Commercial polytunnels: a buyer’s guide to new tunnels and re-covering
A low quote becomes expensive when a tunnel is poorly anchored, difficult to ventilate or covered with unsuitable film. Buyers comparing commercial polytunnels should look beyond frame dimensions and initial price. Access, exposure, working layout and maintenance all affect lifetime cost.
The same thinking applies to an existing structure. Polytunnel recovering is an opportunity to correct frame faults and improve the growing environment, rather than simply fitting another sheet over the hoops.
What should you assess before ordering a commercial polytunnel?
A specification starts with the crop and the way staff will use the tunnel. Propagation, soft fruit, salads and protected storage place different demands on ventilation, light and temperature. Check bed layout, irrigation routes, machinery movement and usable height at the sides, since nominal width can overstate practical working space.
Site details then determine whether the proposed frame suits the job. The site assessment should cover wind exposure, shelter, altitude, ground conditions, anchoring and bracing. Ask the supplier to explain how these factors have influenced the proposed specification and provide the warranty terms in writing.
Access problems often appear when the delivery vehicle arrives. Record gate widths, overhead cables, soft ground, turning space and the route to the build area. Extra carrying, lifting equipment or a smaller vehicle can change both the quotation and programme.
Ventilation and daily operation
Ventilation should reflect crop load and tunnel length. Doors provide useful airflow, although long structures often need additional side or end ventilation. Consider who will operate vents and whether insect mesh will restrict airflow.
Door size and position also influence workflow. Tractors, barrows and harvesting teams need clear entry points without damaging the film or frame. Small compromises here are repeated every working day.
Choosing the right polytunnel cover
Match film to crop, site and ventilation. Request the current film specification sheet and compare thickness in microns, total light transmission, light diffusion, thermal effect, anti-drip treatment and warranty period. Confirm that it is UV-stabilised and note which face must sit inward.
Clear film often suits crops where direct light is the priority, including lower-light propagation. Diffused film may suit leafy crops or dense canopies where even light and softer shadows help. These are not fixed rules. Crop, orientation, local light and heat control still matter, so compare the stated figures for each polytunnel cover.
Compare whole-life cost on one line per quote: film and preparation, fitting labour, access equipment, downtime, expected patch repairs, stated replacement interval and old-cover removal. Divide that total by the stated service years for a simple annual comparison. Check warranty exclusions too, since the lowest starting price may not be the lower-cost option.
What should happen before polytunnel recovering?
The old cover should come off early enough for a proper frame inspection. Covering over unresolved defects often recreates tears in the same places.
Run checks across the full structure, paying close attention to:
• rough or corroded hoop surfaces
• missing or damaged anti-hotspot tape
• loose timber rails and cover fixings
• exposed bolt ends, wire or sharp edges
• worn doors and repeated tear points
Complete any polytunnel repairs before tensioning new film. Anti-hotspot tape separates the polythene from warm or abrasive frame surfaces, but it cannot correct corrosion or sharp projections. Door frames and rails must hold the cover securely without creating concentrated stress.
Planning the fitting window
A large commercial cover requires coordinated labour, suitable equipment and a clear handling method. Film dragged across rough ground or caught by a gust can be damaged before fitting is complete.
Use the fitting limits in the selected film manufacturer’s current technical sheet, since temperature and wind limits vary by product. Cold film is harder to tension, strong sun can soften it, and wind can damage both the film and the team. Keep the date flexible and plan how production will continue while the tunnel is open.
Get a specification based on the site
PolytunnelsRus supplies, installs, repairs and re-covers polytunnels across England, allowing frame condition, cover choice and fitting scope to be reviewed together.
Contact PolytunnelsRus with the dimensions, site postcode, intended use, access details and photographs. Include wide views and close-ups of the frame, doors, fixings and wear, plus exposure concerns and your preferred working window. The next step is to review the site information and define the materials, preparation, fitting scope, warranty terms and exclusions needed for a comparable quotation. Confirm any site visit or survey charge before booking.
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