Why does water come through the window when it rains? Causes and Solutions

It is a more common situation than it seems: a Levante storm arrives on the Costa Blanca, and water begins to seep through the windows. Damp spots on the walls, puddles on the windowsill, mold in the corners of the frame. It is not a simple coincidence: it is a sign that something is wrong with your enclosures.

Main causes of leaks

1. Old or low-quality windows

Aluminum windows without thermal break or deteriorated wooden frames lose weathertightness over time. The joints dry out, the closures stop adjusting correctly and the water finds its way inside.

If your windows are more than 15-20 years old, their water tightness capacity is likely to be severely compromised.

2. Defective installation or deteriorated sealing

A poorly installed window is a window doomed to have leaks, no matter how good it is. The sealing between the frame and the work must be perfectly executed, with polyurethane foams and elastic sealants that absorb the movements of the structure.

3. Obstructed drainage channels

All quality windows have drainage holes at the bottom of the frame to evacuate water that may enter the chamber. If these channels become clogged with dust, sand or debris, the water accumulates and eventually seeps inside.

4. The shutter box

In many coastal homes, the leak does not come from the window but from the shutter box. Old, uninsulated drawers are a weak point through which water, air and noise enter. Systems like the RolaPlus o VariNova from Kömmerling eliminate this problem with hermetic sealing and reinforced insulation.

Forget home remedies

Applying silicone on the outside, sticking adhesive tape or placing cloths on the windowsill are temporary patches that do not solve the underlying problem. At best, they hide the leak; at worst, they worsen it by preventing proper water drainage.

The definitive solution

If leaks are recurrent, the solution involves replacing the windows with high tightness systems. Kömmerling PVC profiles are tested at water pressures far exceeding those generated by a Mediterranean storm:

Signs that you need to replace your windows

• Damp stains or mold around the frame
• Drafts with the windows closed
• Outside noise is clearly audible
• Frequent condensation between the panes
• Visible leaks through the rail or joints

At ventana.plus we are official Kömmerling installers in the Marina Alta. If you have leaks in your windows, we can make an assessment without obligation and propose the most appropriate solution for your home.

Quick Diagnosis: Table of Causes and Solutions

Preventive Advice

Most leaks are prevented with basic maintenance: check the rubber seals every 2 years, clean the frame drains 2 times a year (spring and autumn) and renew the perimeter silicone sealant every 10-15 years. These simple actions can prevent moisture damage that costs between €500 and €5,000 in repairs to walls, floors and furniture.