| S.No. | Checkpoint | IS Requirement | Status |
|---|---|---|---|
| A. MATERIAL INSPECTION | |||
| A1 | Sheets are of correct type, grade and gauge per order specifications Acceptance: Gauge matches approved drawing; Galvanizing per IS 277 Table 1 | Cl. 4.2 — Conformance to specification | OK NC NA HOLD |
| A2 | Sheets are visually inspected for defects (dents, deformation, corrosion, coating damage) Acceptance: No visible damage, dents <2mm, galvanizing uniform without flaking | Cl. 5.1 — Surface condition requirements | OK NC NA HOLD |
| A3 | Sheets stored on level, raised platforms with protection from moisture Acceptance: Storage 1m above ground; ventilation gaps maintained; no pooling water | Cl. 6 — Storage and handling | OK NC NA HOLD |
| B. ROOF STRUCTURE & SUBSTRATE | |||
| B1 | Roof structure (purlins/trusses) inspected and confirmed free from defects Acceptance: All purlins level (±5mm/m); fasteners tight; no buckling or cracks | Clause 7.1 — Structural readiness | OK NC NA HOLD |
| B2 | Roof slope/pitch matches design (minimum 1:12 for water drainage) Acceptance: Slope 1:12 minimum measured; variation ±5mm per 1m | Cl. 7.2 — Slope requirement | OK NC NA HOLD |
| B3 | Underlayment/breathable membrane installed before sheet laying Acceptance: Membrane continuous, overlapped 150mm, no tears, stapled/fixed at 300mm c/c | Cl. 7.3 — Moisture protection | OK NC NA HOLD |
| C. SHEET LAYING & FIXING | |||
| C1 | Sheets laid in correct direction (corrugations perpendicular to slope; ridge toward up-slope) Acceptance: Corrugations perpendicular; no reversed sheets; consistent across roof | Cl. 8.1 — Installation orientation | OK NC NA HOLD |
| C2 | Sheets overlapped 150-200mm along slope direction (1.5-2 corrugations) Acceptance: Overlap measured 150-200mm; consistent across sheets; no undulating joints | Cl. 8.2 — Overlap requirement | OK NC NA HOLD |
| C3 | End-to-end lap joints are minimum 100mm with sealant application Acceptance: Lap ≥100mm; sealant applied full width; no gaps or skips | Cl. 8.3 — End lap sealing | OK NC NA HOLD |
| C4 | Fastening: one fastener per corrugation valley in each purlin intersection Acceptance: Fasteners at every valley at purlin; spacing ≤300mm; no skipped bays | Cl. 8.4 — Fastening specification | OK NC NA HOLD |
| C5 | Fasteners are stainless steel or hot-dip galvanized (matching sheet material) Acceptance: Fasteners stainless or galvanized; washers used; no rust/oxidation at heads | Cl. 8.5 — Fastener material compatibility | OK NC NA HOLD |
| C6 | Fastener holes are sealed with neoprene washers; no water pooling under heads Acceptance: Neoprene washers intact; no water entry visible; washers 20-25mm diameter | Cl. 8.6 — Leak prevention | OK NC NA HOLD |