Mr Quyen - Santiago. Posted 03/11/2026
Santiago ASA/PVC roofing sheets have a milky-white PVC base layer, so the underside of the roof is bright and clean. Many warehouses, workshops and farm buildings leave it exposed instead of fitting a ceiling. The base layer resists moisture from below, and a dark underside can be made to order. Santiago does not make PVC ceiling panels for rooms.
White ASA/PVC sheets forming the ceiling of a factory, with lights fixed below
What does the underside of a PVC roof sheet look like?
It is white, smooth and follows the waves of the sheet. The sheet is co-extruded in four layers: ASA on top for UV and colour, then virgin PVC, a PVC core and, at the bottom, a milky-white PVC base. That base is the face you see from inside, whatever colour the roof is from outside, so a blue or grey roof still looks white from below.
A production hall with white ASA/PVC sheets as its ceiling
Do you need a ceiling under a PVC roof?
Warehouses, workshops, carports and farm buildings usually do without one. The underside is already finished, the roof itself keeps the space about 6 – 8 °C cooler than bare metal sheets, and rain noise is about 80% lower. Houses and offices often still fit a ceiling, for extra insulation, to hide wiring and lights, or simply for the look of a flat room.
Searches for "PVC ceiling sheet" usually mean the thin panels that line rooms. Those are a different product, and Santiago does not make them. This article is about roofing sheets seen from below.
Can the underside be another colour?
White is the standard. For a project that needs a dark underside, Santiago can mix the colour and produce the sheets separately, as a made-to-order item; ask for it on the quotation. Lights, fans and cable trays are hung from the purlins or the frame, not from the sheet.
A tape measure stretched across the white underside of a sheet roof during a site check
What about moisture under the roof?
The white base layer is there to resist moisture from below, and the sheet cannot rust when it gets damp. Buildings that make a lot of steam or humid air, such as animal houses and wet process halls, still need ventilation. An open ridge with a raised cover lets warm, wet air escape, and Santiago bends ridge cover pieces to size in the same colour and profile as the roof.
Can skylight sheets go in the same roof?
Yes. Translucent skylight sheets in the 6 or 11-wave profile can be laid among the ASA/PVC sheets to bring in daylight; plan about 5 – 10% of the roof area.
Daylight through clear sheets laid among white-backed ASA/PVC sheets
What do the top and underside of a Santiago tile sheet look like?
A Santiago worker stands on a white tile sheet laid on the factory floor, and a gas torch is pointed at red and blue sheets beside it. The short ends with the Santiago team in front of an export container and the WhatsApp number for enquiries.
Standing on a Santiago tile sheet at the factory (Santiago video on YouTube).
More short videos: the sheet on site and under heat
Three more English shorts from the Santiago YouTube channel. Each one is about a minute or less.
What does a grey tile roof look like from above during fitting?
In under a minute the short goes from the Santiago factory floor to a grey tile-profile roof on site: some sheets already fixed, installers screwing down the rest, and a finished run next to the gutter.
Santiago uPVC tile roofs on site (Santiago video on YouTube).
What happens when a flame is put to the sheets?
The heat-test short: grey and red sheets under a flame, Mr Quyen on grey sheets at the factory, then a warehouse roof re-laid in blue. It shows how the sheet behaves under heat, not a certified fire rating.
Heat test and a warehouse re-roof with uPVC sheets (Santiago video on YouTube).
How does the sheet behave when you cut it to length?
A 45-second factory short: beige and orange ASA/PVC sheets are flexed by hand and cut with shears to show how the material behaves. On a roof, purlins still go less than 700 mm apart.
Bending and cutting test on Santiago ASA/PVC sheets (Santiago video on YouTube).
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
Can a PVC roof sheet be used without a ceiling?
Yes. Santiago ASA/PVC sheets have a finished milky-white underside, so warehouses, workshops, carports and farm buildings often leave it exposed.
What colour is the underside of a Santiago PVC roof sheet?
Milky white, whatever the top colour. A dark underside can be made to order for a project.
Does Santiago make PVC ceiling panels?
No. Santiago makes ASA/PVC roofing sheets, roof tiles and skylight sheets, not interior ceiling panels.
Does the underside of a PVC roof get condensation?
The white base layer is made to resist moisture from below and the sheet cannot rust. Humid buildings such as animal houses still need ridge ventilation.
Read more
- Skylight roofing sheets: which profile and how many
- What Santiago's heat, noise and corrosion tests show
- PVC roofing sheet thickness and weight
- ASA/PVC roofing sheet, 11 square waves
Sources for the figures in this article
- Profiles, 2.5–3.0 mm thickness and 10-year warranty: Santiago ASA/PVC product specification.
- About 6–8 °C cooler than bare metal sheet and about 80% less rain noise: Santiago's own comparisons on finished roofs in Vietnam.
- HS code 3925.90.00: Harmonized System Chapter 39 (builders' ware of plastics), as applied in Vietnam's export tariff.
- Certificates of origin (Form D, AI, AK/VK, AJ/VJ, VC, CPTPP): issued by Vietnam's Ministry of Industry and Trade under the country's free trade agreements.
- Minimum order of one 40 ft container (about 5,000 m) and about 5 days for production and loading: Santiago export desk, October 2026.
Updated 03/11/2026. Santiago Import Export Co., Ltd, Vietnam. WhatsApp +84 935 391 495 (Mr. Quyen), hotline +84 965 437 316 (Mrs. Ly), email salessantiagoroofing@gmail.com.
