Essential checklist for contractors, architects, and purchasing teams to submit precise BOQ inquiries, avoiding specification ambiguity and revision delays.
In commercial metal construction procurement, the primary cause of quotation delays and budget variances is underspecified tender inquiries. An inquiry stating simply "please quote 2,000 m² sandwich panel" cannot be priced with integrity because core chemistry, steel gauges, fire ratings, cut lengths, and flashings remain undefined.
1. Structural Dimensions: Ridge Run, Eaves Length, and Purlin Spans
The foundation of an engineered quotation is the project cutting list. What is the single-run distance from ridge to eaves? (e.g. 8.40 m). What are the secondary steel purlin centers? (e.g. 1.50 m). Without these metrics, factories price arbitrary stock lengths, resulting in 15% site cut waste and unsealed laps.
2. Insulation Core Chemistry & Fire Resistance (PIR vs. Mineral Wool)
Explicitly designate the core insulation: PIR B-s1, d0 for high thermal performance ($U$-value) and insurer compliance, or A1 Stone Wool (100–120 kg/m³) for certified boundary firewall assemblies.
3. Steel Substrates & Paint Chemistry (Top Skin / Liner Skin / Microns)
Steel mass represents the primary cost driver. Specify top skin gauge (e.g. 0.50 mm) and liner gauge (e.g. 0.40 mm), alongside standard RAL color codes (e.g. RAL 7016 Anthracite) and paint system (Polyester vs PVDF).
Comprehensive Engineering Comparison Matrix
| BOQ Inquiry Field | Deficient / Ambiguous Request | Engineered Specification (Recommended) |
|---|---|---|
| Product Scope | "2,000 m² roof panel" | 5-Rib PIR Roof Sandwich Panel (B-s1, d0, TS EN 14509) |
| Core & Metal Gauge | "Standard thickness" | Core: 50 mm PIR, Top Sheet: 0.50 mm, Liner: 0.40 mm |
| Coating & Color | "Grey color" | External: RAL 7016 Anthracite (25 µm PE), Internal: RAL 9002 |
| Cutting Schedule | "Standard truck lengths" | 120 pcs × 8.40 m + 60 pcs × 6.20 m (Exact custom cut) |
| Accessories Scope | "Quote flashings later" | 84 m Ridge Cap, 140 m Eaves Drip, 8,000 pcs Bi-Metal Screws |
| Delivery Terms | "Send ex-factory price" | DAP Project Site (Jobsite crane offloading by client) |
Submitting a complete BOQ schedule with exact piece lengths, metal gauges, RAL color codes, and flashings ensures same-day firm pricing and eliminates site installation delays.
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Frequently Asked Questions
Is sending architectural roof drawings recommended? ▼
Yes. Providing PDF or DWG drawings allows our engineering team to calculate optimum piece lengths and eliminate cutting waste free of charge.
Are fasteners included in the base square-meter price? ▼
Fasteners and flashings are quoted as distinct line items; standard practice requires specifying 3 to 4 saddle screws per square meter in the BOQ.