Scope of this guide. Published costs, savings and schedules are indicative examples, not a project quotation or guarantee. Compare the same location, specification and scope. Structural supply, civil works, building services, finishes and logistics must be confirmed separately; permit and engineering requirements depend on the site.
In short
- NewCon Steel® manufactures its CFS framing members from Zn-Al-Mg 275 g/m² steel (ZM275 to EN 10346 / ZMM275 to ASTM A1046): 275 g/m² total across both faces, roughly 137.5 g/m² per face.
- That is the same coating mass as Z275 / G90 galvanized and more than 50% above the ASTM A1003 G60 structural minimum of 180 g/m².
- The advantage of Zn-Al-Mg over galvanizing lies in its alloy chemistry, which protects the cut edge, the punch-out, and the screw.
- Nippon Steel reports 10 to 20 times higher resistance than conventional galvanized steel in salt spray (JIS Z 2371). In real atmospheric exposure, peer-reviewed literature records 2 to 4 times lower mass loss than hot-dip galvanized steel after 4 to 6 years.
- No coating is a service-life guarantee: the design sets the protection for the site's exposure, and the coating mass is verified with the mill certificate (mill test report, MTR) for the supplied lot.
NewCon Steel® manufactures its cold-formed steel (CFS) framing members, also called light-gauge steel (LGS), from Zn-Al-Mg 275 g/m² steel (ZM275 to EN 10346 / ZMM275 to ASTM A1046). That is 275 g/m² total across both faces (0.90 oz/ft²): the same coating mass as Z275 / G90 galvanized, and more than 50% above the ASTM A1003 G60 structural minimum of 180 g/m² (0.59 oz/ft²). The difference from galvanized steel lies not in the amount of coating but in the alloy chemistry, which better protects the cut edge, the punch-out, and the screw.
This guide explains what the 275 g/m² figure means and compares G60, G90, and Zn-Al-Mg in one table. It then separates the two corrosion tests that often get blended together and names the certificate to request before you issue a purchase order. It also states plainly what no coating guarantees.
What 275 g/m² means on a CFS member
Coating mass is stated in grams of metal per square meter of sheet, counting both faces. NewCon Steel specifies 275 g/m² total across both faces, roughly 137.5 g/m² per face. A buyer checks this number against the mill certificate, and reading it as "per side" would make the claim false.
The standard designation for this coating is ZM275 under EN 10346 and ZMM275 under ASTM A1046/A1046M Type 1. These are classes defined in public standards, so any mill's product can be checked against them. The coating is applied to the originating coil by the hot-dip process, before roll-forming.
NewCon Steel makes its LGS/CFS profiles in thicknesses from 0.85 to 2.5 mm (0.033–0.098 in), from base steel that complies with ASTM A1003/A1003M, the standard for coated sheet used in cold-formed framing members. These are the three figures you can check against published standards:
- 275 g/m² total across both faces (≈137.5 g/m² per face).
- The same coating mass as Z275 / G90 galvanized, with a different alloy chemistry.
- More than 50% above the G60 structural minimum (180 g/m²) in ASTM A1003.
G60, G90, and ZM275 side by side
The table compares three coating specifications that commonly appear in quotes for cold-formed framing. All masses are totals across both faces of the sheet.
| Coating | Mass (both faces) | Sheet standard | Protection at cut edges, punch-outs, and screws | Status under ASTM A1003 |
|---|---|---|---|---|
| G60 galvanized (Z180) | 180 g/m² (0.59 oz/ft²) | ASTM A653/A653M, hot-dip zinc | Zinc protects exposed steel galvanically; the cut edge, the punch-out, and the screw are where it fails first | The structural minimum for cold-formed framing members |
| G90 galvanized (Z275) | 275 g/m² (0.90 oz/ft²) | ASTM A653/A653M · EN 10346 | The same zinc mechanism, with more mass than G60 | Above the G60 minimum |
| Zn-Al-Mg ZM275 / ZMM275 (NewCon Steel) | 275 g/m² (0.90 oz/ft²; ≈137.5 g/m² per face) | ASTM A1046/A1046M Type 1 · EN 10346 (ZM class) | Magnesium and aluminum in the alloy migrate over exposed steel and form a protective film | Not listed in Table 1; qualifies through the ASTM A1004 route and sits more than 50% above the 180 g/m² G60 mass |
In practice, G60 is the minimum in the standard. G90 and ZM275 carry the same mass, so the choice between them comes down to chemistry and to performance in tests identified by their standard. If a quote promises "more coating" than G90 at the same mass, ask for the coating class and mass in writing.
Two tests, two different numbers
Zinc-aluminum-magnesium coatings are compared with galvanized steel in two kinds of test, and each one yields a different multiplier. NewCon Steel publishes both, with the name of each test, because they are not interchangeable.
- Accelerated salt spray (JIS Z 2371). Nippon Steel reports that Zn-Al-Mg coatings outperform conventional galvanized coatings by 10 to 20 times in corrosion resistance.
- Real atmospheric exposure. Peer-reviewed literature records mass loss 2 to 4 times lower than conventional hot-dip galvanized steel after 4 to 6 years of weathering, including marine exposure sites.
Salt spray has no linear correlation with real service life. Multiplying salt-chamber hours by a factor to predict years of service in Colón or on a Caribbean island is not valid. When a quote cites a single multiplier without naming the test, ask for the test standard and its conditions before you use the number in your specification. Both results are detailed on our engineering and standards page.
Cut edges, punch-outs, and screws: where corrosion starts
On a cold-formed member, corrosion starts at the cut edge, at the service punch-out, and where the screw goes in, because that is where bare steel is exposed. Those are the points where conventional galvanizing fails first.
The Zn-Al-Mg coating works at exactly those points. The magnesium and aluminum in the alloy migrate across cut edges, punch-outs, and fastener points, forming a protective film over the exposed steel. This is the verifiable mechanism behind the two test results above.
Fabrication matters too. NewCon Steel cuts, punches, marks, and labels every member by CNC in the plant, to a ±0.5 mm (±0.02 in) tolerance, so the crew does not cut or drill the steel in the field, and no cut edge needs a coating touch-up. Our bolted structural steel also avoids field welding. Welding coated steel destroys the metallic coating in the heat-affected zone, and a zinc-rich paint repair does not reproduce the factory coating.
ASTM A1003 and A1004: how an alternative coating qualifies
ASTM A1003 requires at least a G60 coating (180 g/m² across both faces) for cold-formed structural framing members. Its Table 1 does not list Zn-Al-Mg alloy coatings. These qualify through the alternative, performance-evaluated coating route (ASTM A1004), which requires at least the corrosion behavior of a G60 for Type H and Type L structural steels.
NewCon Steel's coating mass is 275 g/m², more than 50% above that 180 g/m² minimum. It is simple arithmetic that your specifier can check against public standards, without relying on the supplier's word.
To leave no room for interpretation, write the designation and the mass together in your specification: "Zn-Al-Mg ZM275 (EN 10346) / ZMM275 (ASTM A1046 Type 1), 275 g/m² total across both faces, ASTM A1003 base steel." Every alternative offer is then measured against the same reference.
Which certificate to request, and what it should show
The document that proves the coating is the mill certificate (MTR) for the Zn-Al-Mg coil. It states chemical composition, mechanical properties, and coating mass, and it is issued for the lot actually supplied. The certificate for your order therefore does not exist until you place the order.
You can request these documents on our technical documentation page. NewCon Steel issues them to match your project scope:
- Mill certificate for the supplied lot, including coating mass.
- Profile data sheet: section, thickness, coating, and base-material standard.
- Design standards statement, with the exact edition of each standard.
- Panamanian certificate of origin, for export shipments.
When it arrives, check three things: that the designation and mass match your specification, that the mass is stated as a total across both faces, and that the certificate lot matches the labels on the pieces. Every NewCon Steel member carries a label that traces back to the originating steel lot.
What a coating does not guarantee
A 275 g/m² coating is not 275 g/m² per face, and it is not a guarantee of service life in every environment. NewCon Steel does not publish a number of years of service, because real-world performance depends on the site, the construction details, and maintenance.
The project design sets the section, thickness, connections, and corrosion protection for the site's exposure. One orderly way to do that is to classify the site's atmospheric corrosivity under ISO 9223:2012, which runs from category C1 to CX, and then decide whether extra protection is needed. Other factors matter as well: whether the member sits inside or outside the building envelope, ventilation, condensation, and contact with other materials.
No coating replaces inspection. For buildings near the ocean, the maintenance plan should check edges, punch-outs, and fasteners in exposed areas, and it should record any mechanical damage that occurs during erection.
CFS framing in coastal areas: a specification checklist
If your project sits on the coast of Colombia, Panama, or a Caribbean island, this list covers what to put in writing before you request a quote:
- Coating designation and mass: ZM275 / ZMM275, 275 g/m² total across both faces.
- The site's corrosivity category under ISO 9223:2012, and any added protection the designer specifies.
- Members cut and punched in the plant, with no cutting or drilling in the field.
- Bolted connections with no field welding, and screws and bolts protected to suit the exposure.
- A mill certificate for each lot, and traceability from the label to the lot.
Our buying guide covers the rest of the data your quote request needs, and the FAQ answers the most common specification questions.
Who does what in the PEB Corp Group
NewCon Steel supplies the steel; SmartBrix Construction executes the construction; PEB Corp provides the engineering and the institutional relationship. If you need a finished building, the turnkey scope belongs to SmartBrix Construction, which publishes its cold-formed steel framing system for permanent buildings. The group's roles are explained on the PEB Corp Group page.
To get a quote, send quantities (lm, m², or metric tons; 1 t = 1,000 kg), profile thickness, and destination country. Request a steel supply quote → Reply within 24 business hours · technical proposal / quote in 48 h.