PAGASA counts about 20 tropical cyclones entering the Philippine Area of Responsibility in a typical year, and roofs usually fail at the edges first: eaves, corners, gables and ridges, where wind suction is strongest. For ASA/PVC sheets, use at least 4 – 5 screw sets per m², more along the edges, stainless screws through the top of the wave, and purlins fixed firmly to the rafters.
Where does a roof fail in a typhoon?
Wind flowing over a roof lifts it; the suction is highest along the eaves, corners, gable edges and ridge. If one sheet or flashing lifts there, the wind gets underneath and peels the rest. Most failures start at the fixings, not in the middle of a sheet.
Edges, ridges and joints of a roof, where wind suction is strongest
Fixing checklist
- Screws: 4 – 5 sets per m² in the field, more along eaves, corners, gables and ridge.
- Through the top of the wave, with rubber washers and ASA caps.
- Stainless screws, so they do not rust and weaken.
- Purlins bolted or welded firmly to rafters; a sheet is only as secure as its purlin.
- Ridge and edge pieces screwed on every rib, not every other one.
What else should a builder check?
The design wind pressure for your location under the National Structural Code of the Philippines, the rafter and purlin sizes, and the connection of the roof frame to the walls. These are engineering questions; have a structural engineer check larger buildings.
Importing to the Philippines? Minimum order one 40 ft container (about 5,000 m), production about 5 days, Form D included: importer and distributor guide.
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
How many screws should a plastic roof have in typhoon areas?
At least 4 – 5 sets per m², with extra screws along eaves, corners, gables and the ridge.
Where do roofs fail first in a typhoon?
At the edges and ridge, where wind suction is strongest.
Should I use stainless screws?
Yes. Rusted screws lose strength and leak.
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.
