When a window’s insulated glass unit (IGU) seal fails, it can lead to a variety of issues, from fogged glass to decreased energy efficiency. While replacing the entire window may seem like the only solution, in many cases, you can actually repair the broken seal without having to replace the entire window and frame. In this comprehensive guide, we’ll explore the different types of window seals, the common causes of seal failure, and the various repair options available to homeowners.
Understanding Window Seals
Modern windows feature two or more panes of glass separated by a layer of air or inert gas, such as argon or krypton. This design, known as an insulated glass unit (IGU), is sealed around the edges to keep the insulating layer intact and prevent the infiltration of moisture and air. There are three main types of window seals that can fail over time:
- Silicone caulking or sealants: These are applied around the window frame to create a water-resistant barrier and prevent air leaks.
- Weatherstripping: This is typically placed on the operable parts of a window, such as the sash, to create a tight seal when the window is closed.
- IGU seal: This is the seal that holds the insulating gas between the panes of glass in a double- or triple-glazed window.
Causes of Seal Failure
Window seals can fail for a variety of reasons, including:
- Solar pumping: The repeated expansion and contraction of the glass due to temperature changes can cause the seal to degrade over time, especially in windows that receive a lot of direct sunlight.
- Faulty installation: If the window was not installed properly, with the correct amount of pressure on the glass panes, the seal can fail prematurely.
- House settling: As a home settles over time, the resulting movement can put stress on the window seals and cause them to fail.
- Damage to the sealant material: Exposure to certain chemicals, such as paint strippers, or the use of a heat gun near the window can damage the sealant and lead to seal failure.
Repairing a Broken Window Seal
When a window seal fails, there are several options for repair, depending on the type of seal that is broken and the extent of the damage.
Repairing Silicone Caulking or Sealants
If the silicone caulking or sealant around the window frame has cracked or dried out, this is a relatively simple DIY repair. You’ll need a utility knife or putty knife, silicone sealant, and a soft rag. Follow these steps:
- Use the knife to carefully remove the old, cracked caulking.
- Clean the surface with the soft rag to remove any debris.
- Apply a new bead of silicone sealant, smoothing it out with your finger.
- Allow the sealant to fully cure before closing the window.
Repairing Weatherstripping
If the weatherstripping around an operable window has become worn or damaged, you can replace it with new weatherstripping. This is also a straightforward DIY project:
- Carefully remove the old weatherstripping, using a utility knife or putty knife if necessary.
- Clean the surface where the new weatherstripping will be applied.
- Cut the new weatherstripping to size and apply it, following the manufacturer’s instructions.
- Ensure the weatherstripping creates a tight seal when the window is closed.
Repairing a Broken IGU Seal
When the seal of an insulated glass unit (IGU) fails, it’s a more complex issue that typically requires professional intervention. The most common signs of a broken IGU seal are condensation or fogging between the panes of glass. While it’s possible to attempt a DIY repair, it’s generally not recommended, as it requires specialized tools and equipment to properly remove the moisture and reseal the unit.
A professional glazier or window repair company will typically use the following process to fix a broken IGU seal:
- Remove the sash (the frame that holds the glass panes) from the window.
- Install a valve and pump to remove any moisture between the panes.
- Apply a new sealant to create an airtight seal around the perimeter of the IGU.
- In some cases, they may need to refill the IGU with an inert gas, such as argon or krypton, to restore the insulating properties.
If the IGU is severely damaged or the window is quite old, it may be more cost-effective to replace the entire window unit rather than just the IGU. This can also be an opportunity to upgrade to a more energy-efficient window design.
DIY vs. Professional Window Seal Repair
While it’s possible for a homeowner to tackle some window seal repairs, such as fixing cracked caulking or replacing weatherstripping, it’s generally recommended to leave the more complex IGU seal repairs to the professionals. Here are a few key considerations:
- Expertise and tools: Repairing an IGU seal requires specialized tools and knowledge that most homeowners don’t have. Attempting a DIY repair could lead to further damage or an ineffective seal.
- Warranty considerations: If your windows are still under warranty, attempting a DIY repair may void the warranty, leaving you responsible for the full cost of a replacement.
- Energy efficiency and indoor air quality: Improper window seal repairs can lead to decreased energy efficiency and potential issues with indoor air quality, such as moisture buildup and mold growth.
Ultimately, the decision to attempt a DIY window seal repair or hire a professional will depend on the specific issue, your skill level, and the potential cost savings. For complex IGU seal repairs, it’s generally best to leave the job to the experts to ensure a long-lasting, effective solution.
Cost of Window Seal Repair
The cost of repairing a broken window seal can vary widely depending on the type of seal and the extent of the damage. Here’s a general overview of the costs:
- Silicone caulking or sealant repair: DIY supplies can cost as little as $35, while a professional repair may range from $75 to $250.
- Weatherstripping replacement: DIY materials are inexpensive, typically under $50, while professional installation can cost $100 to $300.
- IGU seal repair: Replacing the entire IGU can range from $100 to $600 or more, depending on the size and quality of the window. Professional defogging and resealing can cost $75 to $250.
- Full window replacement: If the window is beyond repair, a complete replacement can cost $150 to over $1,000, depending on the size, frame material, and energy efficiency features.
It’s important to note that the cost of window seal repair can be influenced by factors such as the size and complexity of the window, the cost of labor in your local area, and whether the work is covered by a warranty. Obtaining multiple quotes from reputable contractors is recommended to ensure you get the best value for your money.