How to Install Sealing Lips for Aluminum Window Sills: A Step-by-Step Guide

Renovating your home or undertaking a construction project? One crucial aspect is ensuring that your window sills are properly sealed to prevent water ingress and enhance insulation. At, we offer high-quality sealing lips that are perfect for this job. In this guide, we’ll walk you through the steps to install sealing lips on your aluminum window sills.

Why Use Sealing Lips?

Sealing lips play a vital role in waterproofing and securing the installation of your aluminum window sills. They are placed on the screw side of the window sill, between the screw side and the window profile. Here’s why they are essential:

  • Waterproofing: Prevents water from penetrating into the structure, protecting your home from moisture damage.
  • Insulation: Improves thermal insulation around the window area, contributing to energy efficiency.
  • Durability: Made from robust materials that can withstand various weather conditions.

Materials Needed

  • Sealing lips (available in black, white, and grey)
  • Screwdriver or drill
  • Measuring tape
  • Utility knife
  • Screws
  • Aluminum window sill
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Step-by-Step Installation Guide

Step 1: Measurement and Preparation

  1. Measure the Window Sill:
  • Use a measuring tape to determine the exact length of the window sill.
  • Ensure accuracy to cut the sealing lips to the correct size.
  1. Cut the Sealing Lips:
  • Using a utility knife, cut the sealing lips to match the length of the window sill.
  • Make precise cuts to ensure a snug fit when installed.

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Step 2: Positioning the Sealing Lips

  • Place the Sealing Lips:
  • Position the sealing lips on the screw side of the window sill.
  • Ensure they are between the screw side and the window profile for optimal sealing.
  • Align Properly:
  • Align the sealing lips carefully to ensure they cover the entire length of the window sill.
  • Check for any gaps or misalignments.

Step 3: Installing the Window Sill

  1. Secure the Window Sill:
  • Place the aluminum window sill in its designated position on the window frame.
  • Ensure that the overhang (at least 30 mm beyond the fa├žade) is correctly positioned.
  1. Screw the Window Sill:
  • Using a screwdriver or drill, screw the window sill into the window frame.
  • Ensure that the sealing lips remain in place during this process.
  • Use the provided screws, and cover them with matching screw caps if necessary.

Step 4: Final Checks

  1. Inspect the Installation:
  • Check the entire installation for any gaps or misalignment.
  • Ensure the sealing lips are secure and provide a tight seal.
  1. Waterproof Testing:
  • Simulate a rain test by spraying water on the window sill to check for leaks.
  • Ensure no water penetrates into the structure, confirming the sealing is effective.

Benefits of Using Sealing Lips from

  • Customizable Options: Available in black, white, and grey to match your design needs.
  • High Quality: Made from durable materials that ensure long-lasting performance.
  • Easy to Install: Designed for straightforward installation, providing a reliable seal.


Installing sealing lips on your aluminum window sills is essential for ensuring a waterproof and well-insulated home. By following this guide, you can achieve a professional and secure installation. At, we offer top-quality sealing lips starting from just €2.72, available in various colors to suit your needs.

Ready to enhance your renovation project? Visit our website or contact us today for more information and to place your order.

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