How to repair a roller fly screen: spring, mesh and guides

What you need

• Phillips and flat screwdrivers
• Long nose pliers
• Craft knife and metal ruler
• Scissors
• Vacuum cleaner with brush
• Tape measure and marker
• Work gloves
• Made to measure fibreglass fly screen mesh (Leroy Merlin, Bricodepot)
• Retaining cord or spline for the mesh, if the model uses one
• Silicone spray or paraffin wax for the guides
• Self-adhesive fly screen patch for small holes
• Replacement stop or end cap for the end bar, if one is missing

Step by step

1. 1

   Identify the fault

   Extend and retract the fly screen slowly. If it does not wind in fully, it is the spring. If it rubs or jams, it is the guides. If you can see light through a spot, look at the mesh. Note the symptom before taking anything apart.

2. 2

   Clean the guides

   Vacuum the inside of both guides with the brush. Wipe with a cloth with water and soap, dry and apply silicone spray. If a guide is bent, straighten the section by hand or with pliers protected with a cloth.

3. 3

   Hold the tube before you touch it

   With the mesh wound in, find the side cap of the cassette. Remove its screws and hold the tube with one hand so it cannot turn. A loose tube with the spring under tension will knock your fingers.

4. 4

   Re-tension the spring

   With the tube held, turn it 4 to 8 times in the direction the mesh winds and put the cap or the pin back. Test it. If it does not wind in fully, add a turn. If it snaps in hard, take one off.

5. 5

   Remove the damaged mesh

   Extend the fly screen, remove the stop from the end bar and release the mesh from the bar. Then take the mesh off the tube; it is nearly always held with a cord or spline in a groove. Note the real width and height.

6. 6

   Cut the new mesh

   Lay the new mesh on a table. Cut the width of the old one and 3-4 cm extra on the length, with a craft knife and metal ruler. Cut straight, so it does not wrinkle when it winds.

7. 7

   Fix the mesh to the tube and the bar

   Push the edge of the mesh into the groove of the tube with the cord or spline, tensioning evenly on both sides. Do the same on the end bar. The mesh should be centred and free of creases.

8. 8

   Wind on with tension and refit

   Wind the mesh onto the tube by hand with gentle tension and put the tube back in the cassette. Re-tension the spring with 4-6 turns and fit the cap.

9. 9

   Test the travel

   Pull the bar all the way to the stop and let it go slowly. The mesh should wind in without a bang or creases. Trim any excess mesh that sticks out and fit the end bar stops.

10. 10

    Protect against salt air

    Apply a drop of silicone spray to the guides and wipe off the excess. Repeat once a year, and rinse with fresh water if the fly screen is exposed to the sea.

How a roller fly screen works and what usually goes wrong

A roller fly screen has a cassette fixed at the top or side of the opening, an inner tube with a torsion spring, the mesh wound onto the tube, two aluminium side guides and an end bar with a pull handle. When you pull the bar, the mesh unrolls along the guides. When you let go, the spring turns the tube and winds the mesh back in.

There are four common faults: the spring loses tension and the mesh does not wind in fully, the guides collect dust, sand or hair and the bar sticks, the mesh tears from a tug or from a pet, and the end bar drops or slips out of the guide. Each one has a different fix, and only in a few cases do you need to replace the whole screen.

In coastal homes you add salt air, which dries out the lubricant, and sun, which makes plastic mesh brittle. A fly screen that has been on a seafront terrace for more than eight or ten years usually has every component worn, and replacing it makes more sense than repairing it.

Common mistakes when repairing a roller fly screen

• Letting go of the tube without holding it. The spring is under tension. If you let go suddenly, it spins, knocks and can hurt your fingers. Always hold the tube before taking off the cap.
• Over-tensioning the spring. With too many turns, the mesh snaps in, hits the guide and tears sooner. Count the turns and add one at a time.
• Using oil or grease in the guides. It attracts dust and sand and within two weeks it is worse. Use silicone spray or paraffin wax.
• Cutting the mesh by eye. If it is short, it will not reach the stop. If it is too wide, it wrinkles and jams. Cut 3-4 cm extra on the length and trim after fitting.
• Using any old mesh. Fly screen mesh is fibreglass coated with PVC, or polyester. Chicken wire or net curtain is weak and tangles in the spring.
• Overtightening the cassette screws in an aluminium frame. The guide distorts and the bar stops sliding well. Tighten just enough.
• Repairing with silicone or duct tape. It lasts a week and leaves the mesh stiff; it ends up tearing at that point. For small holes, use self-adhesive fly screen patches.

When it is better to replace the whole fly screen

Replace the fly screen if the spring has broken and the cassette is thin plastic, if the guides are warped from a knock, if the mesh is faded and crumbles when you touch it, or if the cassette no longer fixes firmly to the frame. In those cases a replacement cassette costs almost as much as a new fly screen.

A mesh replacement costs €25-45 with Manitas Costa. A new roller fly screen fitted costs €75-130. If yours is more than ten years old, it is worth comparing. Choose a model with aluminium guides and a profiled cassette, not a plastic one; the budget products from Leroy Merlin or Bricodepot do not usually survive a summer of daily use.

If what you want is to put up a new one without drilling the frame, there is no-drill fly screens. To choose between roller, sliding and pleated, see types of fly screens.

When to call a professional

Call us if the spring is broken, if the fly screen is a large one (a balcony or terrace door), if the guide is curved or if you cannot find mesh of the exact width. Also when the screen is on a third or fourth floor and the repair means leaning out of an open window.

A mesh replacement costs €25-45. A roller fly screen fitted costs €75-130. A pleated one costs €160-260. For a complete two bedroom flat, between €320 and €480. If you need several windows repaired, we quote the whole visit from a photo at a fixed price.

You will find more in made to measure fly screens with fitting and in how much fly screens cost. For everyday upkeep, see how to clean fly screens.

Coastal climate: salt air, sun and the levante wind

In Torrevieja, Benidorm, Dénia or Jávea, fly screens have three enemies: salt air that corrodes the screws and springs, sun that dries out the mesh, and strong wind that tugs at the bar when it is left open. Close the fly screen on stormy days and do not leave it extended with the window open.

Clean the guides with a vacuum cleaner and brush every two or three months in summer and every six in winter. A drop of silicone spray once a year keeps it sliding. If the fly screen is on a terrace facing the sea, rinse it with fresh water once a month to remove the salt.

If you manage a holiday let in Torrevieja, Benidorm or Alicante, go over the fly screens before each season: guests notice this detail straight away.