Polyrope Guides • Polytunnels
If your polytunnel cover has turned cloudy, brittle or started to tear after a few seasons of Irish wind and rain, it is time for a new one. The biggest decision is thickness: 720 gauge or 900 gauge. Both will grow good crops — the difference is how long they last and how much punishment they can take.
Quick answer
- Choose 720 gauge (UV4) for a budget re-cover on a sheltered site — it is UV-stabilised for a minimum of 4 seasons.
- Choose 900 gauge (UV10) for exposed, windy sites or if you don’t want to re-cover again for a long time — it is rated for a minimum of 10 seasons.
- Covering a 10 m wide tunnel? The 10 m width is available in 900 gauge.
What “gauge” and “UV” actually mean
Gauge is simply the thickness of the film: 720 gauge is 180 micron, 900 gauge is 225 micron — about 25% thicker. UV refers to the stabiliser mixed into the polythene that protects it from sunlight. The number tells you the minimum number of seasons the film is designed to last: UV4 means at least 4 seasons, UV10 at least 10.
720 vs 900 gauge at a glance
| 720 gauge (UV4) | 900 gauge (UV10) | |
|---|---|---|
| Thickness | 180 micron | 225 micron |
| Designed lifespan | minimum 4 seasons | minimum 10 seasons |
| Structure | 3-layer horticultural film | 3-layer COEX-3 film, made in Germany (Gardenvit), ISO 9001 |
| Light transmission | high light permeability | up to 92–94%, with even light diffusion |
| Heat absorption | over 80% | over 80% |
| Temperature range | −40°C to +50°C | −40°C to +50°C |
| Widths in stock | 6 m, 8 m | 6 m, 8 m, 10 m |
| Cut to length | from 2 m up to 33 m | from 2 m (up to 22 m on 10 m width) |
Which one is right for you?
- Go for 900 gauge if: your tunnel stands on an open or coastal site, it is a large tunnel that catches a lot of wind, or you simply want to fit a cover and forget about it for the next decade.
- 720 gauge makes sense if: your garden is sheltered, the tunnel is small, or you are planning to replace or move the structure within a few years.
The price difference per metre between the two is small compared with the cost and effort of re-covering, so on an exposed site the heavier film is usually the better long-term buy.
Signs it’s time for a new cover
- The film has gone cloudy or yellow. Less light reaches your plants and growth slows — especially in spring and autumn, when light is already short.
- It feels brittle or cracks when you press it. Once the UV stabiliser is used up, polythene breaks down quickly.
- Tears keep appearing along the hoops. This is usually heat damage where the film meets the steel frame — a good reason to tape the frame when you fit the new cover.
- The cover has stretched and flaps in the wind. A loose sheet wears out fast and can tear away in a storm.
How to measure for a new cover
Measure over the top of a hoop, from the ground on one side to the ground on the other — that is the minimum width of sheet you need. Then add extra on both sides for trenching or fixing the edges; how much depends on your fixing method. For the length, take the length of the tunnel and add enough at each end to cover the end walls and fix the film. If you are unsure, send us your tunnel dimensions and we will help you pick the right width and length.
Fitting tips that make a cover last longer
1. Tape the frame first. Where polythene touches the steel hoops, the metal heats up in the sun and weakens the film. A 3 mm foam Anti Hotspot Tape creates a thermal barrier between frame and cover — and its low-friction surface makes it easier to pull the sheet over the frame. It also pads rough edges and bolts that could tear the film.
2. Choose a calm day. Never try to fit a cover in the wind — even a light breeze turns a large sheet into a sail. Many growers prefer a warm day, when the film is more flexible and easier to pull tight.
3. Pull it tight and even. A slack cover flaps in the wind, and constant flapping is what wears polythene out fastest. Work from the centre towards the ends.
4. Keep a roll of repair tape. Small tears are easy to fix before they grow. A UV-stabilised clear Polythene Repair Tape sticks even in cold, damp conditions (working range −30°C to +80°C) — clean and dry the area, then apply the tape over the tear.
Frequently asked questions
How long does a polytunnel cover last?
It depends on the UV rating and how exposed the site is. Our 720 gauge UV4 film is designed for a minimum of 4 seasons, the 900 gauge UV10 film for a minimum of 10.
Can I order a custom length?
Yes — the film is cut to the length you choose, from 2 m. Maximum lengths depend on the width; for longer runs, contact us about collection.
Is thicker always better?
Thicker film is more resistant to tears and punctures and is rated for longer, but 720 gauge is still a sound choice for sheltered gardens and smaller tunnels.
Do you deliver?
Yes — polytunnel covers come with free nationwide delivery in Ireland.
Ready to re-cover your tunnel?
Browse our 720 gauge UV4 and 900 gauge UV10 polytunnel covers, add Anti Hotspot Tape for the frame and a roll of Repair Tape for peace of mind.