1 / 16Thermal insulation membrane
Reflectiva GOLD — reflective thermal insulation foil and membrane, vapour barrier, attic insulation, 12 m²
Price includes VAT. Delivery across Romania, no minimum order.
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One pack covers 12.0 m².
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Calculate what you need for your attic- Product code5940031021931
- Weight28.9 kg
- ManufacturerIsoflect Insulation
The membrane that reflects radiant heat
Isoflect Gold is a vapour-barrier foil and reflective thermal insulation membrane with two faces of pure aluminium. It acts on all three modes of heat transfer — above all on radiation, on convection, by fully closing off air circulation, and with a conduction component — and stops water vapour, for insulating attic rooms, roofs, walls and ceilings.
Two layers of pure aluminium, core of bubble foil and expanded polyethylene. Total thickness ~10 mm.
Heat is transferred in three ways. Bulk insulation acts on two.
Conduction and convection are handled by the insulation between the rafters. Radiation remains — and in summer, the heat entering through the roof is largely radiant: the sun heats the roof covering, which radiates inwards.
Conduction
Heat passes through the mass of the material. Bulk insulation slows it down through thickness and structure.
Convection
Heat moves along with the air. Bulk insulation also reduces it by limiting air circulation.
Radiation
Heat travels as a wave, without needing air or contact. Only a radiant barrier repels it — exactly what Gold does, reflecting 95-97% back.
Tested in real-world conditions, not in a laboratory
Two identical structures, with identical interior volume. One insulated with a single layer of Isoflect Gold (10 mm), the other with 10 cm of glass mineral wool (λ = 0.032 W/mK). The same thermometers, the same conditions.
a single layer
10 cm thick, λ 0.032
at t1 (13:42)
at t1 (13:42)
How it works, in both seasons
Gold is installed on the warm side, facing the interior — the correct position for a vapour barrier in a cold climate (building science).
Reflects heat back upwards
The structure between the rafters heats up from the sun, regardless of Gold. Gold's role is to reflect the radiant heat back upwards, before it enters the room, while the sealed air layers on both faces hold between the rafters the heat that arrives by convection and conduction. The aluminium works on radiation, the sealed air on the rest — the room stays cool.
Keeps the heat — and the moisture — inside the house
Gold reflects heat back into the room, cuts off rising warm air and stops vapour from passing towards the cold zone. The rafters and the insulation remain cold, close to the outside temperature — but dry, because the warm, moist air no longer reaches them. Without that warm, moist front in the cold zone, condensation within the structure is significantly pushed back.
The same radiant barrier used by NASA
For the Apollo programme, NASA developed a thin aluminium foil that reflects 95% of radiant heat, applied to the base of the landing vehicles. The same technology went on to the James Webb Space Telescope and Skylab.
What you get in a roll of Gold
Composite membrane with a dual function: radiant barrier and vapour barrier, in a single product.
Technical data sheet
| Property | Value | Method / Standard |
|---|---|---|
| Physical characteristics | ||
| Width | 1.2 m | EN 1848-2 |
| Length | 10 m / 16.6 m | EN 1848-2 |
| Total thickness | 10 mm (±1) | EN 1848-2 |
| Total density | 460 g/m² | EN 1850-2 |
| Roll weight | 5.52 kg | — |
| Thermal radiation reflectivity | 95–97% | — |
| Emissivity | 0,05 | — |
| Tested characteristics — EN 13859-1:2010 | ||
| Resistance to water penetration (before and after artificial ageing) | Class W1 | EN 13859-1 |
| Tensile strength — longitudinal | 261 N/50 mm | EN 13859-1 |
| Tensile strength — transverse | 205 N/50 mm | EN 13859-1 |
| Elongation — longitudinal | 21,6% | EN 13859-1 |
| Elongation — transverse | 17,1% | EN 13859-1 |
| Tear resistance — longitudinal | 154 N | EN 13859-1 |
| Tear resistance — transverse | 199 N | EN 13859-1 |
| Water vapour diffusion (gravimetric method) | 190 | EN 13859-1 |
| Thermal resistance | 0.276 m²K/W | SR EN 22097:2023 |
| Thermal conductivity | 0.04707 W/(m·K) | ISO 8302 |
Accredited external test report: the specific technical characteristics are guaranteed by test report no. 7552000606-01, drawn up by INSTITUT PRO TESTOVÁNÍ A CERTIFIKACI – Czech Republic, in accordance with EN 13859-1:2010.
About the thermal values: the thermal resistance and conductivity in the table are measured on the membrane itself, without the adjacent air layers. In a real installation, Gold works together with the sealed air layers and through the reflection of radiation — mechanisms that cannot be reduced to a single conductivity value. This is why Gold is not assessed by thickness or lambda like a bulk insulation, but by function: radiant barrier + vapour barrier.
On its own it is strong. In a system, it becomes something else.
Gold works with any bulk insulation. In System 10, alongside Roof Pro, Wolle, Multistrat and the air layer between Phase 1 and Phase 2 of installation, each layer does a single job — and the assembly delivers a unique set of benefits, forming a unified whole that improves thermal insulation on every point of discussion.
Roof Pro / Eco — the breathable membrane
Above, beneath the roof covering. Watertight and windtight from the outside, but open to diffusion — it lets moisture escape upwards.
Wolle — the bulk insulation
Between the rafters. Handles conduction. Fibre made of recycled PET — no phenol-formaldehyde binder, no boron salts.
Gold — the radiant barrier + vapour barrier
Below the rafters, on the warm side. Reflects radiation back into the room and stops vapour heading towards the insulation. The third channel, closed.
All transfer paths
Conduction and convection through Wolle, radiation through Gold. The system no longer has the classic gap on radiation.
Vapour in a single direction
Gold blocks entry from the inside, Roof Pro ensures release to the outside — so the assembly can dry upwards and stays dry.
Useful for nZEB
The radiant barrier helps achieve the target thermal performance, and the vapour barrier contributes to the airtightness of the assembly.
Gold is in every System 10 package
From Basic to Premium — and in the "+" configurations — Gold (position 6) remains the common reflective component. The higher packages add layers over it; Gold is the constant.
System 10 Basic
- Wolle — white-fibre mineral wool
- Gold — radiant barrier + vapour barrier
- Sealed air
- Multistrat — sealed with Power Tape
System 10 Medium
- Everything in Basic
- Multistrat, layer 1
- Multistrat, layer 2
- Gold — still included
- Sealed air
- Multistrat, layer 3
System 10 Premium
- Everything in Medium
- Roof Pro — breathable membrane
- Gold — still included
- Optional: Silver / Bronze membrane
Conventional insulation handles conduction. Gold acts on all three paths: above all on radiation, reflected at 95–97%, on convection, by fully closing off air circulation, and with a conduction component. In Isoflect test in real-world conditions, adding Gold over conventional insulation delivered a significant additional performance gain compared with conventional insulation alone.
Installed exclusively below the rafters, on the inside
Isoflect Gold is a membrane for insulation carried out inside buildings. There is only one installation position — below the rafters, on the warm side — and it depends on a physical rule: aluminium only reflects when there is air in front of it.
📍 Position
Below the rafters, from the inside, over the bulk insulation. Over Gold, a batten structure is built which creates the air layer and supports the interior finish. Applicable to roof structures and buildings of any use: loft, habitable attic room, walls, ceilings, agricultural buildings.
💨 The air layer rule
Buy Isoflect Gold
Choose your preferred distributor and check product availability, or contact us directly for projects and System 10 solutions.
Frequently asked questions
Does Gold replace conventional insulation (wool, Wolle)?
No. Gold complements volumetric insulation (mineral wool, rock wool, glass wool or Wolle); it does not replace it. Conventional insulation handles conduction. Gold acts above all on radiation, fully closes off air circulation and adds a conduction component, plus the vapour-barrier function. Together, the system covers all three paths of heat transfer.
Where is it installed?
Exclusively below the rafters, from the inside, over the bulk insulation. Over the membrane, a batten structure is installed which creates the air layer and supports the finish. It is used on roof structures of any use: loft, attic room, agricultural buildings.
Why must it not be placed against OSB, timber or plasterboard?
Because aluminium only reflects radiation when there is air in front of it. Placed against a rigid body, that face loses its reflective effect — and aluminium, being a good thermal conductor, becomes a thermal bridge. One face may, however, be placed against the bulk insulation or the Multistrat foam, because these contain air.
Why on the warm side, facing the interior?
Because a vapour barrier is installed on the warm side of the assembly in a cold climate, in order to stop the warm, moist air before it reaches the cold zone where it would condense. The same position also allows radiation to be reflected back into the room. For the assembly to remain healthy, residual moisture must be able to escape to the outside — the role of the Roof Pro breathable membrane in System 10.
How does Gold differ from a variable-Sd membrane?
It differs in philosophy. A variable-Sd membrane changes its permeability according to the season: in winter it becomes more open and allows vapour to enter the insulation, relying on subsequent drying. Gold, on the other hand, is a firm vapour barrier, installed on the warm side — it stops the vapour before it reaches the cold zone of the assembly. In addition, Gold adds a function that a variable-Sd membrane does not have at all: the radiant barrier, which reflects 95-97% of radiant heat. In System 10, Gold blocks on the inside, and the Roof Pro breathable membrane lets residual moisture escape to the outside — the assembly breathes in a single direction and stays dry.
Does it contain hazardous substances?
According to the safety data sheet, Gold is classified as a non-hazardous product, free of volatile organic compounds (VOCs) and free of Radon. An inert, non-toxic material that does not absorb water and does not encourage mould.
Sources
- Product and performance data: Isoflect Gold technical data sheet and case study (S.C. Isoflect Insulation S.R.L.).
- Radiant barrier technology: Space Foundation, NASA Spinoff, Radiant barrier (overview).
- Position of the vapour barrier on the warm side: buildingscience.com — Understanding Vapor Barriers.
Add the channel that is missing from the system
Isoflect Gold closes off transfer by radiation and raises the performance of the entire thermal insulation system.
Plătiți în numerar către curier, în momentul livrării. Nu aveți nevoie de card și nu plătiți nimic în avans.
Garanție extinsă de 50 de ani la montaj în interior. Acoperă explicit tasarea și descompunerea materialului, se acordă fără pro-rata și înseamnă produsul pentru zona afectată, pe toată perioada.
No registration of the project and no condition to use only our own accessories. The term runs from the date of purchase and is proven with the purchase documents.
From the same range
Fitted together with
Isoflect Floor Pro — reflective thermal insulation foil and membrane for floors, vapour and radon barrier, 40 m²
Reflectiva BRONZE — reflective thermal insulation foil and membrane, vapour barrier, loft insulation, 40 m²
Reflectiva MULTISTRAT — reflective thermal insulation foil and membrane, vapour barrier, interior insulation, 30 m²
Reflectiva SILVER — reflective thermal insulation foil and membrane, vapour barrier, attic and wall insulation, 40 m²
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