How To Fill Gap Between An Aluminium Window & Wall [Step By Step Guide]

Aluminum windows are among the most popular types in commercial and industrial spaces because of their several benefits. However, sometimes we might have to deal with the gaps between the aluminum window and the wall.

In case you're wondering how you can fill the gaps between your aluminum window and the wall, we've researched this topic to help you out.

To fill the gap between your aluminum window and the wall:

  1. Prepare the materials needed.
  2. Clean the gap between your aluminum window and the wall.
  3. Fill the gap until all areas are covered.
  4. Smooth and clean the surface of the sealant using mineral spirits.
  5. Let the silicone sealant dry.
  6. Coat the sealant with paint if necessary.

It may seem overwhelming, but we will dive into further details to help you fill those stubborn gaps between your window and the wall, so keep reading this post to learn more. With that said, let's get right into it!

Sample of modern window profile on sill., How To Fill Gap Between An Aluminium Window & Wall [Step By Step Guide]

How To Fill Gap Between An Aluminium Window & Wall [Step By Step Guide]

Modern design vertical roof window with white light metal covering

There's no surprise that aluminum is one of the most common materials used on windows.

Aside from being affordable, aluminum windows are best known for their durability, thermal efficiency, and adaptability to different designs.

Sometimes, you might notice a visible gap between the window frame and the wall. That is because when aluminum is exposed to high temperatures, the material expands, thus, causing the crack.

It is a natural phenomenon; the best thing to do is to put a filler between the frame and the wall to fix the gap. Here is how to do it.

Technician man hand holding and using manual caulking glue gun or silicone tube to seal the expansion joint between cement wall and steel material at aluminium door.

1. Prepare The Materials Needed

Silicone sealants are used in the construction industry more than a lot due to their numerous benefits. It is a flexible material that can adapt to heat and cold while acting as an adhesive that wraps up fixes.

Silicone sealants stick to aluminum; that's why it is the best choice to fill the gap between the aluminum window and the wall.

Before we begin our project, ensure that you have your silicone sealant and the other tools we will need.

  • Sealant gun
  • Mineral spirits
  • Safety gloves
  • Safety mask
  • Clean damp cloth
  • Cleaning brush
  • Sealant removing tool (optional)

See this silicone sealant on Amazon.

2. Clean The Gap Between The Aluminium Window And The Wall

One of the most important steps, yet often forgotten, is to prepare the area where the sealant will be applied.

Dust particles or dirt can cause the sealant not to adhere as much as expected. That's why it is recommended to clean the area first before proceeding with the application.

Using a damp cloth, wipe the area until all dirt and dust are removed. Old paints should also be removed, or it might affect the adherence to the new sealant.

If the gap you're trying to fix has been sealed before, use a sealant-removing tool and a cleaning brush to remove the old sealant. Ensure you get rid of all the grime so the new sealant will stick properly.

3. Fill The Gap Until All Areas Are Covered

The gap near the window is filled with foam

Load the sealant into the canister and cut a 45-degree angle onto the opening.

Next, angle the gun at 45 degrees before starting with the application.

Press the trigger and make your way around the frame until all gaps are covered. Sometimes you will need to put more pressure on the trigger so the sealant will come out.

4. Smooth And Clean The Surface Of The Sealant Using Mineral Spirits

After applying the sealant, damp clean cloth with mineral spirits. Gently trace the surface of the sealant until all areas are smoothened. You can also use the same cloth to get rid of excess sealants.

5. Let The Silicone Sealant Dry

Hands of worker using a silicone tube for repairing of window indoor

Once you're done cleaning and smoothing the sealant, allow the silicone to dry.

It might take up to 30 minutes or longer, so make sure that the sealant will not get in contact with any liquid until it's completely dry to avoid wasting the sealant and going through the process again.

6. Coat The Sealant With Paint If Necessary

If you want to hide the sealant so it will not ruin the overall view of your window, you can paint over it once it cures. However, silicone can be a bit tricky and may require more effort, so the paint will stick over it.

To paint a silicone sealant, you first need to wipe the surface with a damp cloth soaked in denatured alcohol. It will roughen the surface to help the paint adhere.

Next, apply a layer of acrylic latex on top of the silicone sealant. This will act as a second layer of your gap filler which will hold the paint. Paints will not directly stick onto silicone, but they will on acrylic latex.

Once the layer of acrylic latex is dry, you may now coat it with any oil-based paint.

Check out this acrylic latex on Amazon.

Aluminum VS Vinyl - Which To Choose For Your Window?

There are several factors to consider when choosing between aluminum and vinyl. While both have their fair share of benefits and disadvantages, aluminum and vinyl are two of the most popular window materials.

An aluminum window is a type of window frame with a glass pane similar to wood. It is made from aluminum, a durable material often used in construction.

On the other hand, a vinyl window is made from a plastic material called PVC. It mimics the appearance of wood but comes in a lighter weight than wood.

Which is better will depend on your preference. However, here are some things you might want to take a closer look at before deciding.


Aluminum and vinyl are both known for their durability. The downside of using aluminum is it is prone to corrosion, unlike vinyl.

Also, aluminum dents and chips can be visible when the frame gets damaged, while chipping and dents can be nearly invisible on vinyl.

However, aluminum is known for being stronger than vinyl. It can withstand more extreme weather conditions than vinyl, especially in severe heat and cold areas.


Another thing to consider when choosing the suitable material for your window frames is the material's life expectancy.

While vinyl windows last 20-40 years, depending on the climate and how well it is taken care of, aluminum windows are expected to last up to 45 years.

However, due to several factors such as corrosion, sometimes aluminum windows can only withstand the test of time for up to 15-20 years.

Cost And Maintenance

Although both materials are considered cheaper than traditional wooden frames, vinyl is 33-58% less expensive than aluminum.

When it comes to maintenance, vinyl is less likely to require regular maintenance, while aluminum needs to be cleaned with aluminum cleaner regularly.

In addition, aluminum windows require frequent lubrication on some of their crucial parts to prevent them from getting stuck due to rust and corrosion.

Warping And Insulation

While vinyl windows expand drastically on extreme heat, aluminum windows are less likely to warp despite being exposed to outside elements. It will, but the expansion is nearly unnoticed when it happens.

Regarding insulation, vinyl can be a better insulator than aluminum due to vinyl's R-value.

Water Resistance

Vinyl is best known for being water-resistant, making it an ideal material to use in several areas of your home that often experience high humidity and moisture.

On the other hand, although aluminum is water-resistant, it can still rust over time, and some of its parts may develop rust since aluminum is more prone to condensation.


Regarding the overall look, vinyl offers a more aesthetically pleasing appearance due to its variety of designs available in the market.

Vinyl windows can also be painted when coated with primer, while aluminum windows can be a bit more challenging to paint.

Our Final Thoughts

Close-up Of Person Hand Applying Silicone Sealant With Silicone Gun On Window

The gap between your aluminum window and the wall can be irritating. Good thing you can apply a layer of silicone sealant to fill the void.

Not only will sealing the gap offer a better look for your window, but it can also prevent further structural damage in the long run.

Before you go, don't forget to check out these posts, too:

How To Repair Rotted Window Frame [Inc. Interior And Exterior]

Vinylmax Windows Vs. Pella Vs. Andersen: Which To Choose?

One comment

  1. The gap between your aluminum window and the wall can be irritating. Good thing you can apply a layer of silicone sealant to fill the void. Not only will sealing the gap offer a better look for your window, but it can also prevent further structural damage in the long run.

Leave a Reply

Your email address will not be published. Required fields are marked *