How to achieve 0.15 U-value – Pitched Roofs

We understand that achieving U-values for building control can be difficult when you are up against head-height restraints, alongside constant rising costs on materials.

Here we will advise what products you can use to achieve 0.15 U value in Pitched Roofs.

Systems to hit 0.15 U-value, supplied by Multifoils Direct

How to achieve 0.15 – Pitched Roof U-value

What is a U-value?

A U-value is a measurement of heat loss, and can explain the energy efficiency of an area, e.g. Roof, Wall, Floor, Windows. The U-value is calculated by a sum of all the thermal resistances layers that makes up the structure. For example, in a roof, you would generally find tiles, membranes, airgaps and timber so all these factors can impact the U-value in either a positive or negative way.

The lower the U-value, the less heat will escape from that area. If you are renovating, or building a dwelling, it is essential to ensure the building is achieving the respected U-values. In addition, due to rising energy costs, lower U-values will result in lower energy bills.

Building Regulations for U-values in 2024

Approved Document Part L has been updated in relation to U-values, heat gain and heat loss. The new rules came into play in June 2022. More information on Part L can be found at the following link on the UK government website – See Data Source.

New since 2023 – U-value requirements for existing dwellings
Application	Current U-value
Roof (Pitched & Flat Roof)	0.15
Wall	0.18
Floor	0.18

What does this mean for my project?

In a nutshell, the lower the U-value requirement, the more insulation is required for your project.

Recommended Products

Multifoils Direct are the leading distributor of both SuperQuilt and BreatherQuilt. Both these product are multi-layered blankets consisting of reflective foils, PE foams and recycled waddings. These products are proven space-savers, due to their slim profiles alongside excellent R-value ratings. In the recommended systems below, you will find details including SuperQuilt and BreatherQuilt, also SuperQuilt with additional insulation materials.

SuperQuilt For Pitched Roofs

SuperQuilt – Product Link – Click Here!
40mm multifoil with 19 layers
Compressed to just 7mm
BDA & BBA Agremont Certified
Built-in Vapour Control Layer
UK Manufactured
Made of 83% Recycled Materials

YBS SuperQuilt to achieve 0.15

BreatherQuilt For Pitched Roofs

BreatherQuilt – Product Link – Click Here!
11 Layer Multifoil
40mm thickness, 7mm compressed
BDA Agremont Certified
3-in-1, Waterproof, Breathable and Insulating
UK Manufactured
Made of 72% Recycled Materials

BreatherQuilt for Pitched Roofs

Systems to achieve 0.15

Multifoils Direct have a variety of methods and systems to achieve current U-value regulations, for pitched roof projects. The details below vary, depending on if you are insulating under the rafter, over the rafter, or a combination of both. You will also find the minimum rafter depth required for the project in the comments under each image.

Option A – 3 Layers SuperQuilt, Standard Plasterboard – Insulating Under Rafter

Option A – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 100mm @ 400mm Centres

Product Link: SuperQuilt Three Layer 0.15 Roof System | Loft Roof Insulation (multifoilsdirect.co.uk)

Option B – 2 Layers SuperQuilt, 52.5mm Insulated Plasterboard – Insulating Under Rafter

Option B – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 100mm @ 400mm Centres

Option C – 1 Layer SuperQuilt, 110mm PIR Insulation, Standard Plasterboard – Insulating Under Rafter

Option C – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 160mm @ 400mm Centres.

Option D – 1 Layer SuperQuilt, 100mm Phenolic Insulation, Standard Plasterboard – Insulating Under Rafter

Option D – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 150mm @ 400mm Centres.

Option E – 2 Layers SuperQuilt, 100mm Non Itch, Standard Plasterboard – Insulating Under Rafter

Option E – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 125mm, at 600mm centres.

Product Link: TrioQuilt 0.15 Roof Insulation System • Multifoils Direct

Option F – 2 Layers SuperQuilt, 50mm PIR Insulation, Standard Plasterboard – Insulating Under Rafter

Option F – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 100mm, at 600mm centres.

Option G – 1 Layer SuperQuilt, 70mm PIR Insulation, 1 Layer BreatherQuilt, Standard Plasterboard – Insulating Over & Under Rafter

Option G – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 125mm, at 400mm centres.

Option H – 1 Layer SuperQuilt, 140mm Rockwool, 1 Layer BreatherQuilt, Standard Plasterboard – Insulating Over & Under Rafter

Option H – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 100mm, at 600mm centres.

Option I – 1 Layer SuperQuilt, 75mm PIR Insulation, 1 Layer BreatherQuilt, Standard Plasterboard – Insulating Over Rafter Only

Option I – Method to achieve 0.15 on a pitched roof. Minimum rafter depth 100mm, at 600mm centres.

Require a certificate for building control?

If you’re going through building control, it is likely they will want to see a document displaying the achieved U-value. These can be downloaded from our Online U-Value Calculator. Once the form is filled, our system will email the bespoke calculation in PDF form. This can be sent over, or printed off for your building control officer.

Struggling to find the correct calculation? If so, please request a U-value on our Contact Form! Mention the above option (e.g. Option C, or Option D) alongside the m² coverage, we will email a bespoke U-value Calculation and quote.

If you require a solution slightly different, we can also assist – Please email sales@multifoilsdirect.co.uk

Delivery Schedule

Multifoil’s Direct offer SuperQuilt and BreatherQuilt with next-working day delivery!

You can purchase these as loose rolls, or save cost with our Trade Pallet Deals!

See below links to order both online with next-working day delivery;

SuperQuilt Loose Rolls – Click Here!
SuperQuilt Trade Pallet – Click Here!
BreatherQuilt Loose Rolls – Click Here!
BreatherQuilt Trade Pallet – Click Here!

Disclaimer

All build-ups and suggestions are provided in good faith. Our recommend details should be double checked with building control before committing to a purchase. The U-value table is a guide, and your desired target U-value is to be advised from your building inspector. Please check the calculations for correct air-gaps and battens, battens may be required to be installed perpendicular to how they are supplied in the image. 2D images are not to scale, and for illustrational purposes only. Multifoils-Direct cannot be held responsible for any losses financially or physically from advice provided on this webpage