Over & Under Rafters (Internal & External) Solutions

INSULATING A PITCHED ROOF OVER AND UNDER RAFTERS.

Insulating a pitched roof over, between and below the rafters is the common method chosen for re-roofing existing buildings, extensions and new builds as it provides superior thermal performance for the building. Insulating the roof above and below the rafters is known as warm roof insulation as the rafters are brought into the insulated envelope of the building.

This over and under rafter insulation method also reduces thermal bridging, giving an airtight continuous layer of high-performance insulation and results in a well-insulated attic space.

Insulating your pitched roof can be an expensive job, so selecting the right solution is important.

Here at YBS insulation we have specifically designed products that offer high thermal performance, whilst meeting specific performance requirements such as breathability, vapour control, etc,

Insulating externally and internally is a quick and easy way to achieve high thermal values that meet building regulations.

The recommended roof insulation for this method of warm roof construction are shown below.

3 & 4 layer insulation solution

Our tried and tested 3 layer solution is all you need for your pitched roof refurbishment, loft conversion or extension project.

This quick and easy solution will allow your roof to breath, reduce condensation, while insulating to a high level, meeting building regulations target u-value of 0.18.

BreatherQuilt removes the need for a separate breather membrane as it built into the product.

The low vapour resistance of BreatherQuilt allows the rafters to breath and its W1 rating keeps the external elements out.

Recessing a layer of SuperQuilt between the rafters and a layer of SuperQuilt internally removes the need for a vapour control layer, increases the overall thermal efficiency of the pitched roof and increases the internal space available due to its ultra-thin profile.

Using SuperQuilt can significantly reduce the overall impact to head height, when compared to traditional insulation solution, saving you valuable money, time and space.

Need to meet new build regulations?

Try our 4 layer solution, offering the same great benefits but with higher thermal performance.

Once SuperQuilt has been taped and sealed on all overlaps and perimeter, it also works as a high performing VCL (vapour control layer).

BreatherQuilt (draped) & SuperQuilt 3 & 4 Layer Insulation Solution

Description (rafters at 400mm centres)U-Value
BreatherQuilt (Draped), SuperQuilt (recessed under rafters), SuperQuilt (under rafters)0.18
BreatherQuilt (Draped), SuperQuilt (recessed under rafters), SuperQuilt (under rafters), SuperQuilt (under rafters)0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)
Description (rafters at 600mm centres)U-Value
BreatherQuilt (Draped), SuperQuilt (recessed under rafters), SuperQuilt (under rafters)0.18
BreatherQuilt (Draped), SuperQuilt (recessed under rafters), SuperQuilt (under rafters), SuperQuilt (under rafters)0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)

BreatherQuilt (taut) & SuperQuilt 3 & 4 Layer Insulation Solution

Description (rafters at 400mm centres)U-Value
BreatherQuilt (Taut), SuperQuilt (recessed under rafters), SuperQuilt (under rafters)0.18
BreatherQuilt (Taut), SuperQuilt (recessed under rafters), SuperQuilt (under rafters), SuperQuilt (under rafters)0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)
Description (rafters at 600mm centres)U-Value
BreatherQuilt (Taut), SuperQuilt (recessed under rafters), SuperQuilt (under rafters)0.18
BreatherQuilt (Taut), SuperQuilt (recessed under rafters), SuperQuilt (under rafters), SuperQuilt (under rafters)0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)

For optimal visual performance, use the highest available quality, click the Cog icon

2 layer insulation solution

Our 2-layer solution offers a great option for pitched roof refurbishments, loft conversion, extensions, or new build projects where there is access to the external and internal of the roof.

Using BreatherQuilt (draped or taut installation detail) externally removes the need for a separate breather membrane as it is built into the product, it also keeps the overall roof profile height down to a minimum.

Traditional insulation like PIR or Mineral Wool can be installed been the rafters.

Installing a layer of SuperQuilt internally removes the need for a vapour control layer, increases the overall thermal efficiency of the pitched roof and increases the internal space available due to its ultra-thin profile.

Using SuperQuilt can significantly reduce the overall impact to head height, when compared to traditional insulation solution, saving you valuable money, time and space.

This quick and easy solution will allow your roof to breath, reduce condensation, while insulating to a high level.

Once SuperQuilt has been taped and sealed on all overlaps and perimeter, it also works as a high performing VCL (vapour control layer).

BreatherQuilt, SuperQuilt & Traditional Insulation Between Rafters Insulation Solution

Description (rafters at 400mm centres)U-Value
BreatherQuilt (Draped) & SuperQuilt 0.27
BreatherQuilt (Draped), 40mm PIR (0.022 W/mk) & SuperQuilt 0.18
BreatherQuilt (Draped), 60mm Mineral Wool (0.035W/mk) & SuperQuilt0.18
BreatherQuilt (Draped), 110mm PIR (0.022 W/mk) & SuperQuilt 0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)
Description (rafters at 600mm centres)U-Value
BreatherQuilt (Draped) & SuperQuilt 0.27
BreatherQuilt (Draped), 35mm PIR (0.022 W/mk) & SuperQuilt 0.18
BreatherQuilt (Draped), 50mm Mineral Wool (0.032W/mk) & SuperQuilt0.18
BreatherQuilt (Draped), 100mm PIR (0.022 W/mk) & SuperQuilt 0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)

BreatherQuilt, SuperQuilt & Traditional Insulation Between Rafters Insulation Solution

Description (rafters at 400mm centres)U-Value
BreatherQuilt (Taut) & SuperQuilt 0.26
BreatherQuilt (Taut) , 40mm PIR (0.022 W/mk) & SuperQuilt 0.18
BreatherQuilt (Draped), 60mm Mineral Wool (0.035W/mk) & SuperQuilt0.18
BreatherQuilt (Taut) , 110mm PIR (0.022 W/mk) & SuperQuilt 0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)
Description (rafters at 600mm centres)U-Value
BreatherQuilt (Taut) & SuperQuilt 0.26
BreatherQuilt (Taut) , 40mm PIR (0.022 W/mk) & SuperQuilt 0.18
BreatherQuilt (Draped), 50mm Mineral Wool (0.032W/mk) & SuperQuilt0.18
BreatherQuilt (Taut) , 100mm PIR (0.022 W/mk) & SuperQuilt 0.13
In accordance with BDA Kiwa Agrèment certification(W/m²K)

Product Guides

YBS SuperQuilt

YBS BreatherQuilt

All Resources

Tips and Advice

Certification

YBS Insulation products are manufactured to the highest quality and certified to industry standards.

YBS Insulation Product Information

Product - BreatherQuilt - See more

YBS BreatherQuilt is a high performing Agrément Certified insulating multi-foil offering both thermal properties, along with a highly effective breathable membrane which is both water resistant and vapour permeable.

Designed to replace the need for a stand alone breather membrane, whilst offering a high level of thermal performance, the unique layer composition of BreatherQuilt effectively deals with condensation and all forms of energy transfer. Flexible and easy to install this high quality insulation provides a sustainable approach to thermal and breathable insulation. Suitable for use in pitched roofs, BreatherQuilt now includes a built in double-sided tape for ease of installation.

This product is suitable for pitched roofs and offers the following major benefits –

  • Dual purpose 2-in-1 insulating and breathable roofing membrane
  • Removes the risk of condensation
  • Effectively reflects heat back into the room, whilst allowing moisture to pass through
  • Low vapour resistant breather membrane (LR)
  • Waterproof outer membrane with Class W1, can be left exposed for up to four weeks
  • Zero fibres removes the need for PPE
  • Unique overlapping method, totally removes the risk of thermal bridging
  • Now includes built-in easy peel double sided tape for ease of installation

BreatherQuilt has been independently tested and certified to the latest Industry Standards, including BDA Kiwa certificate of Agrément and is accepted by NHBC.

Product - SuperQuilt - See more

SuperQuilt is one of the UK’s leading multifoil insulations. This flexible, easy to install, multilayer insulation offers tremendous thermal benefits. The benefit of multifoil insulation is that it is suitable for a range of applications from roof insulation, floor insulation and wall insulation and due to the slim depth, you can save valuable space on your installation. The unique composition of the product effectively deals with all forms of energy transfer.

This product is suitable for roofs, walls, floors and offers the following major benefits –

  • Cost saving Solution
  • Effective 2 in 1 insulation and vapour control membrane
  • Reduces Construction Depth
  • Reduces Risk of Condensation
  • Non degradable maintaining thermal performance and product integrity

SuperQuilt has been independently tested and certified to the latest Industry Standards, including BDA Kiwa certificate of Agrément, Building Control Compliance (LABC registered detail) and NHBC Acceptance.

Virtual Assistant