Aluminium Window Installation Process Step by Step: A Complete Guide

December 16, 2025

Installing aluminium windows may look simple, but most performance issues, such as leakage, air gaps, rattling, or misalignment, happen because the installation was not done correctly. Even the best aluminium window design cannot perform well if the frame isn’t fitted with precision.

Many homeowners realise this only after a few months.

A window that shakes during the wind, lets in rain during the monsoon, or becomes difficult to open and close is almost always a result of improper installation.

These issues affect comfort, increase maintenance costs, and reduce the long-term durability of the window.

That’s why understanding the installation process matters. When you know how each step works, from preparing the opening to sealing the final frame, you can ensure the installer follows the right method and delivers a clean, accurate finish.

This guide breaks down the aluminium window installation process step by step, helping you get a smooth, long-lasting result for your home.

Let’s begin with the basics.

Tools and Materials Required

Before the installation starts, gather everything necessary. Aluminium window systems require precision tools because the frames are lightweight yet highly engineered. Having all materials ready ensures the installation progresses without disruption.

Here’s a simple breakdown of what you will need:

Tools

• Spirit level
• Measuring tape
• Screwdrivers and a drill
• Set square
• Caulking gun
• Safety gloves and eyewear
• Fiberglass safety guards
• Hammer
• Sandpaper
  Packers and spacers

Materials

• Aluminium window frame and sashes
• Screws and anchors
• Exterior-grade silicone sealant
• Weatherproofing tape or flashing
• Sub-sill assembly (if required)
• Cleaning cloth and scraper

A quick reference table:

Tool/Material	Purpose
Spirit Level	Ensures the window is perfectly horizontal and vertical
Packers	Helps adjust levels and fill structural gaps
Sealant	Prevent water and air infiltration
Set Square	Ensure the frame sits flush with the wall

These basics form the foundation for a hassle-free installation. Once everything is ready, it’s time to prepare the site.

Pre-Installation Preparation

Even the best aluminium window design won’t perform well if the opening isn’t properly prepared. This stage is crucial because the frame needs to sit in a clean, level, and structurally sound space.

1. Measure the Opening

Begin by measuring the width, height, and diagonal lengths of the opening. If the diagonals vary significantly, the space isn’t square, which can cause issues such as difficulty closing the window later. Accurate measurements also help identify whether the window fits with adequate tolerance for packers and sealant.

2. Inspect for Structural Defects

Scrutinize the area for cracks, moisture damage, uneven plaster, or gaps. These issues should be fixed before installation. Any structural weakness can affect the frame alignment and long-term stability of aluminium windows for home use.

3. Clean the Area

Dust, debris, or loose plaster can keep the frame from settling properly. Clean the opening thoroughly to ensure a smooth installation base.

4. Pre-Drill Holes

Drill holes in the reveals like top, middle, and bottom. This step, recommended by professional installers, speeds up the fixing process and ensures consistent anchoring.

Once the opening is measured, cleaned, and prepared, the actual installation can begin.

Step-by-Step Aluminium Window Installation Process

This section breaks down the core process. Whether you are watching your installer work or managing a small-scale DIY project, these steps will help you understand what proper aluminium window installation looks like.

Step 1: Re-Check Window Measurements

Double-checking measurements may seem repetitive, but precision is everything in aluminium window systems. Before placing the frame into the opening, confirm its size against the opening one more time.

A slight error here can cause:

• Poor sealing
• Uneven gaps
• Difficulty locking or sliding
• Long-term rattling or noise intrusion

If the window is too tight or too loose, address the issue before proceeding.

Step 2: Position the Frame in the Opening

Lift the aluminium window frame carefully with at least two people, one on the inside and one outside. Aluminium frames are light but can get damaged if handled improperly.

Once positioned:

• Place packers beneath the frame to support it.
• Adjust packers to level the bottom edge.
• Check horizontal alignment using a spirit level.

This step ensures the window won’t tilt or jam later.

Step 3: Align and Make the Frame Flush

Now, align the frame so it sits flush with the wall.

Use a set square to check whether the vertical edges align cleanly with the interior wall surface. Flush positioning is essential because it helps:

• Prevent water seepage
• Maintain correct drainage
• Support smooth sash movement
• Create a premium finish for your aluminium window design
• Make adjustments by gently pushing the frame from either side until it fits perfectly.

Step 4: Fix the First Side of the Frame

With the frame level and flush, secure the first side.

Here’s how:

• Use the pre-drilled reveal holes.
• Insert three screws such as top, middle, and bottom.
• Tighten carefully without bending the aluminium profile.

Securing one side stabilizes the frame, allowing the rest of the installation to happen without additional support.

Step 5: Fix the Second Side of the Frame

Before anchoring the second side:

• Inspect for gaps between the wall and frame.
• Insert packers into gaps to ensure even pressure across the frame.
• Tap the packers gently with a hammer until the frame becomes firm and aligned. Then, tighten screws in the same top–middle–bottom pattern.

This step must be done slowly and patiently, an uneven frame can compromise the operation of aluminium windows for home use.

Step 6: Install the Sashes or Sliding Panels

Once the frame is secured, it’s time to fit the sashes or sliding panels.

Follow these checks:

• Insert the sash carefully into the hinges or rollers.
• Confirm the sash moves smoothly, no scraping or stiffness.
• Check locking alignment.
• Test open-close movement multiple times.

If the window includes sliding panels, adjust the rollers to ensure effortless gliding along the tracks.

Step 7: Seal and Weatherproof the Window

Sealing is one of the most important steps, especially in Indian climates where heavy rain and dust storms are common.

What to do:

• Apply weatherproof tape around the frame perimeter.
• Seal gaps with high-grade exterior silicone sealant.
• Smooth the sealant line to avoid pockets where water can collect.

Proper sealing enhances thermal insulation and protects your aluminium window system from long-term damage.

Step 8: Add Finishing Touches

The final touches give the installation a polished, professional look.

This includes:

• Adding interior and exterior trims or beading
• Cleaning excess sealant
• Snapping off visible packer ends
• Wiping the frame and glazing
• Removing the protective film from the aluminium

A clean finish also makes the window look seamless with your wall surface.

Tips for Post-Installation Checks

Once installation is complete, a thorough inspection helps ensure everything is in order.

Here’s what to check:

• The sash operates smoothly without resistance.
• Locks and handles align properly.
• No visible gaps around the frame.
• Sealant is evenly applied with no cracks.
• The frame isn’t pulling towards one side due to overtightened screws.
• Water spray test, which is an option, but ensures sealing is sound.

These checks guarantee long-term performance and prevent issues like rattling or leakage.

Why Professional Installation Matters?

While it’s possible to understand the process, installing aluminium windows demands skill. Modern aluminium window systems are engineered with precise tolerances. Incorrect handling can bend a frame, disrupt sash alignment, or leave gaps that affect insulation.

Professional installers ensure:

• Accurate leveling
• Seamless sealing
• Proper hardware fitting
• Compliance with safety norms
• Performance according to manufacturer standards

DIY installation might work for small, simple windows, but larger units like sliding, tilt-turn, or combination systems require expert handling.

Why Choose Alteza Aluminium Windows?

Alteza is known for delivering premium aluminium windows for home projects across India. Every window system is engineered to handle Indian climate variations like extreme sun, humidity, and monsoon conditions with consistent performance.

Here’s what makes Alteza stand out:

• Precision-crafted aluminium window designs
• Smooth, long-lasting hardware and movement
• Excellent thermal and acoustic performance
• Wide range of configurations and finishes
• Professional installation support
• Long-term durability with minimal maintenance

Our windows not only elevate aesthetics but also create a comfortable living environment with superior insulation and reliability.

Wrapping Up

Installing aluminium windows the right way isn’t just about placing a frame into the wall. It’s a carefully structured process that ensures stability, weather protection, and flawless daily use. From accurate measurements to proper sealing, every step contributes to how well your aluminium window performs for years to come.

If you want a perfect fit and a dependable installation that enhances the beauty and performance of your home, choosing a trusted brand makes all the difference.
Alteza delivers premium aluminium window systems designed for long-lasting performance, effortless operation, and a seamless finish for every modern Indian home.