SF-80 is an FRP box purlin 80 mm tall and 40 mm wide with a 3 mm wall, weighing 1.33 kg per metre. With plastic roof sheets and purlin rows 660 mm apart it spans 2.5 m at 0.65 kPa and 2.0 m at 1.25 kPa basic wind pressure, which covers most houses and small stores.
| Item | SF-80 |
|---|---|
| Section | Box 80 × 40 mm, 3 mm wall, single cell |
| Weight | 1.33 kg/m (a 6 m length is about 8 kg) |
| Material | Pultruded FRP, no metal |
| Fittings | 304 stainless L-brackets, bolts, sleeves, screws and end caps |
How far can SF-80 span?
| Basic wind pressure W0 | 0.65 kPa | 0.95 kPa | 1.25 kPa | 1.55 kPa | 1.85 kPa |
|---|---|---|---|---|---|
| Maximum rafter spacing | 2.5 m | 2.2 m | 2.0 m | 1.8 m | 1.7 m |
For plastic roof sheets or ASA/PVC roof tiles, purlin rows 660 mm apart, deflection limit L/200.
Which buildings use SF-80?
Houses, shops, small stores, small animal sheds and fish stores on the coast, with rafters 1.5 – 2 m apart. A seaside house with 2 m rafters can use SF-80 up to 1.25 kPa; at higher wind pressure move to SF-100.
Why not a steel purlin of the same size?
Near the sea, night dew dissolves the salt on a steel purlin into a thin brine film. It eats the zinc first under the roof sheet and around the screw holes, where rain never rinses it. FRP contains no iron, so the same air does nothing to SF-80.
Frequently asked questions
What size is SF-80?
A single-cell FRP box 80 × 40 mm with a 3 mm wall, 1.33 kg per metre.
What rafter spacing suits SF-80?
Up to 2.5 m at 0.65 kPa, 2.2 m at 0.95 kPa, 2.0 m at 1.25 kPa, 1.8 m at 1.55 kPa and 1.7 m at 1.85 kPa basic wind pressure.
Can a seaside house with 2 m rafters use SF-80?
Yes, up to 1.25 kPa basic wind pressure. Above that, use SF-100.
All six sizes with the full span table: FRP Composite Purlin – SF Series.
Contact: 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.
