How to Flash a New Construction Window?

Introduction

Flashing a new construction window is a critical step in ensuring the long-term durability and weather resistance of a building. Proper flashing prevents water infiltration, which can lead to structural damage, mold growth, and reduced energy efficiency. This article outlines the essential steps for effectively flashing a new construction window, ensuring a watertight installation.

Preparing the Window Opening

Cleaning and Inspection

Before installing the flashing, it’s crucial to clean the window opening thoroughly, removing any debris, dust, or old building materials. Inspect the opening for any irregularities or damage that might affect the flashing process.

Applying a Sill Pan

A sill pan, either prefabricated or site-built, should be installed at the bottom of the window opening. This pan directs any water that might enter the opening outward, preventing it from reaching the interior of the wall.

Installing Flashing Materials

Sill Flashing

Start by applying a self-adhesive flashing tape to the sill, extending it up the sides of the opening by several inches. Ensure that the tape is smooth and free of wrinkles or air bubbles.

Jamb Flashing

Next, apply flashing tape to the vertical sides of the window opening, overlapping the sill flashing. This tape should extend beyond the top of the opening to ensure complete coverage.

Head Flashing

After the window is installed, apply flashing tape across the top of the window, overlapping the jamb flashing. This head flashing is critical for directing water away from the top of the window and preventing it from entering the wall.

Sealing and Finishing

Sealant Application

Apply a high-quality sealant around the perimeter of the window, focusing on the edges where the flashing tape meets the window frame. This provides an additional barrier against water infiltration.

Insulation and Trim Installation

Once the flashing is in place and sealed, you can proceed with installing insulation around the window and finishing the exterior with trim or cladding, ensuring that the flashing is not punctured or compromised during this process.

Conclusion

Properly flashing a new construction window is essential for maintaining the integrity and efficiency of a building’s envelope. By following these steps and using quality materials, you can ensure a watertight installation that protects against water damage and enhances the overall performance of the window. Remember, attention to detail during the flashing process is key to the long-term success of the installation.