Reinforced aluminum foil facing is a laminate of aluminum foil, fiberglass scrim and kraft paper (or polymer film), supplied in rolls for on-line lamination onto glass wool, rock wool and foam insulation. Most overseas insulation plants buy it as FSK: 7 micron foil, a tri-directional fiberglass scrim and 50 to 60 g/m² kraft, on rolls 1.0 to 1.3 m wide wound on a 76 mm core. Specify it in three passes: construction first (foil gauge, scrim pattern, kraft weight, adhesive system), then roll format (width, length, core, splice policy), then commercial terms (MOQ, lead time, Incoterms). A mistake in the first pass produces delamination claims months later; a mistake in the second stops your lamination line on delivery day.
Quick answer: what to specify before you order
- Name the construction by its layers, not by a trade name: foil gauge in microns, scrim pattern, kraft weight in g/m², and the adhesive or heat-seal coating.
- Decide the bonding method first, because it changes the facing construction: heat-seal coated facing for hot-line lamination, adhesive-bonded facing for glue lines.
- Confirm roll format against your unwind stand: width, length per roll, core diameter (76 mm is standard, 152 mm for jumbo), maximum roll weight, and how splices are marked.
- Ask for the paperwork with report numbers: ASTM E96 permeance, ASTM E84 25/50, tensile to ASTM D828, and the ASTM C1136 type the facing meets.
- Compare quotes at equal basis weight in g/m², not at equal width. Two facings can both be called FSK and differ by 30 % in material per square meter.
- Retain a sealed sample from every production lot. When a claim arrives six months later, that sample is the only thing that settles it.
One product, many names
International buyers describe this product in at least eight different ways, and a lot of procurement time is wasted on what are effectively synonyms. The table below maps the terms to what they usually mean.
| Term | What it usually means | Where you hear it |
|---|---|---|
| Reinforced aluminum foil facing | Foil plus scrim plus a backing layer; “reinforced” refers to the scrim | Generic trade name, common in Asian supply listings |
| FSK, foil scrim kraft | The same product named by its three layers | Standard term in US HVAC and metal building markets |
| FSK barrier, FSK vapor barrier | Buyer shorthand, sometimes meaning the faced blanket rather than the roll | Quotes and RFQs |
| FSV, foil scrim vinyl/PE | Foil and scrim on a polyethylene film instead of kraft | Humid climates, washable surface wanted |
| PSK, PP scrim kraft | White polypropylene film replacing the foil | Exposed indoor duct where a cleanable white face is wanted |
| MSK | Metallized PET film replacing the foil | Cost-sensitive volume work |
| WMP | US metal building facing family (vinyl-reinforced white or kraft) | North American metal building specifications |
| Foil fiberglass cloth | Foil on woven glass cloth, not scrim | Industrial, high-abuse, higher-temperature work |
| DS, double foil | Foil on both faces | Reflective assemblies, premium duct liner |
If your plant buys “reinforced aluminum foil” and the quotation arrives as “FSK facing”, you are almost certainly comparing the same product. Check the layer construction on the datasheet; that, not the name, is the specification.
The construction: five parameters that decide performance and price
Every roll of reinforced aluminum foil facing is built from the same ingredient list. What separates a good order from a bad one is whether each layer was chosen deliberately.
| Parameter | Typical range | What it changes | What to watch |
|---|---|---|---|
| Foil gauge | 6 to 9 micron standard; 14 to 25 micron heavy duty | Vapor permeance, cost, dead-fold behavior | Foil under 6 micron tears at the scrim bond points during winding |
| Scrim | 2-way or 3-way fiberglass; around 8×12 threads per 100 mm, or 5×5 and 12.5×12.5 mm meshes | Tensile MD and CD, tear resistance | Ask for threads per 100 mm, not a marketing word like “heavy mesh” |
| Kraft weight | 40 to 80 g/m², with 50 and 60 g/m² standard | Stiffness, bond to substrate, print quality | Light kraft wrinkles on wide rolls; heavy kraft adds basis weight and cost |
| Adhesive or PE coat | 20 to 25 micron PE for heat-seal; adhesive grams per m² for glue lamination | Line compatibility and temperature ceiling | Coating weight must match your line temperature and speed |
| Basis weight | 95 to 112 g/m² for a standard FSK build | The number your price per m² actually reflects | Compare offers at equal basis weight or you are comparing nothing |
The scrim deserves a paragraph of its own, because it is the layer people underestimate. The foil carries the vapor barrier and the reflectivity, but the scrim carries the load. A 7 micron foil on its own has a tensile strength you can measure with your hands; put a tri-directional fiberglass scrim behind it and the same facing pulls 30 lb/in or better in the cross direction. When a salesperson offers a lower price, the scrim count is the first place to look for what was given up.
Construction is only half the story. The other half is how the facing pairs with the substrate on your line, which we cover substrate by substrate in the FSK laminate guide.
Heat-seal or adhesive lamination: buy the facing for your line
The single most expensive specification error is ordering a facing whose bonding system does not match the line it has to run on.
A heat-seal coated facing carries a polyethylene layer that softens in the lamination calender and bonds the facing to the glass wool or rock wool directly, with no glue on the line. An adhesive-bonded facing expects the plant to apply its own adhesive. Both produce a faced blanket, but the facing constructions differ: the heat-seal version needs a coating weight matched to your calender temperature and line speed, and the adhesive version needs a kraft or film surface that wets out with your glue.
Run the trial on your line, at your speed, before committing to a container. The heat-seal versus adhesive lamination decision changes peel strength, throughput and cost per square meter, and it is cheaper to learn on a sample roll than on 20,000 square meters of facing.
Roll format: width, length, core, and the details that stop lines
Construction decides whether the facing works. Roll format decides whether it works on your line on the day it arrives.
| Parameter | Typical value | What goes wrong when it is ignored |
|---|---|---|
| Width | 1.0, 1.2, 1.25, 1.3 m | A 10 mm width error misaligns the edge flap and the tape line for the whole blanket |
| Length per roll | 100, 300, 1,000, 2,500 m | Jumbo lengths need an unwind stand that can take the weight; short lengths mean constant changeovers |
| Core diameter | 76 mm (3 in) standard, 152 mm (6 in) jumbo | Wrong core and the chucks simply do not fit |
| Roll outside diameter and weight | Set by your unwind stand limit | Overweight rolls get manhandled or rejected at goods-in |
| Splices | Should be flagged with colored tape, count agreed | Unmarked splices jam the line at speed and can wreck a calender wrap |
| Print repeat | Logo repeat length matched to blanket cut length | A print repeat that fights your cut length wastes printed area or prints half a logo |
Width tolerance is worth pinning down explicitly. Ask for it in millimeters, get it in writing, and check it at goods-in with a tape measure on the first roll of every delivery. Mills that control width to plus or minus 2 mm will say so; the ones that cannot will change the subject.
Documents and certifications for export markets
Faced insulation does not cross borders on a datasheet alone. What your customer’s market demands decides what the facing must prove, and it is far cheaper to collect the documents at the mill than to retest a finished product that was refused entry.
| Market | Fire evidence commonly demanded | Performance evidence | Paperwork to ask the mill for |
|---|---|---|---|
| US and Canada | ASTM E84, 25 flame spread / 50 smoke; NFPA 90A and 90B for duct work | ASTM C1136 type compliance | E84 report with number and date, COA per lot |
| European Union | EN 13501-1 Euroclass for the finished product | Permeance to EN ISO 12572 practice | REACH compliance statement; note the finished blanket carries CE marking, not the facing alone |
| United Kingdom | BS 476 Class 0 or Class 1 | Equivalent BS EN tests | Same as EU plus project-specific approvals |
| Australia and NZ | AS 1530.3 | AS/NZS 4859.1 for the insulation | Test reports referenced to the Australian standard |
| Middle East | BS 476 commonly referenced, civil defense approvals | Project-specific | Reports in English, attested where required |
Backed aluminum foil is commonly declared under HS code 7607.20, and your customs broker will want the foil thickness and backing described on the shipping documents, so keep the construction sheet consistent from quotation to invoice.
How to qualify an insulation facing supplier
A facing roll is a commodity only until it jams your line. Before the first container, work through this list.
- Request a construction sheet with every layer named and gauged: foil thickness, scrim type and thread count, kraft weight, adhesive or PE coating weight, total basis weight.
- Ask for test reports with report numbers and dates: permeance to ASTM E96, surface burning to ASTM E84, tensile to ASTM D828 in both directions.
- Confirm which edition of ASTM C1136 the type claim refers to, because type definitions have changed between editions.
- Get a sample from current production, not a laboratory hand sheet. Hand samples wind better than any production roll ever will.
- Run the trial at your line speed and temperature, and keep the trial roll until the first production delivery matches it.
- Agree the splice policy in writing: maximum splices per roll, and how each one is flagged.
- Fix the print specification: artwork position, repeat length, ink type, and whether a UL or other listing mark has to survive on the exposed face.
- Decide on perforation early. Full-coverage perforation suits facings used unbonded; channel perforation lets adhesive-bonded lines run without glue bleed-through.
- Require a retained sample and a certificate of analysis for every production lot, referenced to the roll numbers shipped.
- Check real capacity: daily output in square meters, and what the mill does with your order when a bigger customer is late. The answer to that question is worth more than any certificate.
Commercial terms: MOQ, lead time and container loading
Typical market figures for standard FSK constructions run from one or two pallets for stock constructions up to a full container for custom grammage or printed work, with lead times of 15 to 30 working days after artwork and specification sign-off. Treat those as market-typical ranges, not commitments; every mill sets its own, and they move with foil prices.
Three things protect you commercially. First, quote per square meter at a stated basis weight, so that offers are comparable and so that nobody quietly lightens the kraft. Second, agree Incoterms (FOB and CIF are the common ones for this trade) and confirm who books the container. Third, get the loading plan in writing: rolls per pallet, pallets per container, gross weight, and whether rolls ship in poly bags with end protectors. A container of unbagged rolls that absorbed sea humidity arrives as a claim, not as insulation.
Common specification mistakes
- Comparing quotes at the same width but different basis weights. The cheaper roll is usually just lighter.
- Ordering heat-seal coated facing for a glue line, or adhesive-bonded facing for a hot line. Both run badly and both are your problem, not the mill’s.
- Treating foil gauge as a proxy for strength. The scrim does that work; a 7 micron foil with a good 3-way scrim outperforms a thicker foil with a sparse one.
- Leaving core size and width tolerance to chance. These are the two errors that physically stop lines, and they cost nothing to specify correctly.
- Skipping the retained sample. Without one, a delamination claim six months later is your word against a shipment that has already been installed.
FAQ
What is reinforced aluminum foil facing?
It is a laminate of aluminum foil, fiberglass scrim and a backing layer (usually kraft paper, sometimes a polymer film), supplied in rolls for on-line lamination onto insulation such as glass wool, rock wool and foam board. The foil provides the vapor barrier and reflectivity; the scrim provides tensile strength; the backing provides stiffness and the bond surface.
Is reinforced aluminum foil facing the same as FSK facing?
For practical purposes, yes. FSK (foil scrim kraft) is the most common construction, and “reinforced” describes the fiberglass scrim inside it. The terms are used interchangeably in trade. The reliable check is the construction sheet: if it lists foil, scrim and kraft, the two quotes describe the same product.
Which foil thickness should I choose?
Six to 9 micron covers most duct wrap and metal building work, with 7 micron the common middle choice. Fourteen to 25 micron suits heavy-duty industrial cladding and work where the foil must survive more handling. Thicker foil raises cost quickly, so do not buy 18 micron if the facing spends its life under a metal jacket.
What roll width, length and core size are standard?
Widths of 1.0, 1.2, 1.25 and 1.3 m are the common slitting options; lengths run from 100 m up to 2,500 m on jumbo rolls; and the 76 mm (3 in) core is the industry standard, with 152 mm (6 in) on jumbo rolls. Match all three to your unwind stand before you sign, because these are the values that physically fit or do not fit your line.
What MOQ and lead time are typical?
Market-typical figures are one to two pallets for stock constructions and a full container for custom grammage, print or perforation, with 15 to 30 working days of production after specification sign-off. Foil price movements and peak season can stretch both, so confirm them in the quotation rather than assuming last year’s terms.
Can the facing be printed with my logo?
Yes, and most insulation plants print the facing with a brand name, product data or listing marks. Specify artwork position, repeat length matched to your blanket cut length, and ink that survives the lamination temperature. If a UL or other certification mark is printed, the mill needs authorization for it and the mark must remain legible on the exposed face after lamination.
Do I need perforated facing for glass wool lamination?
Only for adhesive-bonded lines. Channel perforation gives the glue somewhere to go and prevents bleed-through staining on the foil face. Full-coverage perforation is for facings used unbonded, where vapor needs to pass through deliberately. Heat-seal lines generally do not need perforation at all.
Next step
If you are sourcing facing rolls for a glass wool, rock wool or foam lamination line, send us your line parameters (bonding method, line speed, calender temperature, roll width and core) and the export market, and we will quote a construction that runs on your line rather than one that merely looks right on paper. Request a specification or sample here: Contact Donfoil.
