Window Lintel Failure: Signs, Repair & Prevention

Windows in your home do more than just let in light and let you see outside; they are also an important part of the building. The window lintel is an important part of a brick or masonry house that people often forget about. It is above each window opening. This beam supports the wall above it, which keeps your window frames and the whole building safe and stable for years to come.

In this complete guide, we’ll go over everything a homeowner needs to know about window lintels, including what they are, what materials they are made of, how to tell if one is broken, and why it’s always best to hire a professional to inspect and fix them.

The structural purpose of a window lintel

A lintel is a horizontal beam that goes over a door or window opening in a wall. The only thing it does is move the heavy bricks or masonry above the opening to the solid walls on either side. If the lintel doesn’t work, all of the weight will go straight to the window frame. This will cause the frame to bend and break, which will cause much worse and more expensive structural damage. This way of spreading the load is a basic rule of construction that has been used for hundreds of years, from ancient stone buildings to modern skyscrapers.

A brief history of lintels in architecture

People have been using the post-and-lintel system for a long time. The first examples, like Stonehenge, show a simple but effective way to use a horizontal stone beam (the lintel) on top of two vertical posts. As building techniques got better, so did the design and materials used for lintels.

• Ancient civilizations: The Egyptians and Greeks built grand temples with stone lintels, which they often used to make decorative facades.
• Roman engineering: While the Romans were famous for their use of arches, they still relied on lintels for many door and window openings, often adding carvings and inscriptions.
• Medieval and Renaissance: The rise of the arch for larger spans didn’t eliminate the lintel. Architects of the Renaissance revived classical styles, bringing back ornate, decorated lintels for windows and doorways in palaces and public buildings.
• The Victorian era: In the Victorian era, a decorative flat horizontal row of bricks, known as a ‘soldier arch,’ became common. Unfortunately, these often lacked sufficient support, leading to masonry issues over time.
• Modern construction: Today, advanced materials like steel and reinforced concrete have made lintels more robust, allowing for wider openings and heavier loads while meeting modern building codes.

A closer look at lintel materials

Different types of construction require different lintel materials. The choice depends on the load requirements, aesthetics, and overall budget.

• Steel Lintels:
  • Pros: Excellent strength-to-size ratio, ideal for spanning wide openings, and can bear heavy loads. Modern steel lintels are often galvanized to resist corrosion.
  • Cons: Susceptible to rust if not properly protected, and corrosion can cause the metal to expand and crack the surrounding masonry.
• Reinforced Concrete Lintels:
  • Pros: Highly durable, fire-resistant, and cost-effective. The steel reinforcing bars add tensile strength to the concrete’s natural compressive strength.
  • Cons: They are Heavier and more difficult to install than steel, and they can crack if not properly installed.
• Timber Lintels:
  • Pros: Traditional, with a natural aesthetic, and often used in heritage structures.
  • Cons: Vulnerable to rot, moisture damage, and wood-boring insects. Modern building codes often require additional reinforcement for timber lintels, particularly in load-bearing situations.
• Brick and Stone Lintels:
  • Pros: Aesthetically appealing, they blend seamlessly with existing masonry.
  • Cons: Traditional brick lintels are only suitable for smaller openings and lighter loads unless reinforced. Stone lintels are durable but heavy and can be prone to cracking under vibratory stress.

6 warning signs of a failing window lintel

A failing lintel can pose a serious threat to your home’s structural integrity and safety. Catching the signs early can prevent more extensive and costly repairs.

1. Diagonal Cracks: The most common sign of a failing lintel is the appearance of vertical or diagonal “stair-step” cracks in the masonry radiating from the top corners of the window opening. These cracks occur as the lintel sags, causing the wall above to settle and crack.
2. Sagging or Bowing Masonry: Look for visibly sagging or bowing bricks or masonry directly above the window opening. This is a clear indication that the lintel is weakening and struggling to support the load.
3. Rust Stains: If your home has steel lintels, watch for orange or brown rust streaks on the masonry below the window. This signifies that the lintel is corroding, expanding as it does, and pushing the surrounding brickwork apart.
4. Difficulty with Window Operation: If your window becomes hard to open or close, or if the frame appears distorted or out of alignment, it could be a sign that the lintel is shifting and putting pressure on the frame.
5. Gaps Between the Frame and Wall: A visible gap where the lintel and window frame meet is a sign of structural movement. This can allow moisture and pests to enter the wall cavity, leading to further damage.
6. Crumbled Mortar or Crushed Bricks: Failing lintels exert immense pressure on the wall, which can cause the mortar joints to crumble or the bricks in the corners to chip and crack.

Why professional assessment and repair are crucial

If you see any of these warning signs, you should call a qualified professional, like a structural engineer or masonry contractor, to get a full evaluation. Trying to fix a structural part like a lintel yourself can be risky and cause bigger, more expensive problems later on.

• Expert Diagnosis: Professionals can accurately diagnose the cause and extent of the damage, which might be more complex than it appears. They can determine if the issue is a simple repair or requires a full replacement.
• Safety First: Lintel repair involves temporarily supporting the wall and working with heavy materials, which requires specialized tools and expertise. A professional ensures the work is done safely and according to proper procedures.
• Long-Term Solution: Qualified contractors perform a long-term repair using high-quality materials and techniques. For example, reinforcing a failing brick lintel with helical bars or installing a properly protected galvanized steel lintel ensures lasting structural stability.
• Code Compliance: Structural modifications like lintel replacement or repair must adhere to local building codes. A professional will ensure the work is compliant, preventing legal complications and guaranteeing safety.

Conclusion: A small price for peace of mind

Window lintels might not be the most beautiful part of your home, but they are very important for keeping it strong. It’s worth the small cost of having your home checked regularly, especially if it’s older or you’ve just replaced the windows, to avoid the stress and cost of major repairs later on. You can keep your home safe, sound, and beautiful for many years by learning how things work, spotting the signs of failure, and trusting professionals like HTCR to check and fix things.