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If your problem’s not fixed by one of the following, drop us a note from our contact page.

During installation, moist room air is trapped between a Gecko pane and the glass. On cold days, especially mornings, this can cause internal misting. The Gecko Pane is still cutting heat loss as intended, so you can either:

  • Ignore it and it will disappear as the day warms, or
  • Wipe it away. To do this, prise out the top or a side of the Gecko Pane with a thin object, wipe condensation, and reinsert the Gecko Pane. On warm days you can even just vent affected panes and leave them to dry (see below).

Droplets that don’t disappear as the day warms will require wiping or venting. Don’t worry, this is straightforward, but it can be time consuming for multi-pane windows.

If droplets return, your window frames may be suffering from penetrating damp due to poor paintwork or putty, or prolonged exposure to condensation.

If the window has very flaky paintwork, missing putty or rot (areas spongy to the touch), consider timely remedial works. Dealing with these issues is not an easy DIY job. If untreated, expensive repairs may be required.

Timber windows should be re-painted at least every 7 years. Failure to do so may lead to rot and expensive repairs.

Even if the paint and putty look fine, check there are no cracks (these let water in) and, crucially, where the putty meets the glass, ensure the paint overlaps the glass by 1-2mm all round. This is an essential sealing measure.

Many painters are unaware that these are crucial to sealing timber windows, which is why you should always check.

Contact us for advice on finding painters or see “How to seal timber window frames” below for guidance and DIY steps.

Gecko Panes are designed to fit quite tightly, to ensure a snug, airtight fit. If they bow slightly along each side, they are still effective. However, if the frame comes away from the glass pane by more than 5mm in the middle of any side, if the sponge surround bulges out at the corners, or you just can’t get the pane in, you can adjust the sponge surround.

These methods can remedy sizing errors of up to 12mm:

  1. Check which dimensions are a problem. If there is significant bowing on the sides, but not the top and bottom, it may just be the sides that need adjustment.
  2. Check the corners of your window frame for obstructions such as a build-up of paint. Try to remove this with a utility (Stanley) knife, kitchen knife, flat head screwdriver or similar. If that’s difficult or impossible (the build-up might be glazing putty), then, while pinching the corner of the sponge surround, cut 1–2mm from the tip off of the sponge corner.
  3. If that doesn’t work, trim the sponge surround. Snip off the top of the sponge surround all the way along both problematic sides. Ragged snipped edges will be hidden when reinstalled. Try to fit the Gecko Pane again.
  4. And if that doesn’t work, remove the sponge surround completely. Snip away the corners of the surround so that each side can be removed separately, then pull it off completely. Do for one side, try to refit, then, if it’s still too big, remove the other side.

Gecko Panes should be snug. If they’re not, they may fall out, or misting/condensation may build up behind them. 

If the Gecko Pane is only slightly too small (i.e. there are no gaps visible between the Gecko Pane’s sponge surround and the window frame that allow the glass pane to be seen), just use the provided adhesive strip to stick the Gecko Pane to the window. To do that:

  1. Remove the Gecko Pane.
  2. Cut two lengths of the adhesive strip, about one third of the length of one of the Gecko Pane’s sides.
  3. Clean the section of frame of the Gecko Pane and the glass that you will stick the strip to thoroughly using an alcohol wipe or something similar.
  4. Dry the area.
  5. Stick each adhesive strip to the top left and top right vertical lengths of the Gecko Pane where the frame will face the glass window pane.
  6. Remove the plastic liner from the strip.
  7. Then, using modest pressure, install the Gecko Pane. The strip is very strong and the pane is very light, so not much pressure is needed – you don’t want to push the glass pane out of the window!

Top tip: You can warm up the adhesive strip with a hair dryer which will aid adhesion.

If the Gecko Pane is significantly too small, there may have been an issue when measuring. To ensure you measure for correct fitting, check out our ‘How To’ guide.

If your frames suffer from penetrating damp, causing persistent droplets between the Gecko and window pane which isn’t remedied by time or venting, your windows will need to be repainted. This is ideally undertaken in the summer when the timber is dry, or moisture can be locked in.

If the paint is very flaky, there are areas of rot, large gaps/cracks to be filled, loose putty or you think the paint might contain lead, check the guidance below and/or consider calling a specialist.

If paintwork is in reasonable condition, either:

Engage a painter (easiest and fastest), but make sure they:

  • Use an appropriate exterior paint such as Leyland Trade Hardwearing or Demidekk Ultimate,
  • Sand the relevant surfaces diligently,
  • Fill any cracks in the paint and putty, especially where the glass meets the exterior frame, replacing putty where necessary, and
  • Overlap the glass by 1-2mm all round, applying primer, undercoat and two coats of topcoat.

You can also repaint the exterior of your windows yourself. To do this:

  • Clean the windows and allow them to dry,
  • Sand the exterior paint and putty lightly (use thick masking tape on the glass to protect it from scratching),
  • Use Zinsser primer as an undercoat,
  • Fill any cracks in the paintwork, especially the putty around the glass and particularly the line where the glass meets the putty,
  • Overpaint with at least two coats of hard-wearing exterior paint, such as Leyland Trade Hardwearing or Demidekk Ultimate, ensuring the paint overlaps the glass by 1-2mm all round.

For even better sealing, you can repaint the interior of the frame where it meets the glass using Zinsser primer, and again overlap glass by 1-2mm (this will be hidden by the Gecko Pane).

Windows should be repainted at least every 7 years, ideally every 5, but if water builds up behind your Gecko Panes, repainting is probably needed.

Gecko Panes are designed to fit behind most window furniture, but occasionally there may not be enough space. Finger pulls or handles can often be gently bent outwards to create more room, but caution should be exercised to avoid damaging the window.

Even if a Gecko Pane seems like it will just fit behind an existing closer, it’s important to check that the window can still open and close properly after installation. If the Gecko Pane is too tight against the closer, preventing it from opening and closing fully, it can sometimes hinder the window’s functionality.

Minimum required space: 11mm:


The most common obstruction encountered is sash closers. If there’s less than 11mm of space behind one, and the closer is in good condition, repositioning it can be a relatively straightforward task.

If window furniture that needs to be moved or removed has been painted over, it may require cutting or drilling to extract. Often the original piece can be reused, alternatively, we offer replacement pieces in our shop.

The replacement furniture from our shop are all slimline products, which will only use the smallest space possible, to allow sufficient space for the Gecko Pane.

Step-by-step guide:

In the first instance, scrape away any paint covering screws using a screwdriver or scraper, to determine if they can be removed conventionally. However, screws often become too rusted to remove.

Try to use a screwdriver to remove the original fixings. If this is not possible, you will have to remove the screw heads. This is easiest done with a Dremel.

If you’ve relocated the window furniture to a different position, prepare the initial location by sanding it, filling any gaps with wood filler, and applying a fresh coat of paint to reseal the wooden window surface.