Your windows allow light to fall upon walls painted in your favorite colors. They add an extra dimension to your decor while keeping the weather out and adding security.

When supported with exterior window casing, a few strategically placed windows provide not just beauty but also can add value to your home through added natural lighting and an enhanced aesthetic appeal.

>When it comes to transforming your home, exterior window casing is an excellent way to do so. That is, perhaps, one of the main reasons why so many people opt for this. However, upkeep is an important part of the deal with such an exquisite element.
Therefore, understanding how to repair or replace exterior window casing will come in handy, no matter the occasion.


How to repair/replace exterior window casing?


1. Take Off the Old Casing

Take Off The Old Casing How To Repair Exterior Window Casing

With the help of a wooden block placed against the window, take the old casing off using a pry bar. Next, slide the pry bar into the space between the casing and the building and bring the entire old casing off its axis.

Tools Required: This step requires using a pry bar and a wooden block.


2. Waterproof the Window

Waterproof The Window How To Repair Exterior Window Casing

Use an adhesive-backed window flashing to make the casing and window resistant to water. With the help of a scissor, cut the flashing to the desired length and scale the top and bottom edges. Once done, place the piece between the base of the building and the siding of the window.

Tools Required: This step requires the use of an adhesive-backed window flashing. 


3. Get the Measurements in Place

Get The Measurements In Place Exterior Window Casing

Use a measuring tape to determine the length of casing required. You can refer to the old casing for a sense of what the measurement would be. However, we recommend drawing new measurements to get a more real-time understanding. Note these down in pencil and save them for later.

Tools Required: This step requires a measuring tape and a pencil.


4. Cut the Casing to the Right Measure

Cut The Casing To The Right Measure Exterior Window Casing

We would strongly recommend you put on a study facemask, polycarbonate safety glasses, and earplugs when heading into this step.

You will use a carbide-tipped saw blade to cut the casing you have previously measured. Then, using a circular saw, you can even out the exterior window casing and draw the piece into a neat, straight cut that sits well against the building.

It is best to keep the casing slightly longer than required as it would offer more room to improvise later on in the process.

Tools Required: This step requires a facemask, safety glasses, earplugs, and a circular saw.


5. Prepare & Pre-Drill

Prepare Pre Drill How To Repair Exterior Window Casing

The key step to any successful installation? Preparation. This step accounts for just that.

Here, you will pre-drill nail holes through the external section of the casing. Then, at the top and the bottom, you’ll need to drill a single hole with space for approximately two more holes within that area.

It is good to ensure that these are all equidistant from one another. It not only looks neater but also holds better in the long run. You should also keep in mind how you would be installing the casing to ensure the placement is maintained.

Tools Required: This step requires the use of a drill as well as a measuring tape.


6. Add the Nails to the Casing

Add The Nails To The Casing How To Repair Exterior Window Casing

Now that you have your basic measurements and exterior window casing items picked out, it’s time to start nailing. This part can be tricky, as most walls aren’t exactly straight and level. Take your time and make sure everything is aligned perfectly before nailing the exterior window casing into place.

It’s important to make sure the baseboard is perfectly smooth and level before attaching it. This way, the bottoms of the pieces you put up against it will be straight and true, which will give your Exterior Window a clean, finished look. 

Tools Required: This step requires the use of finishing nails.


7. Cover the Casing with Caulk

Cover The Casing With Caulk Exterior Window Casing

When you reach this step, you may find that some areas are uneven due to inconsistencies in the wall’s surface or other factors. Simple fix: caulk.

Use a caulk gun to apply a bead of latex caulk around the outside of the window frame where the window and building’s siding meet. Start at the top and work your way down, making sure that you apply an even layer all the way around.

Try not to cause any drips or runny spots. Instead, use your finger or a moistened cloth to smooth out any bumps or ridges from the excess caulk.

Tools Required: This step requires latex caulk and a caulk gun.


8. Fill the Nail Holes

Fill The Nail Holes How To Repair Exterior Window Casing

After you’ve fully inserted the nails into the Casing, you may want to fill in the holes that remain as an effect. You can fill these with painter’s putty or one of the new high-tech alternatives.

Push putty or caulk into each hole and scrape off any excess. You may have to use a little bit of sandpaper to smooth it down and get rid of any drips after the filler dries. The time it takes to dry depends on the filler you’re using.

A good tip here is to choose the color and texture of your filler compared to the colors and textures of your surrounding surfaces, to get a complete look to the overall finish.

Tools Required: This step requires using painter’s putty or its relative alternative.


9. Beautify the Casing

Beautify The Casing Exterior Window Casing

And finally – perhaps the most enjoyable function – painting and beautifying the newly replaced Casing. This step allows you to explore the possibilities and even change the window’s appearance with a new color and a fresh layer of paint.

Following the instructions on your paint can, prime and paint the Casing as needed. You may want to let the primer sit for a few hours or even overnight before applying a layer of paint. 

Seal it with a water-repellent sealant as soon as possible after painting so the sealant can do its job by preventing water damage.

An important part of this process is to cover any surrounding bushes and grass with plastic sheeting and tarps to avoid damage.

Tools Required: This step requires paint, primer, sealant, plastic sheeting, and tarps.


Need a recap? Here’s a quick video you can watch:


Exterior window casing can be a highly effective and aesthetically pleasing addition to a home. In addition, the window casing gives you the ability to dress up your home and have privacy from the exterior vantage point.

If you enjoy the appeal of an exterior window casing, you may benefit from understanding how to install, repair, and even replace it. While several professionals can do this for you, understanding this process will only be your advantage.


Disclaimer: The views expressed in this article are based on our team’s knowledge and experience. The results from instructions provided in the blog may vary from case to case basis. We strictly advise our readers to verify all the information provided here through their sources. Echon, its employees, partners, distributors, or directors are not responsible for any consequences, good or bad, that may arise from following the instructions on this blog for an individual or a company from the USA or abroad. The information is being provided to help our readers and our community and is by no means official. We are not legally or morally liable for any damage, financial or non-financial, that may be caused by following the suggestions or information provided in our blogs.