Mr Quyen - Santiago. Posted 13/11/2026
A Santiago ASA/PVC tile sheet gives a garden room, summerhouse or log cabin in the UK a tiled look at about 5.4 kg per m² of roof, and in Santiago's tests rain on it is about 80% quieter than on metal sheet. It needs a pitch of 20 – 45% (about 11° to 24°). A 3 × 4 m garden room with an apex roof takes 8 sheets of 2.409 m. The sheets ship from Vietnam under CPTPP or the UK–Vietnam FTA; your planning office and building control decide what your project needs.
White single-storey house with a tile-sheet roof behind a fence, Vietnam
Why put tile sheets on a garden room?
Many garden rooms, summerhouses and log cabins end up with felt, shingles or a plain metal or polycarbonate sheet on top, because concrete and clay tiles are heavy for a small timber frame. The trouble is that the main house usually has tiles, and the building at the end of the garden then looks like a shed. A tile sheet closes that gap. It shows rows of curved tiles, one every 219 mm, yet the whole roof goes on as a few long sheets screwed to purlins.
Clay and concrete tiles are much heavier than the 5.4 kg per m² of a 2.5 mm Santiago sheet. We do not quote tile weights here; ask the tile maker for the installed weight if you are comparing, and let whoever designs the frame check it.
Is it quiet enough for a garden office?
Anyone who has worked under a thin sheet roof in a downpour knows the problem. In Santiago's tests, rain on the ASA/PVC sheet is about 80% quieter than on metal sheet, and the space under it stays 6 – 8 °C cooler than under bare metal sheet on a sunny day. Those figures compare one bare sheet with another. A garden office will also have insulation and a ceiling under the roof, which your builder designs, and that adds to the effect.
The sheet itself is four co-extruded layers without glue: an ASA top layer that carries the colour and blocks UV, virgin PVC, a PVC core and a milky-white PVC base. There is no metal in it, so nothing rusts at the screw holes or the laps.
White house with a grey tile-sheet roof, Vietnam
What roof pitch does a lightweight tile sheet need?
Between 20% and 45%, which is about 11° to 24°. That rules out the near-flat pent roofs many garden rooms have; below 20% this sheet is the wrong product, so do not try it on a low-pitch roof. A pent roof can work if it is steep enough, but an apex roof shows the tiles better from the house.
| Roof pitch | In degrees (approx.) | Tile sheet? |
|---|---|---|
| 10% | 6° | No, too flat |
| 20% | 11° | Yes, the minimum |
| 30% | 17° | Yes |
| 45% | 24° | Yes, the maximum |
| 60% | 31° | Steeper than the range; ask Santiago first |
The pitch also sets the height of the ridge. A steeper roof on the same footprint stands taller, and height is often what the planning rules care about, so settle the pitch with your designer before you order sheets.
How much do you need for a 3 × 4 m garden room? A worked example
Take a 3 × 4 m garden room with an apex roof, the gable end facing the house and the ridge running along the 3 m side. The roof faces fall across the 4 m width at 30% (about 17°) with 20 cm eaves. Along the ridge the roof is 3.84 m long, so it reaches 0.60 m past the front wall as a canopy over the glazed doors, and 0.24 m past the back wall.
| Step | Working | Result |
|---|---|---|
| Sloped length of each face | (2.0 + 0.2 m) × 1.044 for 30% | 2.297 m |
| Sheet length | 2.297 ÷ 0.219 = 10.5, round up to 11 steps; 11 × 219 mm | 2.409 m |
| Sheets per face | 3.84 m ÷ 0.96 m | 4 sheets |
| Sheets for the roof | 4 × 2 faces | 8 sheets, about 19.3 running metres |
| Roof area | 3.84 × 2.409 × 2 | about 18.5 m² |
| Screw sets with ASA caps | 18.5 m² × 4 – 5 per m² | about 74 – 93 |
| Ridge | Length of the ridge | 3.84 m of ridge cap and 2 ridge terminals |
| Eave sealing tile | Both eaves | 2 × 3.84 m |
| Sheet weight | 18.5 m² × 5.4 kg | about 100 kg |
Purlins go across each face less than 700 mm apart, at 440 or 660 mm so one sits under the foot of a tile step, with the top one 15 – 18 cm below the ridge. On a 2.409 m face that is about four or five rows. Pre-drill 6 mm holes and drive 70 mm screws through the top of the wave over a purlin, never in the valley, and lap each sheet over the next by one wave.
Small timber building with an orange tile-sheet roof under construction, Vietnam
Do you need planning permission or building regulations approval?
That depends on the size, height, use and position of the building, and on where you live in the UK, so check with your local planning office and building control before you start. Santiago does not hold certification under UK Building Regulations and publishes no fire, wind or snow rating for the sheet, so it does not claim that the roof meets any of them. Your designer or builder decides whether the sheet suits the project.
Buying from Vietnam under CPTPP or the UK–Vietnam FTA
The UK joined CPTPP in December 2024, and the UK–Vietnam FTA also covers trade between the two countries. Goods under HS 3925.90.00 can enter at a lower or zero rate under either route; your customs broker picks the better one and confirms the rate.
How do you get the sheets for one garden room?
Santiago's minimum export order is one 40 ft container, about 5,000 m of sheet with colours and accessories mixed, so a single garden room is normally supplied through a UK merchant or a garden building company that imports. Samples are free; the buyer pays the courier. The standard colours are dark grey, red, blue, orange and chocolate, with green, white and purple made to order. Santiago supplies the sheets and accessories and sends installation videos; it does not install. The warranty is 10 years for 2.5 mm and thicker, installed as Santiago recommends.
Garden pavilion with a brown tile-sheet roof by a pond, an installer on the roof, Vietnam
What does a tile-sheet roof look like from the factory to the finished building?
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. Installers carry a grey tile sheet into place, and the WhatsApp number is shown at the end.
Santiago uPVC tile sheets from the factory to the roof (Santiago video on YouTube).
Short videos for garden rooms and summerhouses in the UK
Two more English shorts from the Santiago YouTube channel. Each one is about a minute or less.
How tough is the sheet for a garden building?
Mr Quyen sets two blue sheets on the ground at the factory and a Santiago truck drives across them. It shows how tough the material is; the roof itself still needs purlins spaced less than 700 mm apart.
Truck test on Santiago ASA/PVC sheets (Santiago video on YouTube).
Which fittings finish the ridge of a summerhouse?
Red ridge caps and tile sheets stacked in the Santiago warehouse, filmed for buyers who order under their own brand (OEM).
Red ridge caps and tile sheets in the Santiago warehouse (Santiago video on YouTube).
CPTPP: lower import duty on roofing sheets made in Vietnam
Vietnam is one of the 12 member countries of the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), together with Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and the United Kingdom. Santiago ASA/PVC roofing sheets and accessories are made in Vietnam (HS 3925.90.00), so buyers in these countries can claim the CPTPP preference when they import them.
- Lower or zero import duty. Each member cuts its tariffs on goods of Vietnamese origin under its own CPTPP schedule, and many tariff lines are already at 0%. Your customs broker confirms the rate that applies to HS 3925.90.00 on the day of import.
- Proof of origin with every container. Santiago prepares the CPTPP origin documents for each shipment, so the importer can claim the preferential rate at clearance.
- Advance rulings. Under CPTPP, an importer can ask its customs authority for a written ruling on tariff classification and origin before the goods ship, so the duty is known before the order is confirmed.
- Faster, more predictable clearance. CPTPP members commit to publish their customs rules and, where possible, to release goods within 48 hours of arrival.
- The same preference on every repeat order. As long as the sheets are made in Vietnam and the origin documents are in order, each new container qualifies again.
Duty rates and paperwork change by country and over time: check the current rate and the proof-of-origin form with your customs broker before you order.
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
Are lightweight roof tiles any good on a garden room?
A 2.5 mm ASA/PVC tile sheet weighs about 5.4 kg per m², has no metal to rust and carries a 10-year warranty when installed as Santiago recommends. It suits apex and pent roofs with a pitch of 20 – 45%.
What is the minimum pitch for plastic roof tiles?
For Santiago's tile sheet the slope must be at least 20%, about 11°. Below that, choose a different roof covering.
Is a PVC tile roof noisy in the rain?
In Santiago's tests rain noise is about 80% lower than on metal sheet. Insulation and a ceiling under the roof reduce it further.
How many sheets for a 3 × 4 m garden room?
An apex roof with the ridge along the 3 m side, 30% pitch and 20 cm eaves takes 8 sheets of 2.409 m, about 19.3 running metres, 74 – 93 screw sets and 3.84 m of ridge cap.
Does the tile sheet come under CPTPP or the UK–Vietnam FTA?
Both routes exist for goods made in Vietnam under HS 3925.90.00. Your customs broker picks the better route and confirms the duty rate.
Read more
- How to install PVC roof tile sheets
- Santiago heat, noise and corrosion tests
- Gazebo and pyramid roofs: tile accessories
- PVC roofing sheet thickness and weight
- ASA/PVC roof tile sheet
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.
