Double Glazing Installation

All you need to know about resealing double-glazed windows

Posted by | March 19, 2021

Resealing your windows helps you seal in the warmth 
Double-glazing does a great job of keeping your home comfortable and secure. But as time passes aging windows will begin to show signs of wear and tear. One of the critical areas of double-glazed windows and doors that begins to fail over time is the sealing. In this concise guide, we will show you:

how to recognize problems with the seal on your double-glazing,
how to know if a failed window seal can be fixed,
how to repair a double-glazing window seal.

What is a window seal?
The seal on your window is a rubber gasket that is tightly fitted between the glass panels and the uPVC window pane. The seal spans the inner perimeter of the frame and forms an air-tight seal which is integral to maintaining the gas-filled air space between the two panes of glass that make up the window. Additionally, an outer sealant layer fills the space between the glass and the frame. Window seals are therefore critical to the insulative benefit that double glazing delivers, and it is no surprise that problems or frank failure of the seal will lead to a significant deterioration in the performance of your windows.

What causes a window seal to fail?
The stage at which the seal failure occurs usually indicates the underlying cause.

  • If a window seal is found to have failed soon after the installation of double-glazing, the window is likely to be carrying a manufacturing defect or problems with how the windows have been installed.
  • Problems with the frames, including structural damage and warping, can increase the likelihood of the seal becoming punctured or failing. This can happen if paintwork is being stripped with a heat gun nearby the windows or property renovation work is taking place nearby. Even pressure washing of the windows can cause this damage.
  • Moisture build-up on the window over time can lead to the growth of mold that can erode the seal.
  • The seasonal cycles of hot and cold temperatures cause materials in your property to repeatedly expand and contract. Over time, this wears the seal down to a point, late in the life span of the window, where it fails.

What are the signs your windows need resealing?
With the seal gone, you not only lose the insulative layer or inert gas that sits between the pains, but the window also loses its protection against the ingress of dust, dirt, and moisture. You will begin to see condensation or persistent fog developing on the inside of the glass pains and dispensing n the extent of the damage to the seal, dirt may track into the gap as well. The windows may also become draughty (heat escaping to the outside) and a cooler part of the room relative to the surrounding walls.

These problems indicate that you will need to repair your window seal.

What are the options for repairing a double glazing window seal?
A failed seal should not be neglected as the problem only gets more extensive with time. Here are your main options.

  1. Attempt a DIY repair: The options available to the DIYer are limited to strategies to tackle the ingress of moisture and air by reinforcing the sealing of the window pane externally with caulking, or lengths self-adhesive rubber seals that can be applied to the junction between the glass and the frame. This may offer some short-term relief but at best only defers the problem.
  2. Obtain a professional repair of your window seal: Many double-glazing companies will be pleased to visit your property to tackle a broken seal. Professionals can not only reseal the window but also tackle the unsightly condensation build-up between the panes to refresh your view. It is always worth checking the paperwork for your windows to see if they are still in warranty as the manufacturer and company who installed them may be able to remedy the problem without additional expense.
  3. Replace your double-glazing: Even with the best efforts at repair, a failed seal is likely to recur as the window generally ages. It may be time to get new windows, especially if you are experiencing significant draughts and a rise in energy bills.

Draughty windows with a failed seal? Talk to us!
Our tradesmen have a wealth of experience with double glazing problems great and small. Simply call or email our helpful team to arrange a visit to your property, at a time of your convenience, to take a look at your windows and see what can be done.