Greenhouse Structural Components

1. Greenhouse Structural Components Greenhouse Management

2. Structural Components • Greenhouses are made by assembling different parts or components. • Each part has a specific role in the overall greenhouse structure.

3. This slide shows the basic components of a greenhouse

4. Side Posts • Support the trusses and bear the weight of the greenhouse. • Set in concrete footings. • Typically spaced 10 feet apart.

5. Curtain Wall • The first several feet of sidewall above the soil line. • Usually made of some solid building material such as poured concrete, concrete blocks, bricks, or treated lumber.

6. Sill • The top of the curtain wall

7. Eave • Where the sides of the greenhouse join the roof of the greenhouse. • The “top” of the sides of the greenhouse.

8. Truss • Structural component that supports the weight of the greenhouse roof. • Consists of rafters, struts, and chords.

9. Purlin • Purlins run the length of the greenhouse. • Keep the roof trusses aligned.

10. Ridge • Where the roofs come together at the top of the greenhouse. • Many greenhouses have a ridge vent(s).

11. Sash Bars purlin • Run perpendicular to the purlins. • Attached to the purlins. • Hold the glazing in place. • Sometimes built with a drip groove or channel to catch condensation that forms on the inside of the glass panels. sash bars

12. Wooden Sash Bar Close-up Sash bar cap Glass panels Sash bar Drip groove

13. Aluminum Sash Bar Close-up

14. Sash Bar Cap Bar cap • Fastened to the sash bars with screws. • Functions to hold the glass panels in place.

15. Siting a Greenhouse • Topography • Select as level a site as possible. • Amount of land • The general “rule of thumb” is to purchase at least twice as much land as the desired growing area. • For example, you desire to build a ridge & furrow greenhouse measuring 50 feet x 150 feet. • 7,500 square feet x 2 = 15,000 square feet = .34 acres

16. N E W S Greenhouse Orientation • Depends on latitude and whether the greenhouse is connected or detached. • Single, detached greenhouse: • In northern latitudes an east-west orientation is favored because light can enter through the sides rather than through the ends of the greenhouse where it would cast more shade. • Also, because our winds are predominately from the west (blue arrow) this positions an end wall of the greenhouse into the wind.

17. Greenhouse Orientation • Connected Greenhouses: • An east – west orientation is not ideal. North South

18. Greenhouse Orientation South • Connected Greenhouses: • A north – south orientation is BEST! North

19. Windbreaks • Planted on the north and west sides of the greenhouse. • Help reduce heat loss from the greenhouse. • Greenhouses should be located a minimum of 100 feet away.

20. Framing Materials • Two basic kinds of material: • Wood • Metal; primarily aluminum or aluminum alloys

21. Wood • Redwood, cedar, or some other rot-resistant wood. • Treated wood. • Beware of mercury-based paints and preservatives because fumes from these products are toxic to plants.

22. Aluminum • Lightweight • Strong • Rust resistant • Framing materials can be manufactured thinner and be spaced further apart allowing for minimal shading.

23. Stresses on the Greenhouse • Weight of the framing and glazing. • Snow loads. • Wind pressure. • Temperature; fluctuating temperatures cause expansion and contraction of framing and glazing materials.

24. Headhouse Head House • Service building with overhead doors. • Used for planting, media preparation and storage, chemical storage, container storage and office space, etc.

25. Headhouse, continued… • May also include the heating plant (boiler) and a cold storage facility. • Should be at least 10% of the total growing area of the greenhouse.

26. The End