Multifoil Insulation and Building Regulations

10 minute read

TLX multifoil insulation helps to insulate a building to modern standards whilst providing effective space-saving solutions. It can be used as part of a hybrid system alongside additional insulation. For a cold deck roof or wall insulation, TLX Silver provides an excellent vapour barrier, whilst also reflecting heat back into the building. Whilst a warm deck roof, TLX Gold gives all the benefits of a multifoil insulation, with the added benefit of an integrated breathable membrane.

What U-Value do I Need to Achieve to Reach Building Regulations?

Building regulations in the UK have tightened in recent years, so much so that the
current requirement for all roof types in a new build is just 0.11 W/m²K, 0.15 W/m²K for a roof extension and 0.16 W/m²K for a roof refurbishment. Therefore, it is becoming harder to achieve current standards, particularly in older buildings. Shallow, irregular rafters can be difficult to work with, especially when you need to cut the PIR board to size to fit it in place. The same is true for wall insulation. Modern insulation materials face challenges when used with older constriction methods. In the UK, the housing stock is diverse, requiring individual approaches for each project. Moreover, there is no ‘one size fits all’ solution to satisfy local building control requirements.

The Importance of Hybrid Systems

In most cases, no single insulation material can achieve the required U-Value for building regulations on its own. This is because the U-Value is a measure of how well heat is transferred through a structure, and different materials have different thermal conductivities. Therefore, many roofers are now opting for the use of a hybrid system.

To achieve the required U-Value, it is often necessary to use a hybrid system of insulation materials. This means using a combination of materials with different thermal conductivities to create a more effective barrier to heat transfer.

For example, a roof might be insulated with a layer of TLX multifoil insulation, which is a reflective material that helps to prevent heat loss. This could then be supplemented with a layer of PIR board, which is a denser material that provides additional insulation and may help to comply with regulations.

The specific combination of materials that is used will depend on the specific requirements of the building and the climate in which it is located. However, the use of a hybrid system is often the most effective way to achieve the required U-Value and comply with building regulations.

Here are some other reasons why roofers might choose to use a hybrid system:

If you are considering insulating your roof, it is important to talk to a qualified insulation installer to discuss the best options for your needs. They will be able to assess your specific requirements and recommend a system that will meet your needs and budget.

TLX multifoils can help to simplify the entire process. Whether it be a roof or a wall, an extensive renovation project or a new build development, TLX has the answers and solutions for projects of all sizes and complexities.

How Does TLX Multifoil Insulation Work?

TLX Silver is a 2-in-1 insulating vapour barrier which prevents water vapour from entering a cold space, whether it be a roof or a wall. It prevents condensation because it denies water vapour the chance of reaching a cool part of a roof or wall and condensing. Its shiny outer layers reflect heat making them very effective insulators. These layers are interspersed with layers of wadding, helping to create air layers within the material which contribute to the thermal efficiency.

TLX Silver: 

TLX Gold: 

Our TLX Gold is a 2-in-1 insulating fully breathable membrane which acts as a very effective insulator. It allows water vapour to travel through the layers and out into the environment before it has the chance to cool and condense.

How can I Achieve Building Regulations With TLX Multifoil Roof Insulation?

Our multifoils can help you to achieve current building regulations and save space
within a build-up wherever you decide to insulate.

Cold deck roof: Install TLX Silver underneath the rafters for a cold deck roof and fix it in place with 38x38mm battens. Fix additional insulation in between the rafters. You need an unventilated air space between the TLX Silver multifoil insulation and additional insulation. The reflective outer surface of TLX Silver improves the thermal efficiency of the air gap next to it. Therefore, you gain a greater performance overall.

Cold Deck Roof Solution With Breathable Membranes:

Warm deck roof: For insulation between and over rafters, TLX Gold is the perfect addition to the insulation profile. Lay TLX directly over the top of the rafter, either draped or pulled taut and counter-battened above. Leave an optimum 20mm unventilated air layer beneath it to allow for heat to reflect from its shiny breathable under surface. Plus, fit additional insulation between the rafters.

Warm Deck TLX Gold Draped Solution:

Warm Deck TLX Gold Taut Solution:

How can I Achieve wall Insulation Building Regulations With TLX Multifoil Insulation?

In all new domestic builds, the new U-Value for walls will be 0.18 W/m²K. TLX Silver can be used on the inner face of a wall, for wall insulation, just behind the plasterboard, secured in place with 38x38mm battens. Plus, set the battens crosswise to minimize thermal bridging. The addition of insulation between the studs will help to improve the thermal performance of the structure.

Brick-clad timber frame wall solution:

Are Other Types of Insulation Compatible for use Alongside TLX Silver and TLX Gold?

Yes, PIR board, mineral wool and phenolic board are all compatible. They work alongside TLX multifoil insulation to improve thermal performance. The performance depends on the core R value of the insulation you want to use. Furthermore, the better the material is at preventing heat transfer, the greater the level of insulation.

Do you Require a Bespoke Solution?

We would love to hear from you. Our helpful team of product experts are on hand to help with bespoke solutions and U-Value calculations. Simply call 01204 674 709. Also, our LABC-approved solutions guide has a wide range of pre-calculated solutions.
You can download your free copy from the footer below.