What Is a Top Hung Window | Complete Guide 2025

A top hung window is a type of casement window where the hinges are fixed at the top, and the sash opens outward from the bottom. The window swings outward to create ventilation while keeping the interior protected from rain and dust.

Top hung windows are commonly used in:

• Bathrooms

• Staircases

• Kitchens

• Utility areas

• High-rise buildings

Unlike side-hung windows, which open horizontally, top hung windows open vertically, allowing consistent airflow without compromising privacy or security.

How Top Hung Windows Work

• Opening Mechanism Explained

The sash is fixed with top-mounted friction hinges. When operated through the handle, the bottom of the sash pushes outward while the top remains anchored.

• Role of Friction Hinges

The friction hinge:

• Supports the sash weight

• Controls smooth outward movement

• Allows adjustable ventilation angles

• Holds the sash open without additional stays

• Limitation Stays & Safety Features

Some top hung systems include limitation stays that:

• Restrict maximum opening angle

• Improve wind resistance

• Enhance child safety in high-rise installations

Top hung windows allow controlled airflow, prevent water ingress during rain, and maintain an outward ventilation pattern.

Benefits of Using Top Hung Windows

• Weather Protection

The outward slant acts as a shield during rain, allowing ventilation without letting water enter.

• Safety Advantages

No inward swing ideal for areas with movement, such as corridors and staircases.

• Low Maintenance

Minimal moving parts lead to reduced wear and longer system life.

• Suitable for High-Rise Buildings

Top hung windows maintain high resistance against strong winds and pressure loads.

Additional Advantages:

• Excellent privacy due to limited outward projection

• Efficient cross-ventilation

• Strong sealing performance when closed

• Compatible with multi-point locking systems

Technical Components of Top Hung Systems

• Friction Hinges

Available in various sizes such as 8", 10", 12", and 14".
Key specifications include:

• Stainless steel grade

• Load capacity

• Opening angle range (typically 30–60 degrees)

• Handle Types

Common handle systems include:

• Espagnolette handles

• Cockspur handles

• Push-lock handles

Each provides secure locking and smooth operation when paired with the correct gearing.

• Gaskets & Seals

EPDM or TPE seals ensure:

• Air-tightness

• Water-tightness

• Dust resistance

• Reinforcement Inside the Sash

Metal reinforcement (1.0–1.5 mm thick) is critical for structural integrity, especially in uPVC profiles.

Additional Technical Elements:

• Multi-point locking system

• Glazing beads

• Drainage channels

• Weather seals

Materials Used in Top Hung Windows

• uPVC

Known for:

• High energy efficiency

• Corrosion resistance

• Strong sealing properties

• Low maintenance

• Aluminium

Preferred for:

• Slim, modern profiles

• High structural strength

• Excellent durability

• Better performance in large window sizes

• Steel / Hybrid Systems

Used in special applications requiring high fire resistance or industrial-grade performance.

Each material offers different benefits depending on the building type, climate, and aesthetic requirements.

Ideal Applications for Top Hung Windows

• Bathrooms

Provides privacy, moisture ventilation, and protection from rain.

• Staircases

Safe, secure, and does not intrude into movement areas.

• Kitchens

Allows heat and smoke to exit efficiently.

• High-Rise & Commercial Projects

Top hung systems offer stability in strong wind pressure zones.

Additional Suitable Areas:

• School buildings

• Hospitals

• Corridor windows

• Utility rooms

Top hung windows are especially effective when the goal is controlled ventilation with minimal risk of water entry.

Common Problems & How to Avoid Them

• Dropped Sash

Mostly caused by improper hinge selection or inaccurate alignment during installation.

Prevention:
Use the correct hinge size based on sash height and weight.

• Hard to Open / Close

Can occur if hinges lack lubrication or if seals compress unevenly.

Prevention:
Lubricate hinges annually and ensure uniform gasket compression.

• Water Leakage

Usually linked to poor frame leveling or insufficient internal drainage.

Prevention:
Maintain correct slope angles and inspect drainage pathways.

• Faulty or Low-Quality Hinges

Inferior hinges reduce performance and lifespan.

Prevention:
Select hinges with minimum Grade 304 stainless steel.

Other Risks & Avoidance:

• Glass misalignment → ensure correct glazing padding

• Over-tightened screws → follow manufacturer torque guidelines

Comparison: Top Hung vs Side Hung vs Awning

Structural Differences

• Top Hung: Opens outward from bottom

• Side Hung: Opens like a door

• Awning: Similar to top hung but with a different hinge design

Ventilation

• Top hung: Best for controlled airflow

• Side hung: Offers maximum ventilation

• Awning: Good airflow with better rain protection

Wind Pressure Resistance

• Top hung systems perform better in high wind zones due to compact opening angles.

Cost

• Side hung: Usually lowest cost

• Top hung: Mid-range

• Awning: Slightly higher due to stronger hinges

Maintenance

• All systems require hinge lubrication and gasket cleaning

• Top hung has fewer mechanical components, lowering maintenance needs

Maintenance Requirements

• Cleaning Schedule

Wipe frames and glass every 2–4 weeks to prevent dust buildup.

• Lubrication of Hinges

Apply silicone spray or light machine oil every 6–12 months.

• Gasket Care

Inspect for cracks and clean with mild soap to maintain elasticity.

• Glass & Frame Cleaning

Use non-abrasive cleaners to avoid damage.

Additional Maintenance Notes:

• Check drainage slots twice a year

• Ensure screws remain tight

• Inspect reinforcement integrity if windows show excessive flex

Conclusion

Top hung windows offer a reliable, durable, and efficient solution for areas requiring controlled ventilation, weather resistance, and safety. Their design makes them ideal for high-rise buildings, bathrooms, kitchens, and other environments where airflow and protection against rain are crucial.

By combining the correct hinge size, appropriate frame material, and proper installation practices, top hung windows deliver excellent long-term performance with minimal maintenance.