SYSTEM 04 · SAWTOOTH / PC
The sawtooth house: high light, snow shedding, polycarbonate cover.
A sawtooth roof with polycarbonate glazing. Popular where light levels are low, where snow has to slide off, and where a film roof would be replaced too often. The frame is heavier than a film house because PC sheet spans differently.
Sawtooth geometry solves two problems at once: the vertical glazing face admits low-angle winter light, and the sloped face sheds snow into the gutter. Polycarbonate is chosen over film where the cover has to last and over glass where impact matters. The cost is a steel frame that carries more roof dead load and a more complex purlin layout.
| Item | Value | Note |
|---|---|---|
| Span | 9.6 m | one sawtooth per bay |
| Bay | 4.0–4.5 m | along the gutter |
| Roof pitch | per design | snow shedding angle |
| Cover | 8–10 mm PC sheet | twin-wall or multi-wall |
| Purlin spacing | per sheet width | usually 0.5–1.0 m |
| Coating | hot-dip preferred | long service life |
PC sheet span tables are published by the sheet maker; purlin spacing follows them, not our preference.
Where the steel differs
- Purlin spacing is set by the PC sheet, so it is usually tighter than a film roof.
- The sawtooth adds a vertical glazing frame: more members per bay.
- Snow drift against the vertical face has to be considered by the designer.
- Sheet fixing needs a defined fixing line, so purlin punching has to be accurate.
Read next
Pages that answer the question this page raises.
- 05.03Venlo glasshouseVenlo glass greenhouse steel frame: 9.6 and 12.8 m spans, galvanised columns, trusses, gut→
- 05.01Multi-span film houseMulti-span film greenhouse frames: 6.2–12 m span, gutter-connected, galvanised oval arches→
- 04.04C / Z cold-formed profilesCold-formed C and Z steel purlins and rails for greenhouses: 80–120 mm profiles, 1.8–2.5 m→
- 08.03Snow loadGreenhouse snow load: ground snow load, shape and exposure coefficients, EN 1991-1-3 and E→
NEXT STEP
Quote a sawtooth frame against the sheet
Send the PC sheet type and span table. We will set the purlin spacing to it and price the extra glazing members.