How to Detect and Fix Curtainwall Leaks [2024 Guide]

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Have you noticed water dripping down the inside of your building’s glass facade? Those pesky curtainwall leaks can be tricky to track down. But with new leak detection tools and curtainwall repair techniques, it’s now easier than ever to stop those leaks in their tracks.

In this article, we’ll walk you through the latest methods for sniffing out those curtainwall leaks.

But first, do you know what makes a curtain wall unique? Understanding the concept behind curtain walls will help you make informed decisions about the best approach to fixing them — repairs or replacement.

What Is a Curtain Wall System?

Curtain wall refers to the lightweight exterior cladding systems for buildings. It’s a non-structural cladding system that hangs from the edge of the building floor slabs and is commonly found in high-rise industrial buildings. The curtain wall design is made of aluminium frames, metal panels, supporting glass panels and other lightweight materials.

Here are various unique benefits of installing curtain walls:

Curtain Wall Systems

Facade and Glazing

The main purpose of a curtain wall is to protect the external walls of the building from outside elements while letting in natural light. Curtain walls are often used as a facade for glass architecture designs. For example, a shadow box construction creates a perception of depth behind the glass. The glass panels in a curtain wall system allow transparency and daylighting.

Anchorage and Support

Curtain walling systems are anchored to the edge of a building’s floor slab using anchors. With thin aluminum sheets sandwiching the panels, they are designed to be self-supporting and transfer wind loads to the main building structure. The curtain wall frames span vertically and horizontally between floors, holding infill panels like glass in place.

Sealing and Weather Resistance

The design of curtain wall systems involves placing gaskets and sealants between the aluminium frames and glass panels, helping to prevent air and water infiltration. They are installed to withstand weather elements like rain, snow, and wind.

The main benefits of curtain wall framing are natural lighting and a shield from the elements. However, curtain walls also require periodic maintenance and repair to fix any damaged components. So, if you’re experiencing leaks in your curtain wall system, don’t fret; by understanding how to detect such leaks, you can take active steps towards fixing them.

Detecting Leaks in Curtain Wall Systems

When water starts seeping into your building through the glass curtain wall, you know maintenance is necessary. The earlier you detect leaks, the less damage they’ll cause.

There are a few tried-and-true methods for finding leaks in curtain wall systems, including the following:

  1. Visual inspection
  2. Water testing
  3. Moisture metres

1. Visual Inspection

A visual inspection of the interior and exterior of the curtain wall is a good first step.

Look for signs of water damage like stains, mould, or peeling paint. Check that sealants and gaskets are intact and that there are no cracks or holes in the curtain wall.

Pay extra attention to penetrations or transitions. Binoculars or a camera with a zoom lens can help inspect hard-to-reach areas.

2. Water Testing

Spray-rack and hand-nozzle testing involve spraying water onto the curtainwall under controlled conditions to pinpoint leak paths. These tests, outlined in AAMA 501.2 and ASTM E1105, check that your curtain wall meets performance standards. Non-destructive infrared thermography can also detect leaks by revealing thermal bridges in the curtain wall.

3. Moisture Metres

Moisture metres measure the amount of water in building materials. Placing moisture metres against the interior of a curtain wall can indicate areas of increased moisture that may point to leaks. Moisture metres can detect leaks even in materials that don’t show visible water damage. However, they may give false indications, so further testing is recommended.

Once you’ve detected the leaks in your curtain wall system, it’s time to make repairs or replacements to prevent damage. But before we delve into that, it’s important to identify the most likely triggers of curtain wall leaks.

Common Causes of Curtain Wall Leaks

Knowing why you experience leaks in curtain walls will both help you to fix them, and as well prevent future leaks.

Here are some common culprits:

  1. Missing or improperly applied sealants
  2. Faulty or missing flashings
  3. Weep holes issues
  4. Condensation build-up 

1. Missing or Improperly Applied Sealants

The sealants used in curtain wall systems, like silicone or polyurethane, prevent water from seeping into joints and seams. When these sealants start to break down or are improperly applied, water can infiltrate the system. To avoid leaks, it’s a good idea to have your curtain wall sealants inspected regularly to spot areas of weakness.

2. Faulty or Missing Flashings

Flashings redirect water away from joints and seams in the curtainwall. When flashings are damaged, incorrectly installed, or missing altogether, water can freely seep into the system. Flashings should be closely examined during regular curtain wall inspections, and repairs or replacements should be made as needed.

3. Weep Holes Issues

Weep holes allow for drainage and ventilation in curtain wall systems. If weep holes become clogged or are improperly sized or positioned, water cannot drain effectively and will build up behind the curtain wall, eventually leading to leaks. Weep holes should be clear and unobstructed to prevent water buildup.

4. Condensation Build-Up

In some cases, condensation forming on the interior side of the curtain wall can lead to water infiltration issues. This often happens when there is improper vapour barrier installation or ventilation in the building. Condensation build-up should be addressed to avoid long-term damage to the curtain wall system and other building components.

Condensation Build-Up

Following a regular inspection and maintenance schedule for your curtain walling installation helps you detect these common issues early and avoid costly water damage and repairs. But once the damage has been done, knowing how to repair it is key to ensuring proper function. While you can easily fix some minor damage, you will need a professional glazier for most curtain wall repairs — more details below!

Repairing and Replacing Curtain Walling Sections

Over time, leaks can develop around the edges of your office buildings’ glass panels. If left unaddressed, these leaks allow water to seep into the building, damaging interior finishes and structural elements.

Here are some common repair techniques for curtain wall leaks:

  1. Seal and repair
  2. Panel replacement
  3. Structural assessment

1. Seal and Repair

For minor leaks around panel edges or seams, sealant or repair tape may be adequate fixes. The sealant comes in clear or matching colours and can be applied directly to gaps around the glass perimeter or at panel joints.

Repair tape is also available in a range of colours to match your curtain wall and can patch small tears or holes in the panels themselves. These are easy, cost-effective solutions, but they may only provide temporary relief before more substantial repairs are needed.

2. Panel Replacement

If leaks have damaged curtainwall panels or are too large to patch, full panel replacement may be required. Individual panels can be removed, and new ones installed to match your existing curtain wall system. This preserves the overall look of your building facade while fixing any issues. Panel replacement does require scaffolding for access and you’ll need the services of an expert glazier to handle such repairs.

3. Structural Assessment

For persistent or severe leaks, it may be necessary to evaluate the curtain wall structure itself. The aluminium frames and anchors that support the glass panels can become damaged or corroded over time, exposing them to water. A structural assessment will determine if any parts of the curtain wall system need repair or replacement to properly support new sealant, panels, or glass. Repairs at this level aim to provide a long-term solution and prevent future water damage.

Structural Assessment

Implementing the right solutions based on the severity of issues will keep your building facade—and everything inside—safe and dry for years to come. However, you need the right glazing contractor to ensure each repair is properly done.

Choosing the Right Curtain Walling Contractors for Your Project

When it comes time to repair or replace your building’s curtainwall system, selecting a qualified contractor is crucial. As a building owner, you want a team with experience handling projects of similar scale and complexity.

Here are some considerations to look into:

Certified and Insured

Make sure any contractor you consider is properly certified, licensed, and insured to work on commercial curtainwall systems. Curtainwall installation and repair are technical jobs that require expertise. Don’t take chances with uncertified contractors to save money — it’s not worth the risk.

Experience With Your Curtainwall Type

Whether you have a unitised or stick curtain wall system, choose a contractor experienced with your specific type. Unitised curtain wall systems require highly specialised skills to install and repair. Stick curtain walls also need experienced technicians to replace seals, gaskets, and other components while maintaining performance.

Timely and Cost-Effective Solutions

Evaluate potential contractors based on their ability to provide solutions that meet your timeline and budget needs. Curtainwall repair and replacement projects can be complex, but an experienced contractor will give you a realistic estimate of costs and duration. They can also suggest ways to contain costs when possible, such as partial refurbishment of components in good condition.

Choosing the right curtainwall contractor for your building is a big decision. Do your due diligence, get references from past clients, and don’t just go with the lowest bid.

A reputable contractor experienced in commercial curtainwalls will ensure your project is handled properly, providing lasting value and peace of mind. At GLRE, we are certified and accredited by multiple agencies to provide quality curtain wall refurbishment services for UK businesses. Contact us today to learn more.

Frequently Asked Questions

What is the concept of curtain walling?

Curtain walling is an external building facade system; it’s non-structural and made of lightweight materials, which reduces construction costs. Its main purpose is to shield the interior from the elements while enabling natural light to illuminate the building, creating an airy and inviting space.

What is the difference between cladding and curtain walling?

Cladding and curtain walling are both external coverings, but they differ in function and form. Cladding is typically a layer of protection and aesthetic appeal, made from various materials like wood, metal, or PVCu. Curtain walling, on the other hand, is usually a glazed aluminium frame system designed to let in light and resist the weather.

Is curtain walling expensive?

Curtain walling can be more costly upfront due to its sophisticated design, which aims to minimise water penetration and air leakage. However, the investment often pays off by reducing the risk of leaks and long-term maintenance costs, owing to fewer exposed parts and simpler structural connections.

What are the three types of curtain walls?

The 3 main types of curtain walls are:

  • The stick curtain wall system: The components are assembled piece by piece on-site.
  • The unitised curtain wall system: This is pre-assembled in panels and installed as a single unit.
  • The semi-unitized curtain wall: This combines both the stick and unitised wall system methods.


Curtainwall leaks may seem daunting, but with the right detection methods and repair solutions, you can tackle them. Don’t let a leaky curtainwall negatively impact your building’s performance and appearance. Be proactive, inspect regularly, and act quickly when issues arise.

With today’s leak detection tools and sealants, you don’t have to spend a fortune on repairs. Just make sure to employ the services of a certified glazing refurbishment company. Contact us now at GLRE to discuss your curtainwall project needs!

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