Commercial Timber Range Single Span
Our original Commercial Timber Range of polytunnels, offer an economical option over the Commercial Aluminium Range.
This is the traditional method of building polytunnels, with the polythene being fixed with timber battens nailed onto the timber door frames and side or base rails, it’s simple and cost-effective.
Our commercial range of structures use all the best materials available. Our timber is exclusively C16 and C24 grades, the steel is ArmourGuard zinc magnesium coated, and we manufacture the fittings in house which are designed specifically for Northern Polytunnels.
The foundation tubes have a greater wall thickness at 2.5mm, and the tunnels feature a cover tensioning system that allows you to adjust tension on the cover after it’s been fitted ensuring it maintains a tight, drum-skin finish.
Our in-house engineers have calculated the wind and snow loads for our structures to ensure that every polytunnel that leaves us can withstand the weather at your location
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Our commercial polytunnels are renowned for their strength which is why you can expect to see them in the most challenging environments, from the Shetlands to the Falklands.
The strength of our brackets and fittings have been proven for over 40 years and have been specially designed and manufactured in-house. Bespoke fittings are designed to simplify the construction process, thereby reducing the construction cost.
ArmourGuard® is NP Structure’s newly developed high-endurance galvanising treatment, giving extraordinary levels of corrosion resistance. ArmourGuard® offers up to 20 times the corrosion resistance of traditional zinc galvanising due to the combination of zinc, aluminium and magnesium.
Different crops and growing systems require different solutions, which is why we offer a range of options to suit your individual requirements and budget. Options include; doors & louvres - foundations - brace and crop bars - choice of polythene covers - ventilation systems and irrigation.
Visqueen’s British made polythene allows UVB, unlike normal glasshouse films (and glass) to enter the greenhouse which has many benefits including enhancing the fragrance, taste, colour of crops, with the added advantage of earlier harvesting and longer post-harvest shelf life. It also has a unique condensation reduction additive to further reduce light-loss. Our polythene is guaranteed for 7 years (incremental guarantee from invoice date)
Our Ground Tubes (Foundation Tubes) are 1m long, they are ArmourGuard galvanised treated with a 2.5mm wall thickness.
The image shows a Ground Tube concreted in with a ‘concreting bar’ to hold it securely
All of our foundation options incorporate our unique polythene cover tensioning system. The collar tensioning system enables a quick and easy tensioning of the polytunnel cover.
The hoops sleeve over the foundation tubes allowing each hoop to be raised individually and locked into position after the polythene sheet has been attached. This stretches the polythene cover to create a drum-skin finish. Unlike some manufacturers, our system allows easy tightening and slackening throughout the lifespan of the polytunnel
Our 4-pce hoop is made up of a 2-pce arch connected to a straight leg – making the tunnel stronger as the hoop is unable to “snake”. Manufacturing a hoop in this way also makes the hoop more customisable by giving the customer the ability to increase the height of the straight leg without compromising the stability of the single span.
Other manufacturers of Polytunnels often have their connections on the curve of the hoop which compromises the strength. To alleviate this, they use extra bracing brackets resulting in extra materials, extra costs and looks inadequate.
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If you want to talk to our in-house experts, call today and they will happily help you find a tunnel from our range to suit your needs.
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Foundation Options - Read More
Standard foundation tubes - Concreting method:
The recognised method when using traditional foundation tubes is to dig a hole (35cm square x 50cm deep) and set the foundation tubes in concrete. Considered to be one of the most secure methods. Generally only used where screw anchors aren’t suitable.
Base Plates (for concrete base)
Base plates are only used when fixing your polytunnel onto a solid concrete base or railway sleepers. Supplied with fixing bolts for securing in place.
Crop Bars - Read More
It might seem like an obvious statement, but the more steel in the structure, the stronger it is. You should choose; the “Inverted V” for lighter weather loading, or the sturdier “W-Hangers” for heavier weather loading, load bearing apparatus and crop support.
Formed from 50mm diameter, Armour-guard coated steel tubing, our crop bars and hangers are just as strong and durable as the hoops they service. Not only do they pin the hoops together, preventing lateral movement and joint loosening, but when fitted with “W-Hangers”, they’re strong enough to carry direct loading. This often seen in retail locations where large numbers of hanging baskets or planters are to be displayed. Crop bars also form the backbone of vital irrigation and air circulation systems as they are able to carry the additional load of water pipes, heaters and fans.
Our crop bars are just another reason why Northern Polytunnels produce the most robust tunnels on the market, specifically designed to stand up to the worst that the British winter can throw at them.
Polythene options - Read More
- Light transmission: Up to 92%
- Thickness: 720 gauge
- Thermic effect: Over 80%
- Diffusion: Less than 35%
- Light transmission: Up to 90%
- Thickness: 720 gauge
- Thermic effect: Over 80%
- Diffusion: 90%
- Light transmission: 60% - 70%
- Thickness: 720 gauge (180mu)
- Thermic effect: 55%
- Diffusion: 32%-33%
- Light transmission: 0%
- Thickness: 800 gauge (200mu)
- Diffusion: N/A - Blackout
Lumisol Clear is a UV ’open’ polythene film, allowing UV light to reach your plants. This can have many benefits for both edible and ornamental crops, such as enhancing the fragrance, taste, colour, earlier harvesting and longer post-harvest shelf life. In addition, UV open films promote plant anti-oxidants which are good for plant health and encourage stronger plants.
Due to its clarity, clear polythene allows around 2% more light to enter your polytunnel than with a diffused polythene cover. This extra light brings extra heat which can be a benefit during the early and late months of the growing season. Especially popular in northern and western regions where lower light levels naturally occur.
Light-diffusing polythene films scatter the light as it passes through the polythene. This enables the light to penetrate deep into the plant canopy, as it hits the plant from all directions, not just from the direction of the sun. This ‘diffused’ light reduces the higher foliage from shading the lower parts of the plant.
Lumisol Diffused is a UV ’open’ polythene film, allowing UV light to reach your plants. This can have many benefits for both edible and ornamental crops. Thanks to its unique anti-condensation additive, Lumisol Diffused is able to control condensation on the underside of the film.
White UVI polythene produces shade and reduces daytime temperatures, allowing 60-70% light transmission. A thermic film developed to help keep the growing environment warmer by reducing the heat lost through long wavelength infra-red radiation. Higher overnight temperatures encourage plant growth, can reduce plant losses and allow savings to be made on heating.
Ideal for: Crops that require shade and cooler daytime tempera tures such as nursery stock, ferns and conifers. The over-wintering of hardy shrubs and for general hardening off. Also widely used in the agriculture for general livestock housing and also general stor age.
Our standard shade net covers are dark green with a 40%-45% shade value, but heavier shade values can be catered for.
Our production method spaces the seams between 2m-3m apart (depending on the size), with the seams running parallel with the hoops (width-ways). Bespoke nets can be supplied which can include hemming and eyelets.
Green/White Polythene (Blackout)
Green & white polythene is especially formulated to meet the needs of the mushroom grower. The green outer layer helps this cover blend in with the environment, whilst the white layer reflects internal lighting to provide a pleasant working environment. A black core layer ensures complete opacity (black-out) and contributes to the durability of the film.
This film is also used for other applications, such as livestock housing, fish farms and protective structures. As this polythene is black-out, artificial lighting will be required.
Wiggle Wire Over Last Hoop - Read More
Wiggle wire C channel optional extras over the end hoops gives a flat covering on the end which not only makes it easier to fit the polythene but also gives a better finish to the gable end.
End Louvre Vents - Read More
Louvres are easily fitted to the ends of our structures. They can be used in conjunction with doors and the configuration can vary, depending on the size of your structure.
Louvre measurement: 0.79m x 2.12m
Actual ‘opening’ size: 0.8m x 2.15m.
Ventilation Louvres - Pull Cord (Gable end instead of a door)
These feature our unique 3 positional hinge which locks the louvre in place. This allows the louvre to be set in the fully open position, (90°) 1/2 open (45°) or closed. These can either be single row or a double row for extra ventilation
Ventilation Louvres - Rack and Pinion (Above the door)
These louvres feature a rack and pinion system for opening, controlled by a gearbox with winding handle. The rack and pinion louvres are fully adjustable, not just limited to the three positions like the pull cord louvres
Side Vent Options - Read More
Over a certain length, commercial tunnels can struggle with stagnant air in the middle that airflow from open doors cannot circulate.
The best recourse for this is to opt for some side ventilation. Whether manual winch, gearbox or motor-driven, it gives the grower control over the environment in the polytunnel. Opening the side vents allows air to flow throughout the tunnel reducing hot spots in summer. Closing them during cooler months reduces heat loss and encourages the grower to bring on plants earlier in the year.
Side vents are designed work in conjunction with open doors and/or roof ventilation, allowing full circulation through the tunnel.
Side Vent Automation
All our side vent options are able to be fully automated, with or without temperature control.
Basic Side Vent
• Timber Base Rails
• Timber Side Rails
• Timber Battens
• Full Depth shade net only (no skirt)
• Manual Gearbox
• Steel Curtain Tube
• Wind-Up Polythene Curtain
This is our entry level side vent. This system is available for polytunnels with timber side rails. The polythene screen and exterior netting are battened on to the side rails using wooden laths. The screen on this vent is polythene and clips directly onto a steel drive tube and is raised or lowered with a manual gearbox. There are no draft panels.
Professional Side Vent
• Timber Base Rails
• Timber Side Rails
• Timber Battens
• Full Depth net with PVC skirt
• Draft Panel Ends
• Manual Gearbox
• Aluminium Curtain Tube with Keder Slot
• Wind-Up PVC Curtain with Keder
This is our professional range side vent with a manual gearbox operating the internal roll-up PVC screen. This system is available for polytunnels with timber side rails. The PVC screen and exterior netting are battened on to the side and base rails using wooden laths. The netting comes complete with a solid draft-proof skirt and draft panels are also fitted to the mesh where the curtain ends, to minimise the cold air entering the tunnel. The PVC Screen fixed to the aluminium drive tube by a Keder and is raised or lowered with a manual gearbox. (An automation option is available)
Door Options - Read More
We only offer sliding doors on our commercial tunnels, over the years we have learned that doors on polytunnels work better for longer, if they slide rather than swing. We offer 2 models; a low-cost timber framed, clad in polythene and our new heavy duty aluminium frame, clad with PVC.
Both versions come with our aluminium profile sliding track and 4-wheel roller carriages.
Low-cost Timber Doors
3” x 2” timber with fixing battons
Nail plate joints
NP door furniture Door shoes fixing to the posts, drop bolt at the back of the door, door catch, small channel to hold the together when shut.
Heavy Duty Aluminium
Np designed aluminium door profile with wiggle wire fixing system
Clear PVC top panel
PVC grey lower panel
Steel, bolt on triangle corner plates
PVC finishing strip to cover the perimeter wiggle wire
Brush strip seal at the rear of the door (optional)
NP Designed door furniture, Door shoes to fix to the door posts, drop bolt at the rear of the door, full length channel section to form a seal between the doors, door catch.
Irrigation - Read More
Single Strip (Individual Bay Irrigation)
Ideal for single span polytunnels. Each spray-line waters half of the polytunnel, from the side to the central path. A special device on each nozzle ensures that most of the water falls uniformly within the strip. This allows you to have a different watering regime on each side of your tunnel without any overlap.
Ground Cover - Read More
With less than 5% light transmission, ground cover is an effective weed control fabric. Manufactured from black polypropylene (100gm/m2) with 25cm x 25cm green grid lines for accurate plant spacing.
Optimum water permeability (15ltr/m2/second). Ideal for above-ground or below-ground applications.
Danish Trolley Track Mat - Read More
The Danish Trolley track and ramp is easy to lay and move, and can be used as either a permenant or temporary track. The interlocking sections (end to end) ensure smooth and quiet trolley movement and are supplied in 1.2m x 0.54m interlocking lengths. The track is heavy-duty,long-lasting and made from recycled plastics, with a built-in anti-slip surface along the centre.
Quantity = length of the tunnel ordered
Polytunnel Roof Fans - Read More
These roof air extraction fans have revolutionised the way that polytunnels can be ventilated. These fans extract heat from the roof space of the greenhouse at its highest point. Which, in turn, draws cooler, fresher air in from the doors or side vents creating air movement in the structure. The 240v fans can be connected to either a simple on off switch, one of our fan controllers or a climate computer.
Air Circulation Fans - Read More
- Single Phase: 220v 50Hz 234W
- Fan Speed: 1,400rpm
- Single Phase: 220v 50Hz 234W
- Air Flow: 7,700m³/hr (3,240cfm)
Galvanised and powder coated for longer life. The aluminium blade supplies a big air flow up to 45m distance.