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Multi-Span (Gutter-Connected) Film Greenhouses
A multi-span greenhouse joins several bays side by side into one continuous growing space. The bays share gutters, so there are no walls or walkways between them. That makes it the standard layout for large commercial production, where heating, cooling, shading and irrigation are run as a single system.
Gutter-connected baysWhat is a multi-span (gutter-connected) greenhouse?
FANGCHENG designs and builds multi-span film greenhouses on hot-dip galvanized steel frames, covered with PE or PO film.
It is a greenhouse made of two or more spans connected along their eaves. The gutter between the spans collects roof water and ties the structure together. The terms multi-span, multispan, gutter-connected and ridge-and-furrow all describe this layout.
Why growers choose it
Better use of land.
There are no gaps or walkways between separate houses.
One climate to manage.
A large, continuous interior holds temperature more stably and makes air circulation easier.
Shared systems.
Shading, cooling and irrigation can be installed once and cover the whole area.
Easy to scale.
Bays can be added as production grows.
Open interior.
Planting systems, irrigation lines and automation fit easily and people move freely.
Steel arches and guttersStructure and materials
The frame is usually arch or Gothic in shape, which improves load-bearing and drains water. Main components are prefabricated and hot-dip galvanized for corrosion resistance. Column spacing, arch distance and span width are calculated to balance strength, material use and cost. The covering is PE or PO film. High-transparency film maximizes light, and UV-stabilized layers extend life. Polycarbonate sheets are often used on doors and gable ends, where durability matters most.
Arch roof or Gothic roof
A smooth curve that sheds rain and keeps film tension even. The common choice in mild and rainy regions.
A pointed top that sheds snow and condensation better, and gives more height near the sides.
Tap a side to compare.
Both carry film well. The choice depends mostly on snow and on how much headroom the crop needs near the walls.
Choosing span width, bay length and gutter height
A wider span means fewer gutters and columns, and more usable floor, but a heavier roof and a taller ridge.
Longer bays make fewer end walls but mean longer air paths and longer pipe runs.
A higher gutter gives more air above the crop and room for screens and hanging crops, but a taller structure carries more wind.
Closer spacing is stronger and costs more steel. We calculate it for your loads.
Roof gutterGutters: the part that makes it work
In a multi-span greenhouse the gutter is both a structural member and the drain for several roofs at once. Gutter material, thickness and coating matter, and so does slope and the number of downpipes. A gutter that is too small or poorly sloped overflows into the crop. Rainwater can be sent to storage tanks and reused for irrigation after filtering.
Gutters also set the working height of the house. Screens, hanging crops, irrigation booms and lights all sit below the gutter, so its height has to suit everything you plan to run inside. Changing it later means rebuilding, which makes it one of the first figures to fix.
Roof ventsVentilation and cooling
Ventilation is a key advantage of this layout. Common options are roof vents, side roll-up vents and sawtooth roof ventilation. In hot climates or for intensive production, exhaust fans, cooling pads and internal circulation fans can be added. Shading, internal or external, protects the crop at peak sun.
In a wide house, roof vents do the heavy lifting. Side vents only refresh the outer bays, so the middle of a large range depends on vents in the roof and on circulation fans. If you plan pad and fan cooling, the house length and the end walls are designed around it from the start.
Climate zones inside one big house
A multi-span greenhouse is one air space. If you want different conditions in different parts, plan for curtains or partitions at the design stage. These also help to stop pests and disease from moving freely along the house, and to hold heat in for one section on a cold night.
The trade-offs to know about
The whole area shares one climate, so you cannot hold different conditions in different parts unless you add curtains or partitions
Pests and disease can spread more easily in a single open space
The gutters shade a little of the crop
The initial investment is higher than for separate tunnels
None of these is a reason to avoid multi-span, but each needs a decision. Partitions answer the single-climate issue, hygiene routines and insect netting answer the pest issue, and a careful gutter profile keeps shading low. The higher investment is the one point only your business plan can settle.
Multi-span or single-span?
Single-span
Simple and lower in cost, suited to small farms, seasonal growing and trials.
Multi-span
More stable temperature, better airflow and central control, suited to commercial production and long-term operation.
Multi-span film rangeMulti-span film, polycarbonate or glass?
Compared with glass or polycarbonate, a multi-span film greenhouse needs lower investment and a shorter build time, and it is easier to extend. Glass and polycarbonate last longer and insulate better. Film suits growers who want to scale without heavy upfront cost.
Where it is used
- Vegetables such as tomatoes, cucumbers, peppers and leafy greens
- Seedling and nursery production
- Flowers and ornamental plants
- Research and demonstration projects
What these uses share is a need for one steady, managed climate over a large area. Where a farm grows many crops with very different needs, a multi-span range plus a few separate tunnels is often the more practical layout.
Bolted assemblyInstallation and upkeep
Most structures are assembled with bolts rather than on-site welding, which makes installation quicker and more consistent. Maintenance is mainly checking film tension, ventilation parts and drainage. Film is replaced every few years, while the steel structure lasts much longer.
What to settle before you order
Common mistakes with multi-span greenhouses
Choosing the span width before checking the crop layout
Sizing gutters for average rain instead of heavy rain
Leaving too little vent area for the size of the house
Not planning for expansion, so the next bay needs a rebuild
Treating ventilation, shading and cooling as separate jobs
Adding systems as you grow
Roof and side vents
These come first.
Shading and circulation fans
Added next.
Cooling and heating
Added after that.
Automation
Lastly.
A multi-span house can start simple and add systems in stages. Roof and side vents come first, then shading and circulation fans, then cooling and heating, and lastly automation. Plan the structure for the final layout, even if you build the systems over several seasons.
How to read a multi-span quotation
If two quotations leave out different items, they are not yet comparable. Ask both suppliers to complete the same list.
Common questions
Straight answers. If yours is not here, ask us.
A greenhouse of several bays joined at the gutter line, so they form one continuous growing space.
It is customized. We set span width, column spacing and arch distance from your crop, climate and land.
Yes, if the design allows for it. Tell us your plan at the start.
They can if their needs are similar. For very different needs, curtains or partitions help, or separate houses.
Not always. Roof and side vents may be enough in mild climates. Hot climates and intensive production usually benefit from added cooling.
It can cover a very large area, because bays are added side by side and in length. The practical limits are ventilation, drainage and the systems you plan, which we size with the layout.
Plan your multi-span greenhouse
Send your location, crop and area. We reply within 24 hours.
Consultation and project proposals are free.
What to include
- Location
- Your crop
- Planned area
- Reply within 24 hours
