Mr Quyen - Santiago. Posted 14/11/2026
For a roof over an open terrace or balcony, an ASA/PVC tile sheet weighs about 5.4 kg per m², keeps the space under it about 6 – 8 °C cooler than bare metal and makes about 80% less rain noise. Fix it to a frame your engineer has checked on the slab or parapet, give it a slope of at least 20% and lead the water to the terrace drains. An 8.0 × 4.5 m lean-to at a 30% slope takes 9 sheets of 4.818 m.
Grey tile roof over a terrace, Vietnam
Why put a roofing sheet over a terrace?
A flat concrete terrace takes the full sun all day and the full rain all season. A sheet roof on a light frame turns it into space people actually use: somewhere to dry laundry, sit in the evening, keep the water tanks in shade or build a rooftop room. It also keeps direct sun and rain off the slab, and so off the ceiling of the floor below.
What are the best roofing sheets for a terrace?
It depends on what the terrace is for and who sees it. From the street, a tile-sheet roof reads as part of the house; a corrugated roof reads as a utility cover.
| Terrace use | Sheet | Notes |
|---|---|---|
| Sitting area or rooftop room | Tile sheet, 1.05 m wide, 0.96 m cover | Tile look from the street; ridge and edge pieces in the same colour |
| Laundry, water tanks, storage | 5, 6 or 11-wave sheet | Plain waves, cut to the slope length |
| Part that needs daylight | Skylight sheets | 80 – 90% of light passes through; usually 5 – 10% of the roof area |
| Balcony | Tile sheet | Vertical wall flashing where the roof meets the wall |
All of them are 2.5 or 3.0 mm thick; 2.5 mm is the minimum for a roof. The ASA top layer showed no colour change after 2,000 hours of artificial UV, which matters on a rooftop where nothing shades the sheet.
Orange tile roof beside a balcony, Vietnam
Is there a waterproof & heat proof roof protection sheet?
People search for exactly this, and it mixes up two different jobs. A waterproofing membrane or coating is laid on the slab itself and stops water soaking into the concrete. A roof sheet sits on a frame above the terrace and keeps the rain off. A new roof will not repair a slab that already leaks; if yours does, fix the waterproofing first.
No roof sheet is heat proof. What a sheet can do is cut the heat: Santiago's ASA/PVC sheets keep the space under them about 6 – 8 °C cooler than bare metal sheet, because PVC conducts far less heat than steel. Light colours reflect more sun than dark ones. Keep the sides open, or leave vents near the top, so hot air under the roof has somewhere to go.
How is the frame fixed on a terrace slab?
This is the part to hand to a structural engineer or a builder you trust. The frame is anchored to the slab, beams or parapet walls, and wind on a rooftop is usually stronger than at ground level, so the anchors and the fixing pattern have to suit your building and your local rules. Santiago gives no structural, wind or fire rating. Some cities also need permission before you add a roof on a terrace; check before you build.
The sheet itself is light. At about 5.4 kg per m², a 40 m² terrace roof carries a little over 200 kg of sheet, spread across the frame. The frame and the wind load usually decide the design, not the sheet weight.
What slope and drainage does a terrace roof need?
A slope of 20 – 45%. On a terrace the usual shape is a lean-to against the stair-room wall or a high parapet, or a small gable over the middle of the slab. The rain collects at the low edge, so put a gutter there with a downpipe to the terrace drain or the building's downpipe, never onto the street or a neighbour's roof.
| Slope | Degrees | Rise per metre of run |
|---|---|---|
| 20% (minimum) | 11.3° | 0.20 m |
| 30% | 16.7° | 0.30 m |
| 45% (maximum) | 24.2° | 0.45 m |
A safety helmet on a grey tile roof, Vietnam
Worked example: an 8.0 × 4.5 m terrace roof
A lean-to fixed against the stair-room wall, 8.0 m along the wall and 4.5 m out across the terrace, at a 30% slope. The rise is 4.5 × 0.30 = 1.35 m, so the wall end sits 1.35 m higher than the outer beam. The length along the slope is √(4.5² + 1.35²), about 4.70 m. In 219 mm tile steps: 4.70 ÷ 0.219 = 21.5, rounded up to 22 steps, so each sheet is 22 × 0.219 = 4.818 m.
| Item | Calculation | Result |
|---|---|---|
| Sheets | 8.0 ÷ 0.96 = 8.3 | 9 sheets of 4.818 m |
| Roof area | 8.0 × 4.82 | About 38.6 m² |
| Purlin rows (660 mm apart) | 4.82 ÷ 0.66 = 7.3 spaces, so 8 | 9 rows |
| Screw sets | 38.6 × 4 – 5 | About 155 – 195 |
| Sheet weight | 38.6 × 5.4 kg | About 210 kg |
| Wall joint | The 8.0 m along the stair-room wall | Vertical wall flashing, counted on the quotation |
Screws go through the top of the wave over each purlin, never in the valley, with 70 mm screws, ASA caps and pre-drilled 6 mm holes. Lap each sheet one wave over its neighbour.
What is the best roofing sheet for a balcony?
A balcony roof is a small lean-to, and the same rules apply: 20% or more, purlins less than 700 mm apart, vertical wall flashing along the wall and a tidy edge where the side is open. Two things matter more on a balcony than on a terrace. First, where the water drops: a balcony roof without a gutter can drip straight onto the balcony below or the neighbour's window. Second, the underside is close to your eye. The standard base layer is milky white, which keeps the balcony bright; a dark underside can be made to order.
Do not stand on the sheets to clean them; they are not a walking surface. Reach the roof from a ladder or from inside, and lay boards across the purlins if someone has to go up.
Orange tile roof on a city rooftop, Vietnam
Why are terrace rooms under metal sheets so hot and loud?
A one-minute short with English captions: Mr Quyen explains why bare metal roofs are hot, noisy in rain and costly to repair, first in the factory and then on finished red and grey tile roofs.
Heat and rain noise: Santiago ASA/uPVC roofing explained (Santiago video on YouTube).
More short videos for rooftop rooms
Two short clips in English, filmed by Santiago. Tap a video to play it here on the page.
What does a finished grey tile roof look like by the gutter?
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).
From factory stock to a finished roof
Mr Quyen stands among stacks of brown tile sheets in the Santiago factory, then walks with a colleague along a finished grey tile roof near the gutter while installers carry a sheet into place.
Santiago uPVC tile sheets from the factory to the roof (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
Which roofing sheet is best for a terrace?
For a sitting area or rooftop room, a tile sheet in the house colour; for laundry or storage, a 5, 6 or 11-wave sheet. Santiago's ASA/PVC sheets are about 6 – 8 °C cooler underneath than bare metal and about 80% quieter in rain.
Will a roof sheet make my terrace waterproof?
It keeps rain off the terrace, but it is not a waterproofing layer on the slab. If the slab already leaks, repair its waterproofing first.
Is there a heat proof roofing sheet for a terrace?
No sheet is heat proof. ASA/PVC sheets reduce heat: about 6 – 8 °C cooler under the roof than bare metal sheet. Open or vented sides help hot air escape.
What slope does a terrace roof need?
At least 20% (about 11.3°), up to 45%. A lean-to 4.5 m deep at 30% rises 1.35 m.
Who checks the frame on a terrace slab?
Your structural engineer or builder, under local building rules. Santiago supplies the sheets and accessories and gives no structural or wind rating.
Read more
- Eave sealing tile or wall flashing: which edge piece goes where
- Keeping a house cool in the hot season: what the roof can do
- The underside of a PVC roof sheet as a ceiling
- How to install PVC roof tile sheets
- ASA/PVC roof tile sheet
Read next on this topic
Main guide: Roofing Sheet for Car Parking and Carports
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.
