Essential Drainage for Aluminum Windows & Doors

Discover why proper drainage is crucial for the long-term success of aluminum window and door installations in the UAE's challenging climate. Learn how to prevent mold and system failure. aluminum window

London arch almn

2/22/20262 min read

The Basics: How Aluminium Systems Manage Water

Every system is designed on the rainscreen principle, assuming some water will get past the outer seal.

The Zone: Water collects in a carefully engineered cavity between the outer rain deflector and the inner airtight seal.
The Exit: Water is expelled through defined paths to the exterior.

Two Primary Configurations:

Face Drainage: Water exits through visible slots on the front of the frame.
Concealed (Secret) Drainage: Water exits through the bottom into a sub-sill for a cleaner look. For example, the Cortizo COR 70 Hidden Sash uses this to maintain luxury aesthetics.

Why Dubai Makes Drainage Critical

Systems designed for gentle European rain often fail under Gulf conditions:

Intense Storms: Dubai can see 30–50mm of rain in one hour, creating massive hydraulic pressure.
Sand Accumulation: Desert dust blocks small weep holes (some as tiny as 5mm), causing water to back up into the building.
A/C Condensation: The 20°C+ temperature gap between inside and outside creates moisture that must be drained to prevent interior staining.

Specification & Maintenance Checklist

For architects and contractors, ensuring longevity requires specific steps:

What Goes Wrong in Practice

We frequently see these avoidable failures in UAE projects:

Missing Sub-sills: Skipping these during installation causes water to run down the facade, staining the building.
Threshold Errors: Sliding doors, like the Cortizo COR Vision Plus, need integrated drainage tracks to prevent flooding at the base.
Silicone Blunders: Installers sometimes accidentally seal over drainage holes.

Phase

Key Action

Specification

Ensure a Class 9A watertightness rating for luxury residential.

Installation

Verify sub-sills have end caps and joints are sealed.

Maintenance

Clear weep holes every six months in dusty environments.

Get Expert Technical Support

Drainage is a proxy for the overall engineering quality of a window. At London Architectural Aluminium, we ensure every Cortizo system we fabricate is optimized for the Middle Eastern climate.

Don't leave your building envelope to chance.

→ Contact our Technical Team for a Consultation

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