Guides
2026-03-27 · 9 min read
Thickness is easy to overlook yet often drives failures: waviness, machine damage, honeycomb telegraphing. This guide summarizes recommended gauges for ceilings, walls, door frames, and skirting, explains why ultra-thin stock is risky to process, and gives practical weight and sizing formulas for cost control.
Projects once chased lowest cost with 0.3 mm and thinner “paper” stainless. As owners raised visual standards, waviness, roller marks, and easy denting under lights drove massive rework. The market now favors full gauge and rigidity: drawings specify actual thickness, and premium jobs accept honeycomb-backed systems to keep large metal fields flat and crisp.
- Decorative cold-rolled sheet typically spans 0.3–3.0 mm. Above 3.0 mm is usually hot-rolled mill plate — too rough for direct decorative faces. - Common widths: 1000, 1219, 1500 mm; length cut to order (e.g. 2000, 2438, 3048, 3000 mm). - Weight (kg) = length (m) × width (m) × actual thickness (mm) × density (g/cm³). Use 7.93 for 201/304, 7.99 for 316, 7.75 for 430. Example: 1.219 × 2.438 × 1.0 × 7.93 ≈ 23.57 kg.
Based on Greateson’s field experience, we summarize thickness guidance below. (The detailed table from the source document could not be displayed outside Feishu; please confirm zone-by-zone thickness with your supplier using the same criteria as your internal spec.)
We treat 0.3–0.5 mm as “thin” stock. It can be made but is poor for quality zones: 1. 8K mirror polishing often grabs, rolls, or crashes thin sheets — very high scrap. 2. Handling leaves permanent roller marks and creases. 3. Flatness fails easily (>1 mm waviness is reject-grade) and looks cheap on the wall.
- Standardizing thickness and width speeds slitting and scheduling; many mixed specs force hunting coils and delay jobs. - Cost tracks weight; thicker sheet raises upfront kg cost but cuts rework and disputes.
- Myth 1: “Honeycomb lamination lets me use 0.5 mm mirror.” Truth: mirror telegraphs the core below 1.0 mm face — hex cells print through. Start mirror faces at 1.0 mm or more. - Myth 2: “Thin ceiling sheet saves weight.” Truth: lighten with honeycomb structure, not thinner solid sheet; bare steel framing plus thin sheet waves badly with temperature.
Flatness depends on thickness and incoming QC. Greateson cuts orders to major mills before 6 p.m.; next-day slitting checks peeling, weld spots, pinholes, and streaking. Waviness over 1 mm is rejected. Water marks from incomplete drying are screened. Stock destined for 8K gets additional scratch/probe inspection.
Correct thickness is the foundation of quality. Do not chase tiny savings with sub-0.6 mm sheet — waviness rework costs more. For large visual fields, especially mirror, remember two tools: increase gauge or use honeycomb.
Q1: Do mills differ in thickness and quality?
A1: Yes — a lot. Top-tier mills cost more (roughly CNY 5–6k/t) with flawless surfaces; Yongjin is a common 304 value leader; others may trade some flatness.
Q2: Are extra-wide or extra-long sheets easy to process?
A2: Difficult. Standard widths 1000/1219/1500 mm; 2000 mm coils exist but are harder to keep flat — usually 304 and ≥1.5 mm. Beyond 4000 mm length adds cost and difficulty.
Q3: Is nominal 0.6 mm actually 0.6 mm?
A3: Tolerance and under-gauge happen. Contract whether you mean nominal or full mic’d thickness; Greateson quotes on measured full gauge.
Q4: Is 0.5 mm OK for door frames?
A4: No — door frames take impacts; 0.5 mm dents too easily. Prefer roughly 0.7–1.5 mm.
Q5: Which density do I use?
A5: Use 7.93 for 201/304, 7.99 for 316, 7.75 for 430 in the weight formula.
Share your application scenario and expected finish, and we can provide a practical material recommendation.
