Does the lower part of your patio door look cloudy or covered in fine lines where your dog waits to go outside? Before replacing a glazed panel, it is worth identifying whether the marks are actually in the glass, on a coating, or simply stubborn residue. The right answer depends on the surface and the depth of the damage.
Can a dog scratch glass?
Ordinary dog claws are generally softer than standard window glass, so claws alone do not usually cut deep grooves into an intact glass surface. However, grit or sand trapped against a paw, collar or cleaning cloth can abrade glass. Repeated contact may also leave deposits or damage a surface-applied film or coating. The fact that marks sit at paw height does not prove what caused them.
First, check what the marks really are
In daylight, look at the glass from several angles, both straight on and from the side. If safe and accessible, gently clean a small area with a suitable glass cleaner and a clean, soft microfibre cloth. Avoid dry rubbing, abrasive pads, blades, toothpaste or DIY polishing compounds. They can make the problem worse, especially on coated or filmed glass.
If the lines disappear when the area is clean, the issue may have been residue rather than scratched glass. If they remain visible in changing light, they may be scratches or coating damage. A fingernail catching on a mark can suggest greater depth, but it is not a definitive test and is no substitute for an inspection.
Can professional polishing remove the scratches?
Some shallow scratches on suitable uncoated glass can be reduced or removed using specialist glass-polishing equipment. The technician needs to assess the glass type, damage depth, position and the amount of material that would need removing. Deeper scratches are not always practical to remove: aggressive polishing can create visible distortion or an uneven reflection.
Modern patio and bifold doors may have toughened or laminated glazing, insulating glass units, low-emissivity coatings or applied window film. A coating or film cannot be treated as though it were plain glass. Polishing may damage the finish or leave an obvious patch, and some surfaces should not be polished at all. See our related guide to telling scratched window film from scratched glass.
When is replacement the better choice?
Replacement or a glazing specialist’s advice may be more appropriate where a pane is cracked, chipped at a vulnerable edge, heavily damaged, or where the marks are in a specialist coating. Deep damage close to seals, frames or edges can also limit safe access for polishing. A professional should not promise a flawless result before seeing the panel.
For more general guidance, read our article about scratches on patio and sliding door glass and how scratch depth affects repair suitability.
How to send photos for a useful assessment
For a first assessment, send one photograph of the entire door, one close-up with the marks visible in angled daylight, and a short video moving slowly across the surface. Mention whether the marks are on the room-facing or outside face, whether there is any tint or film, and the approximate size of the damaged area. Please include your postcode. Do not attempt to peel off film or scrape the marks to test them.
Local glass scratch assessments
Elite Glass Restoration considers suitable glass scratch-removal enquiries in and around Gerrards Cross, Beaconsfield, Farnham Royal, Windsor, Ascot, Virginia Water and nearby parts of Buckinghamshire, Berkshire and Surrey. Not every panel can be polished, and suitability is confirmed from the damage and glass specification rather than from photos alone.
Have marks at paw height on a patio or bifold door? Contact Elite Glass Restoration with clear photos or a short video and your postcode for an initial suitability assessment. We will explain whether a closer inspection is worthwhile.