Your guide to purchasing a polyhouse
To ensure that you find your perfect polyhouse and an easy purchasing process, please read our guide:
In most cases, planning permission is required for these types of buildings. With our in-house design team, we can supply the necessary drawings to make an application for you.
Ordering the correct size
The size of a polyhouse is taken from the centre of the foundation tubes, down the length of the building. With single spans, the measurement is the outside of the hoop span to ground level. With multispans, you would take the inner span from the centre of the gutter to gutter.
We recommend that all our polyhouses are anchored using concrete foundations. As a rule of thumb, you will need 1 cubic metre for every 10 foundation tubes. For example, a 7m x 18m would need around 2 cubic metres.
Our polyhouses are more securely sealed than a conventional glasshouse. Ventilation and air circulation is vital for plant growth and health, therefore please select one of the following options for your polytunnel.
- Timber rails
Timber rails are a low cost, simple system and easy to install. The edge of the film is wrapped around a batten which is then nailed to a timber rail bolted to the polyhouse frame.
- Aluminium rails
Aluminium rails are an extruded grip rail cladding system for secure flexible sheeting. A base extrusion is secured to the structure framework and the cladding film stretched over it. The extruded aluminium infill section is then inserted into the base securing the film between the two components. Grip rail is extremely versatile and can be used with a wide range of different film thicknesses, simply using a different infill to match the cladding material used. These mid rails come complete with rail for each side of the relevant structure including a minimum 1.2m (94ft) return at each end. Fittings for fixing to the steel framework are also included. The height of these vents is dependent on the hoop profile.
- Roll up side vents
Roll up side vents system works by the film being wound around a tube, which is normally turned manually by a small gearbox unit. In certain situations, it can be electrically operated. This method is a very clean, neat system which can work on a curved side and retro-fitted if required. Roll up sides can also be used on gable ends of multispans if there are not too many door apertures.
- Gable-end vents (louvres)
The larger polyhouses can benefit from our effective butterfly vents. These can be arranged at high level, or low level, either side of the doorways in most polyhouses. Gable-end vents have a simple spring loaded 3-position hinge stay for variable ventilation rates. Other permutations may be possible on certain polyhouses, please contact us for details.
We offer a range of aluminium and timber ground rail kits. These can generally be fitted to any make of tunnel provided the foundation tubes are concreted in the ground and the hoop is fixed to the foundation tube.
- Aluminium box ground rails are a quick and easy system for fixing sheets that cannot be buried in the ground. Kits comprise aluminium extrusions for clamping to the funnel frame, fixing bolts and infills.
- Timber ground rails are a cheaper alternative and are essential to secure a lift-up side vent. Kits comprise 75mm x 50mm timbers for clamping to the funnel frame, fixing bolts and battens.
Timber end frames
Single span polyhouses are available with or without timber end frames, allowing you the option of designing or supplying your own end frame arrangement. The standard frame supplied is depicted on the relevant model specification.
To ensure you are ordering the correct amount of cladding, take the external hoop circumference as your measurement. The prices we quote take into the account the trenching of the polythene or netting at the sides of the tunnel, unless a ground level rail is being used. We include the cost of the anti-hot spot tape when ordered with a new polyhouse framework. If providing your own cladding, you must add at least 0.75m (2ft 6ins) each side to trench into the ground, or at least 0.3m (1ft) if cladding to a side rail.
Please note we strongly recommend the use of anti-hot spot tape between the steel tunnel frame and all claddings. For this reason, we include the tape in the pricing of the cladding when purchasing a new structure. The use of anti-hot spot tape can extend the life of these polythene films. It is important that anti-hot spot tape is replaced every second cladding, as the expected lifetime of the tape is 6-8 years.
BPI Visqueen film
- BPI Visqueen Lumisol ‘Clear’ 5S
Clear cover incorporating a UV ‘Transparent’ characteristic. This cover transmits a high percentage of UV light which can assist the colour, flavour and fragrance in a wide range of flower and full crops.
- BPI Visqueen Lumisol ‘Diffused’ 5S
Very high diffusing cover incorporating a UV ‘Transparent’ characteristic. This transmits a high percentage of UV light which can assist the colour, flavour and fragrance in a wide range of flower and full crops. In addition, UV transparent films promote plant anti-oxidants, which are good for health, and encourage stronger plants. This greatly benefits plant raisers and young plant growers as stronger plants can be easier to plant out thus saving time and raising productivity.
Bespoke sizes made using black tape net or Green monofilament net.
We offer a complete range of polythene to suit your growing requirements, and incorporate technologies to increase the strength of their films as well as offering all the features and benefits of other polythene films.
For polyhouse models which do not include cross-bracing as standard, this is available as an optional extra. Cross-bracing is a horizontal and vertical bracing arrangement across the span of a hoop. It can increase the resistance to snow and wind loadings particularly in exposed positions and can, in some instances, be used as a ‘crop support’ for the hanging of baskets/containers and irrigation lines.
Our door kits contain all the parts required: hinges, screws, handles and for sliding doors, our extruded aluminium top track and steel base rail. Please note that door kits do not include timber end frames. To establish the correct door and louvre options, please refer to individual products.
We can supply joinery made timber doors, either single or double, low cost hinged or sliding.
The small tunnels (up to 18ft/5.5m wide) can normally only fit hinged doors because of the lack of width for sliding. For these smaller tunnels the standard door panels are 6.6ft (2m) high and approximately 1.2m wide. For tunnels 21ft (6.4m) and wider, the doors are 6.9ft (2.1m) high.
We can supply aluminium framed sliding doors, clad with rigid polycarbonate and an aluminium base panel.