Install corrugated ASA PVC roofing from the downwind end, lapping each sheet one rib over the last, and fix through the top of the rib with sealing-washer screws and caps, about 4 – 5 per square meter. Pre-drill holes slightly larger than the screw shank so the sheet can move with temperature, and never over-tighten.
Step by step
- Check purlins are straight and in one plane.
- Start at the end away from the prevailing wind, so laps face downwind.
- Overhang the eave enough to drip into the gutter.
- Lap each sheet over the previous one by one rib.
- Pre-drill oversized holes through the crest of the rib.
- Fix with sealing-washer screws and ASA caps, snug but not crushing.
- Add more screws at eaves, ridge, corners and gables.
- Fit ridge and edge trims last.
5-wave ASA PVC sheet
Why oversized holes?
Plastic expands and contracts more than steel with temperature. A hole slightly larger than the screw lets the sheet move without cracking around the fastener; the sealing washer still keeps water out.
Cutting
Cut with a fine-tooth saw or a circular saw with a fine blade, sheet supported on both sides of the cut. Order sheets cut to length from Santiago to reduce cutting on site.
Santiago – a leading exporter of ASA/PVC roofing from Vietnam
Santiago roofing is produced and loaded into containers at our factory in Vietnam. It has been exported to India since 2023, Thailand since 2024 and the USA since 2025. Every export shipment comes with a commercial invoice, packing list, bill of lading and a certificate of origin (C/O) issued by Vietnam's Ministry of Industry and Trade, which importers use to claim the duty preference of their trade agreement.
| Item | Details |
|---|---|
| HS code | 3925.90.00 (ASA/PVC roofing sheets) |
| Certificate of origin | Form D (ASEAN), Form AI (India), Form AK / VK (Korea), Form AJ / VJ (Japan), Form VC (Chile), CPTPP proof of origin |
| Shipped from | Vietnam, by container |
Certificate of origin Form AI (ASEAN–India) for Santiago ASA/PVC roofing sheets, HS 39259000, certified on 24 September 2026. Buyer details are hidden.
The Santiago team beside a loaded export container at the factory, November 2024
Loading Santiago roof tiles into an export container
Frequently asked questions
Which way do I lay corrugated roofing?
Start at the end away from the prevailing wind so the laps face downwind.
Where do the screws go?
Through the top of the rib, never in the trough.
Why pre-drill bigger holes?
So the sheet can expand and contract without cracking.
Related products: ASA/PVC 5 waves · 6 waves · 11 waves · ASA/PVC roof tile · Skylight sheets
Contact Santiago: Santiago Import Export Co., Ltd, Vietnam. WhatsApp +84 935 391 495 (Mr. Quyen), hotline +84 965 437 316 (Mrs. Ly), email salessantiagoroofing@gmail.com.
Updated October 2026.
