Below we have listed First Tunnels customers most frequently asked construction questions...
Burying surplus polythene would ensure that any gaps under the base rail will be sealed and will also reduce pest intrusion.
If you are positioning your polytunnel on an exposed site, then you may want to consider fitting extra door furniture to ensure that the doors remain firmly closed. Extra tower bolts and drop bolts would certainly help prevent the doors being damaged.
Our polytunnels can accommodate a slope providing it isn’t too excessive. If the slope is along its width then the foundation tubes on the lower side can be left protruding out of the ground by a maximum of 15cm. If the slope is more than this then you would need to have extended foundation tubes to ensure that there is enough tube fixed into the ground, please contact the office. For slopes along the length, then the polytunnel can be constructed as normal ensuring that the hoops are kept vertical. It may be necessary to clear some earth from the bottom end of the polytunnel to allow the door to open inwards.
I’m afraid it is not possible to alter the width of you chosen polytunnel but it is possible to shorten the length by setting the hoops closer together. The central ridge will require to be shortened and you may find it necessary to shorten stabilisers, etc.
The doors are designed to open inward or outwards. However, if fitting the door opening outwards is the only alternative, this can be performed after the main cover has been fitted. Detailed instructions for switching can be found in the construction guide.
You will find that your polytunnel becomes very hot in the summer and so we provide net panels for the top of the doors to aid ventilation. If you wish to substitute the net with polythene, you will probably find surplus polythene that can be used to screen off the net, once the main cover has been fitted. We also sell door ventilation blinds. If you have a polytunnel with sliding doors, then these can only be covered in polythene.
This is quite natural. The treatment process undergone by the timber causes many wood nutrients to rise to the surface whereupon fungus sometimes appears. It is entirely superficial and a wipe with a damp cloth or exposure to the natural elements will eradicate the fungus.
The tube has an internal weld and, although very rare it can be ‘rough and raised’ and makes slotting the tube together trickier than normal. Filing the weld should solve the problem.
The smallest width of polythene is 24ft, thus folds are a necessary and unavoidable requirement in order to facilitate transportation. A cover failing on a fold before its lifetime is reached, tends to suggest movement of the polythene (not tight). Your cover once fitted should be drum tight!
A claim for a replacement cover, due to premature failure will result in a request from the polythene manufacturer, for photographic evidence of the cover tension. We suggest taking a number of photographs demonstrating the tautness of the film shortly after construction.
We recommend that any snow be cleared from your tunnel as any excess weight can tear the polythene. On small tunnels a soft broom can be used to wipe off the snow. With large tunnels, a rope over the tunnel can be used, with a person at each end of the rope, walk along the length of the tunnel using the rope to dislodge the snow. You could also increase the temperature within the tunnel, this will allow the snow to slide off.
Although we take every effort to ensure that the timber supplied is free from any serious knots or other defects, timber is a natural product and not all such blemishes are identified. Due to the size, timber fixing battens are more liable to such defects and as a consequence you may find a number, that have snapped in two. Many offending defects can be cut out, and then simply use the ‘smaller than norm’ battens’ as you would with a 1.8m length, in fact, it is positively easier to work with shorter battens when fixing the cover.
We are more than happy to assist or provide further information relating to our polytunnels. You can contact us by email or telephone our office on 01282 601253. You could even become a First Tunnels Facebook Friend and share your gardening construction tips, growing advice, swap recipes, enter competitions and enjoy other fun things.