Aluminum Windows and Water Leakage: Rainy Season Protection

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Aluminum windows themselves rarely leak; most water leakage happens at the seals, drainage channels, sill joints and installation gaps around the frame. Proper gaskets, correctly sloped sills, open drainage holes and a sealed perimeter stop rainwater before it reaches the wall.

Why windows leak during the rainy season

Rain rarely pushes straight through a closed window. It usually enters where wind drives water against the frame and finds a weak point: a worn gasket, a clogged drainage slot, or a gap between the frame and the wall. Wind pressure during winter storms makes these small paths much more serious than they look on a calm day.

Common signs include damp patches on the wall below the window, water on the floor near the sill, bubbling paint, or a musty smell in the room after a storm. Finding where the water first appears inside helps trace the source.

How aluminum window design keeps water out

A well-made aluminum window uses several layers of protection. The outer frame and sash meet with compression gaskets, and the design includes a drainage chamber that collects any water that gets past the outer seal and guides it back outside through small weep holes.

Continuous gaskets on the sash and frame
A pressure-equalized or drained profile
Sloped sill with open drainage outlets

When these features are designed and assembled correctly, water that reaches the profile has a clear path out instead of collecting inside.

Checking your existing windows for leaks

Start with a simple test on a dry day. Have someone spray the outer edges of the window with a garden hose while you watch the inside, working from the bottom upward. This slow method shows exactly where water enters.

Also inspect the drainage holes in the sill. If they are blocked with dirt, insects or paint, water cannot escape. Look at the gaskets for cracks, flattening or missing sections, and check the silicone or sealant around the outside frame for gaps.

Sealing and repairs that actually work

Many leaks can be fixed without replacing the window. Clean and clear the drainage holes, replace worn gaskets with the correct profile, and reseal the outer joint between frame and wall with a suitable exterior sealant. Surfaces must be clean and dry for the sealant to bond.

If water enters at the top corners or the sill joints, the problem is often in the installation rather than the window. Resealing those points carefully usually solves it.

Installation details that prevent future leaks

Most water problems trace back to installation. The window should be level and plumb, with the sill sloped slightly outward so rain runs off instead of sitting on the surface. The gap between the frame and the wall must be filled with appropriate insulation and then sealed on both the outside and inside.

On new projects, flashing or a waterproof membrane should be coordinated with the structural contractor so water cannot run behind the frame. Ask your installer to show you how the sill and drainage are finished before they leave.

When to call a specialist and what to expect

Call a professional if water persists after cleaning and resealing, if the frame itself is warped, or if you see water entering from several sides at once. A proper inspection includes the window, the wall opening and the installation details.

At our Tel Aviv workshop we start with photos and an on-site measurement, then provide a written specification and approval before any work begins. Repairs and replacements are made to measure and fitted so the seal is correct from the start.

Frequently asked questions

Do aluminum windows leak more than other types?

Not inherently. Leaks usually come from worn gaskets, blocked drainage or poor installation rather than the aluminum itself. A correctly designed and fitted aluminum window sheds water effectively.

How can I stop water coming in at the bottom of my window?

Clean the drainage holes in the sill first, then check the gaskets and the sealant under the sill joint. If the sill is not sloped outward, the installation may need adjusting.

Can I fix a window leak myself?

Simple fixes such as clearing drainage holes and replacing a gasket are often manageable. Structural or installation problems should be inspected by a specialist to avoid hidden damage.

How do I know if the leak is from the window or the wall?

Do the slow hose test from the bottom upward. If water appears inside only when you spray a specific joint, the problem is at that joint, whether in the window or its connection to the wall.

Common mistakes to avoid

Many owners apply silicone over a leaking joint without clearing the drainage path, which traps water inside. Blocked weep holes and gaskets replaced with the wrong profile cause repeated leaks.

Our recommendation

Inspect and clear drainage holes and gaskets at the start of the rainy season, and reseal the outer frame joint with a proper exterior sealant. If water still enters, get an on-site measurement and inspection before deciding on repair or replacement.

Summary

Aluminum window water leakage is usually fixable through clean drainage, sound gaskets, proper sealing and correct installation. A short inspection before winter prevents most rain damage.

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