What Is Aluminium Foil Insulation?
A straightforward explanation
Aluminium foil insulation is a reflective sheet made by bonding aluminium to a stable backing layer such as polyethylene film or paper. Once fitted and taped, it forms a vapour-resistant layer and helps reduce radiant heat loss. It works alongside primary insulation materials like mineral wool, PIR boards or underfloor heating insulation.
How it works
The aluminium surface reflects heat back into the room, helping the rest of your insulation do its job. Because foil membranes are light, easy to cut and clean to handle, they’re widely used in timber-frame buildings, roof refurbishments and modular construction where space and speed matter.
Common uses
- Underfloor heating systems
- Between timber floor joists
- Behind plasterboard in stud walls
- Under rafters in pitched roofs or lofts
- Warm-side vapour control in new builds and extensions
If you’re working on the outer roof layers, you can pair foil insulation with our breathable roofing membranes
Product Highlights
📦 Aluminium Foil 1 m × 50 m (50 m² Roll)
A great all-round vapour-control and reflective membrane for floors, roofs and walls. Often used under underfloor heating or behind plasterboard.
👉 View product: https://www.tradestoreonline.co.uk/product/aluminium-foil-1m-x-50m-50m2/
📦 Aluminium Foil Tape – 48 mm × 45 m
Reinforced foil tape for sealing laps, perimeter edges and service penetrations. Essential for keeping the vapour barrier intact.
👉 View product: https://www.tradestoreonline.co.uk/product/aluminium-foil-tape-48mm-x-45m/
Choosing the Right Foil Membrane
| Situation |
Product |
Notes |
| New-build pitched roof |
1 m × 50 m foil roll |
Fit on the warm side; tape all joints |
| Underfloor heating |
1 m × 50 m foil |
Reflects heat upward, reducing heat loss |
| Shallow cavities |
Bubble-foil (secondary option) |
For space-restricted areas |
| Sealing and repairs |
Reinforced foil tape |
Maintains airtightness and vapour resistance |
You can also browse our roofing accessories if you’re working on an entire roof system: https://www.tradestoreonline.co.uk/roofing-supplies/
Specification Overview
- Sizes: 1 m × 50 m and 1.5 m × 50 m
- Reflectiveness: up to 97% radiant heat resistance
- Multi-layer laminated construction
- Reinforced tapes available for a secure seal
- Suitable for walls, floors, roofs and modular building systems
How Foil Fits Into a Roof or Wall Build-Up
In many pitched roof systems, the foil sits on the warm side of the insulation, while a breathable membrane is fitted over the rafters. This approach helps keep the inside dry, supports airtightness and meets modern energy-efficiency requirements.
Breathable membranes available here
Foil Insulation vs Breathable Membrane
Foil insulation reflects heat and controls vapour; breathable membranes allow moisture vapour to escape while protecting the roof from wind and rain. They’re not alternatives — both are usually needed in a proper build-up, with the foil on the inside and the breathable layer on the outside.
Foil in Timber-Frame and Modular Building Work
Because foil membranes are light and clean to handle, they’re commonly used in garden rooms, loft conversions, timber-frame extensions and modular buildings. They help boost airtightness and provide reliable vapour control when paired with PIR boards or mineral wool.
Bulk insulation options
Why Order From Trade Store Online
- Free next-day UK delivery before 1 pm
- Strong trade pricing for bulk quantities
- Reliable supply across the roofing and insulation categories
- Helpful support if you’re unsure what you need
FAQ
Do I need an air gap?
Often yes, as the reflective surface works best with an air space. Some laminated foils can be installed tight to insulation — check the product notes.
Is aluminium foil a vapour barrier?
Yes. Once the joints and edges are taped, it forms a continuous vapour control layer.
Which way should foil face?
The reflective aluminium surface usually faces the warm side of the structure.
Can foil replace mineral wool or PIR boards?
No — it complements them. For main insulation layers, use PIR or mineral wool.
Is bubble foil still useful?
It can be in tight cavities but isn’t a substitute for full foil membranes or thicker insulation.
How Will My Aluminium Foil Supplies Be Delivered?
All orders are available with free next working day UK delivery and can be delivered straight to your door, warehouse or project site.
Same day dispatch is offered on any aluminium foil supplies, as long as both the order and payment is received before 1pm.
For more information about our next day delivery service, please read our FAQ page or contact our support team.
Summary
Whether you are looking for thermal insulation for various shaped areas, aluminium reflection foil or aluminium foil membrane, Trade Store has you covered.
Prevent heat loss within your home at competitive prices and discover the many benefits our aluminium products have including durability, reliability and affordability.
Contact Us
Our knowledgeable and professional team here at Trade Store are ready to offer advice and support on anything from identifying which aluminium foil product is best for your project, to ordering and delivery.
Please contact us via email at sales@tradestoreonline.co.uk or alternatively you can visit our FAQ page which gives information on frequently asked questions.
