Double Glazed Window Repairs Double glazing can develop problems over time, such as a mist between the glass or rotting frames. These problems are simple to fix and can be less expensive than you expected. Contact the company from which you purchased the item to determine if there is a warranty. It's worthwhile to try fixing any issues yourself first. Sealing window repairs seals, also known as uPVC window seals, play an an important role in the insulation of double-glazed windows. Insufficient seals can cause condensation, drafts and other issues. Fortunately damaged seals can be repaired or replaced to restore the efficiency of your double glazing. The most common sign that double-glazed windows need to be resealed is the possibility of water leaking between the glass panes. This can cause stains, damage to the window repairs frames, and raise your energy bills.