Single Span Greenhouse are a high-investment facility; a slight increase in investment can expand the indoor area.
Calculations show that for every meter the Greenhouse extends southward, the usable area increases by 11%, while the ridge height only needs to increase by 20 centimeters to achieve a relatively ideal roof angle.
Increasing the length of the Greenhouse is also a way to reduce investment and expand the planting area. More importantly, with increased indoor space, temperature changes are more stable, especially the slow cooling rate at night.
The front roof of the Single Span Greenhouse is a sun-receiving surface during the day and a heat-dissipating surface at night. Since its surface area is equivalent to the indoor land area, such a large heat-dissipating surface, if not properly protected, will negate even the best heat storage capacity of the walls and rear slope.
Currently, people mostly use straw mats to protect the front roof; the straw mat thickness should be at least 5 centimeters.
When covering the straw mats, the front mat should overlap the back mat, with at least 20 centimeters of overlap at the joint. A rainproof and insulating film should also be placed over the outside of the mats to prevent snowmelt and dew from wetting them and reducing their insulating properties.
Measurements have shown that greenhouses with rainproof film over their straw mats can have a temperature increase of approximately 1.5°C compared to greenhouses without rainproof film.