Double Glazed Window Repairs Over time, double glazing can cause problems, such as a fog between glass or a decaying frame. These are easily fixed and can be less expensive than you think. Contact the company from which you purchased it to see whether there is a guarantee. It's also worth trying to fix any issues yourself before you call a professional. Sealing Window seals (also known as upvc window repair seals) play an important part in the insulation of double glazed window repairs-glazed windows. Incorrect seals can cause drafts, condensation and other issues. Seals that are damaged may be repaired or even replaced to restore the efficiency of your double glazing. The most common sign that double-glazed windows require sealing is the possibility of water leaking between the glass panes. The moisture could cause stains, harm the frames of the windows, and also increase the cost of energy.