Polycrub design

Our incredibly robust polycrubs are strong and durable in the harshest of climates.

The essence of the unique design of the polycrub is the incorporation of materials of different properties,  This creates a structure where each material complements the others. In a polycrub a twin-walled polycarbonate sheet is tensioned against a polyethylene pipe which is also under tension.

The gap between these two components requires a series of ‘couples’ to be established whenever a load is applied either from outside the structure or from within. Put simply the structure acts like a large spring, which distributes the forces all along its structure.

So what does this mean for the plants?

For plants to survive in any conditions they require light, heat and shelter.  Let’s look at each of these in detail:


polycrub’s come fully UV protected meaning that the most harmful of the sun’s light ‘Ultra-Violet rays’ cannot enter the polycrub. However over 80% of all the light useful for photosynthesis does enter.  Also the light which does enter the polycrub is distributed by the polycarbonate sheets, helping to avoid shading and over-exposure

light diagram polycrub

Another factor, which is often over-looked by polytunnel owners is the effect of wind-breaks, bunds and netting; all of which block out the available sunlight. Since polycrubs are designed to withstand all conditions,  wind-breaks are not necessary and all available sunlight is put to good use.


Although a polycrub will heat up in the sunlight similar to a conventional polytunnel or greenhouse, the air-gap in the polycrub’s outer skin provides an insulating layer which retains this heat.

The black polyethylene hoops also have a large thermal capacity which store up heat during the day and disperse it at night, acting like a natural storage heater.


Before any polytunnel or greenhouse can hope to offer any protection to plants it has to be able to cope with all circumstances. Polycrubs are designed to withstand strong winds, snow and frost, collisions from air-borne debris, and vandalism.

Polycrub: The 'strongman' of polytunnels. Robust. Durable. Resilient.