels are vulnerable to puncture. If this happens the VIP’s insulation value will degrade to that of a conventional PIR material. A construction site could therefore pose problems for VIPs during their handling and installation. The best solution is to utilise a product such as Recticel’s Deck-VQ, as the VIP is fully-encapsulated within a high density PIR protective shell. This provides reassurance that the insulation can be easily installed by the contractor, with the knowledge that the VIP’s excellent thermal insulation value will be maintained.
  4. Ensure the contractor is aware of the insulation technology being used in a roof terrace scheme, particularly in relation to VIPs. They need to be aware that VIPs cannot be cut or modified on-site, which is a complete shift of mind-set from when they use conventional insulation products.
  5. Always use the design layout provided. By working with Gradient, a full project design package is supplied. This provides a scheme layout in conjunction with the product delivery and ensure the quantity of material delivered is optimised to eliminate or reduce site waste. It is therefore vital that the design scheme is followed exactly, in order to avoid installation difficulties and product shortfall.

The aforementioned VIP solution Deck-VQ® has been specifically developed by Recticel to deliver high thermal performance for applications such as terraces where insulation build-up thickness is an issue. Its superior thermal credentials – it has a lambda value of the core of 0.006 W/mK – come to the fore in enabling even the most complex terrace projects to be carried out without the need for structural changes, thus reducing on-site working times and and materials.


Roof terraces have practical purpose, as well as add to a building’s feel-good factor. Their thermal performance is every bit as crucial to a property’s overall energy output. Therefore, the availability of Deck-VQ®, which simplifies the insulating of such spaces to excellent effect, will ensure this modern design feature doesn’t detrimentally impact a building’s sustainable wellbeing.

Contact Details
For more information, please visit the Recticel Insulation website.