Thermafleece Breather Membrane
Key Information
 | Highly Breathable | Yes |
 | Highly moisture vapour permeable | Yes |
 | Waterproofing properties | Yes |
 | Vapour open | Yes |
 | UV resistant | 1 month |
 | Tensile and nail tear strength | Good |
 | Recyclable | Yes |
 | UKCA & CE Compliant | Yes |
 | Width (mm) | 1500 |
 | Thickness (mm) | <1 |
| Length (metres) | 16.7, 50 |
Made in Britain, Thermafleece Breather Membrane is a lightweight vapour permeable membrane for use in floors and walls, or on top of insulation as a protective layer
Thermafleece Breather Membrane has good water resistance, high breathability and is lightweight and easy to handle. The membrane is coloured black on one side and grey on the other with no text or images on either side.
Thermafleece Breather Membrane comprises 3 layers; two outer layers composed of a non-woven polypropylene and an inner breathable microporous film.
Installation
Do not leave the Breather Membrane exposed to weathering since high winds, excessive UV etc. may cause damage over time.
Always handle carefully to prevent tears and punctures. Repair any damage that does occur with . Ensure that sufficient ventilation is incorporated to comply with all relevant building regulations and technical standards.
Which way up?
There are two sides to Thermafleece Breather Membrane, a black side and a grey side.
- On a wall: the black side faces outwards, the grey side faces towards the inside of the building.
- On a floor: the black side faces the ground.
- In a roof: the black side faces the sky.
Please note: Thermafleece Breather Membrane is vapour open in both directions so if it is installed the wrong way around on a floor, it doesn’t impact performance. The black side has a higher UV stability, which is important for roofs and walls when the membrane is exposed to light during installation. This not relevant for floors
Walls
Typically, Thermafleece Breather Membrane is fixed horizontally.
- Start at the top of the wall with the first layer of membrane and fix with stainless steel staples or large-headed clout nails attaching to the wall studs at ~300mm centres / intervals.
- Overlap the next layer of membrane by 100mm horizontally and if necessary, by 150mm vertically. Do not begin a vertical overlap within 300mm of a corner detail.
- Overlap the membrane to cover the sole plate and if possible, extend the membrane 100mm on to the floor base.
- Seal over all fixings that penetrate the membrane, as well as all overlaps with air-tightness tape or silicon.
Floors
Thermafleece Breather Membrane is ideal:
- For supporting insulation between suspended floor joists.
- As a protective layer above insulation installed between floor joists to prevent the accumulation of debris.
Thermafleece Breather Membrane can be nailed or stapled to the underside of the floor joists if access permits. Alternatively, it can be installed from above the joists.
Installing Thermafleece Breather Membrane in a suspended floor that is only accessible from above:
- Make sure to place the membrane up against the masonry wall surrounding the floor so that the insulation is not in direct contact with the wall.
- Starting at the top of the first joist, staple the membrane in position. Run the membrane down the side and staple securely in place.
- Unroll the membrane across to the next joist and staple to the side securely. This will give a tight support and keep the insulation from moving once in situ.
- Run the membrane back to the top of the second joist and staple.
- Repeat for all joists. This will create a hammock effect with the membrane, where insulation can be placed between each of the joists.
- It is not necessary to full-fill the hammock space with insulation, but it is important that the insulation sits at the top of the joists. Make sure to measure the depth of your membrane 'hammocks' to fit accordingly.
Cutting tips
Cut Thermafleece Breather Membrane with a sharp edge knife or scissors. Take care not to puncture the membrane and repair any damage that does occur with suitable breather membrane or air-tightness tape.
Performance
| Artificial ageing – elongation | 40/50% (MD/CD) |
| Artificial ageing – resistance to water penetration | Class W1 |
| Artificial ageing – tensile strength | 200/100 N/50mm (MD/CD) |
| Elongation | 60/70 % (MD/CD) |
| Flame resistance | E |
| Resistance to air penetration | 0.03 m3/m2.h.50Pa |
| Stability to low temperature | -60°C |
| Tear resistance | 100/95 N (MD/CD) |
| Tensile strength | 250/140 N/50mm (MD/CD) |
| Vapour Resistivity | 9 MN·s·g-1m-1 |
| Water vapour transmission properties | 0.029 metres |
Pack Dimensions
25m2 roll:
- 120mm (d) x 1500mm (h) / weight: ~2.5kg
75m2 roll:
- 180mm (d) x 1500mm (h) / weight: ~7.5kg
Further information
Our Resources page has more details about how to install Thermafleece insulation products, natural fibre insulation, Thermafleece case studies and FAQs.
Any questions?
In an environment of conflicting information, we understand that choosing the right insulation for your project can be daunting. That’s why our team is on hand! We offer impartial and truthful advice as well as providing general technical help so feel free to call us on 017684 86285 or submit an enquiry via the Contact Us page.