Top 5 Ways to Identify Commercial Window Leak Causes

By Bill Spiess, General Manager Brin Glass Service

Is your building experiencing leaks around windows? Do you know how to identify the cause? Determining why your commercial building windows are leaking will help you choose the right corrective solution, and the best partner for repairs.

Most people see a leak around a window and think the window must be the cause. That may be true, but the corrective action needed does not always involve window repairs. Here are five questions to help investigate the leak’s cause and give your glazing partner the information needed to stop the water issue.

First, identify where the water is infiltrating. Take notes, mark the locations and take photos or a video. Ask yourself the following questions: 

Preliminary Assessment

Where do you notice the water leak? And how much water is getting in?

• Is it dripping from above the window frame?
• Is water running down the face of the glass?
• Is water leaking at the bottom of the window frame or at the corners?

What current conditions or recent events may have caused the leak?

• Have there been recent storms?
• Could wind or other events have caused damage?
• Was there a heavy rain event, wind-driven rain or an extended downpour?

Has the window leaked in the past? Has this leak been recurring?

A persistent leak is something for concern. A window that shows a small leak after a heavy wind-driven rain is something to document and monitor. If the leak is persistent, it will need to be fixed. In the meantime, check out Construction Executive’s blog on window upkeep in commercial buildings.

How many windows are leaking?

Is the leak in one window or at numerous locations? This will help identify if there is a pattern or a common deficiency in all windows.

Who installed the windows? Who has serviced the windows in the past?

Knowing whether past repairs were successful may provide for faster, more economical repairs again. If the building is new the repairs may be covered under warranty. If the building is old your glazing partner may be aware of historical repairs made.

Common Causes of Leaks

Answering the above questions will provide your glazing partner the information required to identify the cause of the leak and present the right solution quickly and effectively. Whether the solution involves repair of window conditions, or requires addressing a surrounding condition in the wall, the preliminary information you provide will allow your glazing partner to assess the following conditions:

Common causes of leaks at the top of a window frame

• Old or failed caulking at the perimeter of the window frame
• Lack of flashing at the head – this can be a significant issue due to a poor design or installation, and is commonly found in precast construction
• Head flashing was penetrated with fasteners during window, sheet rock or window treatment installation
• Cracks, holes or deficiencies in the wall above the windows – a qualified masonry or restoration contractor should be contacted to assess and repair wall conditions

Common causes of leaks at intermediate horizontal mullions (the bar between panes of glass in a window)

• Missing water diverter over window
• Failed zone dams in curtain wall (not properly sized or well positioned)
• Improper installation of pressure plates in curtain wall

Common causes of leaks at the intermediate mullions and or sill

• Shrunken exterior gaskets – Shrunken gaskets allow an excessive amount of water into a glazing system which overwhelm its weep system
• Lack of, or improper installation, of sill flashing
• Shrunken thermal breaks
• Failed splice joints at sill
• Weep system not adequate, missing or was caulked closed (typically by someone who does not understand the glazing system and purpose of the weep system)
• Failed primary caulk joint at sill and jambs
• Window frame is below grade and water pooling occurs during heavy rain events

Other Environmental Factors to Question & Answer

Q: Does the building have negative or positive pressure and when?

A: Negative pressure can draw water into the exterior building façade.

Q: How warm is it outside?

A: Building substrates contract during winter, spring and fall which can result in larger gaps in cracks or joints.

Q: Is the leak caused by condensation?

A: The combination of frigid exterior temperatures and high interior humidity levels can lead to condensation forming on exterior window frames. Creating positive pressure, reducing humidity levels and having warm air “wash” the windows can help reduce the risk of condensation.

A qualified glazing contractor will take the leak information you provide and determine which of the causes to further investigate. Once the cause is identified, a proper repair will be presented. Your glazing partner is a reliable source to start the process and will help you to further investigate the problem.

If the windows are the cause of the leak, they can repair them correctly. If surrounding conditions are determined to be the cause they will point you to the right trade partner to correct the issue. If the leaks are complex, numerous and involve multiple trades, you may want to involve a third-party consultant to investigate and provide a plan for the best resolution. For more information on tips about commercial building inspection, check out this article by BOMA.

Learn more about how Brin Glass Company can help you. Contact us today.

#We Show Up #We Bring It #We Do It Right

 

Additional Links & Resources

Learn about Brin Glass Service Solutions

See Brin Glass Service Projects

BOMA: Inspect Your Building’s Envelope Early

Five Tips for Window Maintenance and Upkeep in Commercial Buildings