How To Replace Windows On Your Home In Fairfax, VA

Replacing a window in home

Mastering Window Replacement: A DIY Guide For Fairfax Homeowners

Are your windows letting in drafts and noise, or are they just looking a bit worse for wear? Wondering how you can replace them yourself without calling in a professional?

In this guide, you’ll learn what you need to know about how to replace windows in your Fairfax, VA home.

By the end of this post, you’ll be equipped with the knowledge and confidence to tackle this home improvement project (or know if you want professional window replacement in Fairfax, VA) and enjoy the benefits of energy-efficient, beautiful new windows.

Measuring For Replacement Windows

Tools Needed For Measuring

Before starting the window replacement process, you need to gather the essential tools. These tools will help ensure accurate window measurements, leading to a smooth installation of your new windows.

Here’s what you’ll need:

  • Tape measure
  • Angle-measuring tool
  • Pencil and paper for recording measurements
  • Level
  • Utility knife
  • Square

Having these tools on hand will make the task easier and more precise, allowing you to replace windows effectively in your Fairfax, VA home, particularly in neighborhoods like Vienna.

Steps To Measure Window Openings

Accurate measurements are critical for fitting replacement windows.

Here’s an overview for accurate window measuring:

  1. Measure the Width:
    • Use the tape measure to measure the width of the window opening from jamb to jamb in three places: the top, middle, and bottom. Record the smallest measurement to ensure the replacement window fits properly.
  2. Measure the Height:
    • Measure the height from the top of the window sill to the underside of the head jamb in three places: the left side, middle, and right side. Again, use the smallest measurement.
  3. Check for Squareness:
    • Measure the diagonals from corner to corner to ensure the window frame is square. If the measurements differ by more than 1/4 inch, adjustments may be needed.
  4. Determine the Sill Angle:
    • Use an angle-measuring tool to find the slope of the sill. This helps in choosing the right replacement window with a matching sill angle.

By following these steps, you can be confident that your new windows will fit snugly into the existing window frame, minimizing gaps and ensuring a good seal.

Preparing For Window Replacement

Tools And Materials Needed

Proper preparation is key to a successful window replacement. Here’s a list of tools and materials you’ll need:

  • Screwdrivers
  • Pry bars
  • Caulk gun and elastomeric caulk
  • Putty knife
  • Fiberglass insulation
  • Hammer
  • Nails and screws
  • Safety glasses and gloves

These items will help you handle both the removal of the old window and the installation of the new one, ensuring that the process goes smoothly and safely.

Safety Precautions

Safety should always be your priority, especially if your home was built before 1978 and might contain lead paint. Here are some precautions to take:

  • Wear safety glasses and gloves to protect your eyes and hands.
  • If you suspect lead paint, contact a professional for testing and safe removal.
  • Use a utility knife to cut through paint and caulk without damaging the window frame.
  • Make sure the area is well-ventilated to avoid inhaling dust and fumes.

Following these safety measures will help you avoid potential hazards and ensure a safe working environment as you prepare to install replacement windows in Fairfax’s charming neighborhoods like Falls Church.

Discover the pros and cons of different window materials before you decide on a replacement window.

Removing The Old Window

Steps To Remove the Sash

Removing the old sash is a crucial step in the window replacement process.

Here’s how to do it:

  1. Remove Interior Stops:
    • Use a putty knife to carefully pry off the interior stops without damaging them, as you may need to reuse them.
  2. Remove the Lower Sash:
    • Slide the lower sash up and out of the window frame. If the sash cords are still attached, cut them with a sharp utility knife.
  3. Remove the Upper Sash:
    • Remove the parting stop (if present) and slide out the upper sash. Be careful not to damage the existing window frame.

Dealing With Sash Weights

Many older homes in areas like McLean, Fairfax, VA, have sash weights that need to be addressed.

Here’s how:

  1. Remove Access Panels:
    • Unscrew the access panels on each side jamb to expose the sash weights.
  2. Take Out Sash Weights:
    • Carefully remove the sash weights and sash cords. This is a good time to insulate the weight pockets for improved energy efficiency.
  3. Insulate Weight Pockets:
    • Fill the weight pockets with fiberglass insulation to prevent drafts.

Preparing The Window Frame

Cleaning And Repairing The Frame

Once you’ve removed the old window, it’s crucial to prepare the window frame for the new installation.

Here’s how you can do it:

  1. Scrape Off Loose Paint:
    • Use a putty knife to scrape off any loose or blistered paint from the window frame. This ensures a smooth surface for the new window.
  2. Patch Holes and Cracks:
    • Fill any holes or cracks in the frame with wood putty. Allow the putty to dry, then sand it smooth with a fine-grit sandpaper.
  3. Sand the Frame:
    • Sand the entire frame to remove any rough spots and ensure a smooth surface. This helps the new window fit snugly and operate smoothly.
  4. Prime and Paint:
    • Apply a coat of primer to the window frame, followed by paint. This protects the wood and provides a clean, finished look.

By thoroughly cleaning and repairing the frame, you ensure that your new window will fit properly and last longer. This preparation is especially important in older homes in neighborhoods like Oakton, Fairfax, VA.

Insulating The Frame

Proper insulation around the window frame is essential for energy efficiency.

Here’s how to do it:

  1. Choose the Right Insulation:
    • Fiberglass insulation is a good choice for most homes. It’s effective at blocking air and moisture.
  2. Bore Holes for Foam:
    • Use a drill to bore 3/8-inch holes into the window sill and head jamb. These holes will allow you to inject expanding foam insulation.
  3. Apply Expanding Foam:
    • Spray low-pressure, minimally expanding foam into the holes and around the window frame. This type of foam won’t bow the frames and will provide a tight seal.
  4. Trim Excess Foam:
    • Once the foam has hardened, use a utility knife to trim any excess so it sits flush with the frame.

Insulating the frame properly helps maintain your home’s temperature and reduces energy costs. This step is particularly beneficial in regions with variable weather.

Installing The New Window

Caulking The Opening

Caulking is an essential part of the window replacement process. It ensures that your new window is sealed against drafts and moisture.

Here’s how to do it:

  1. Apply Caulk to Exterior Stops:
    • Use a caulk gun to apply a continuous bead of elastomeric caulk to the exposed inner face of the exterior stops or blind stops on the top and sides of the frame.
  2. Caulk the Window Sill:
    • Apply two continuous beads of caulk along the window sill to ensure a tight seal when the new window is installed.

By carefully caulking the opening, you can prevent drafts and moisture from entering your home, keeping your new window tight and secure.

Positioning And Securing The Window

Correctly positioning and securing the window is vital for a smooth installation.

Follow these steps:

  1. Set the Window in Place:
    • Working from inside the room, set the bottom of the replacement window onto the sill. Tip the window up into the opening, pressing it tight against the exterior stops or blind stops.
  2. Secure with Screws:
    • Hold the window in place with one 2-inch screw driven loosely through the upper side jamb. This keeps the window in position while you make adjustments.
  3. Adjust with Shims:
    • Insert shims under the sill and behind the side jambs to center the window in the opening. Ensure the window opens, closes, and locks smoothly. Measure the diagonals to confirm squareness, then drive screws through the predrilled holes to secure the window.
  4. Trim Shims:
    • Use a utility knife to trim any excess shim material so it sits flush with the frame.

Securing the window properly is key to a stable installation and ensures the window functions correctly.

Finishing Touches

The final steps of your window replacement project add the finishing touches to make your installation look professional and complete.

Here’s how:

  1. Fill Gaps with Caulk and Foam:
    • From the outside, fill small gaps (less than 1/4 inch) with elastomeric caulk. For larger gaps, use a foam rubber backer rod before applying caulk.
  2. Reinstall or Add Stops:
    • Reinstall the interior stops you removed earlier, or add new ones if necessary. This secures the window in place and provides a finished look.
  3. Prime and Paint:
    • Prime and paint or stain the interior and exterior of the window sash and frame. This step not only improves the appearance but also adds an extra layer of protection against the elements.

By taking care of these finishing touches, you ensure that your new window looks great and performs well, enhancing the overall appearance and energy efficiency of your home in neighborhoods like Burke, Fairfax, VA.

Want to know what professional window replacement will cost in Fairfax?

Tips And Troubleshooting

Common Issues And Solutions

Issue: Frame Out-of-Squareness If your window frame is not square, the window won’t fit properly and may cause drafts or operational issues.

Solution: Use shims to adjust the window until it fits properly. Place the shims at the top and bottom corners and check for squareness by measuring the diagonals. Adjust as needed until the window is level and square.

Issue: Large Gaps Around the Window Large gaps can occur if the replacement window is slightly smaller than the existing window opening, leading to drafts and poor insulation.

Solution: Fill gaps larger than 1/4 inch with foam-rubber backer rod before applying caulk. This provides a base for the caulk and ensures a tight seal.

Issue: Drafts After Installation Even after installing your new window, you might notice drafts coming through.

Solution: Check for missed gaps or insufficient caulk. Reapply caulk where necessary, ensuring all edges are sealed. Inspect the insulation around the window frame and add more if needed.

Issue: Window Won’t Open or Close Smoothly This issue can be due to improper installation or debris in the tracks.

Solution: Check the window for alignment and make sure it is installed squarely. Clean the tracks and apply a silicone-based lubricant to the moving parts, ensuring smooth operation.

Issue: Moisture Between Glass Panes If you notice moisture or fogging between the glass panes of your double-hung windows, it could indicate a seal failure.

Solution: Unfortunately, this typically means the insulating glass unit needs to be replaced. Contact the manufacturer if your window is under warranty, or consult a professional for replacement.

Are replacement windows even a worthwhile investment?

Maintenance Tips For New Windows

  • Routine Cleaning: Clean the windows regularly with mild soap and water. Avoid abrasive cleaners that can damage the window finish.
  • Inspect for Damage: Periodically inspect the windows for any signs of damage, such as cracks in the caulk or paint. Repair these issues promptly to prevent further damage.
  • Lubricate Moving Parts: For double hung windows and other types with moving parts, apply a silicone-based lubricant to the tracks and hinges to ensure smooth operation.
  • Check Weatherstripping: Ensure weatherstripping is intact and replace any that is worn or damaged to maintain a tight seal.
  • Paint and Seal: Regularly paint and seal wooden window frames to protect against moisture and rot.

Understanding Window Replacement Options

Full-Frame Replacement Windows

Full-frame replacement windows involve replacing the entire existing window, including the frame and trim. This option is ideal for situations where the existing window frames are old, damaged, or not energy-efficient.

Full-frame replacement windows are installed by removing the entire window, including the sash, frame, trim, and sometimes even the siding. This allows for a completely new window installation, ensuring maximum energy efficiency and performance.

When To Choose Full-Frame Replacements:

  • When the existing window frames are damaged or rotted.
  • When you want to change the window style or size.
  • For improved insulation and energy efficiency.

Pros And Cons:


  • It provides the opportunity to address any underlying issues, such as water damage or rot.
  • Allows for the installation of larger windows or a different style.
  • Enhances energy efficiency by installing a completely new window system.


  • It is more expensive and time-consuming than inserting replacement windows.
  • Requires more labor and can be disruptive to your home.

Insert Or Pocket Replacement Windows

Insert replacement windows, also known as pocket windows, fit inside the existing window frame. This option is suitable for homes where the existing frames are in good condition, and you want a quicker, less invasive installation.

Insert replacement windows are designed to fit inside the existing window frame without removing the trim or siding. These windows are custom-sized to fit the existing opening and are installed by removing the old window sash and placing the new window into the pocket.

Conditions For Using Insert Replacements:

  • When the existing window frames are still in good condition.
  • When you want to maintain the current window trim and siding.
  • For a quicker and less invasive installation process.

Pros And Cons:


  • Less expensive and faster to install compared to full-frame replacements.
  • Minimal disruption to the interior and exterior of your home.
  • Preserve the existing window trim and siding.


  • Slightly reduces the glass area of the window due to the insertion into the existing frame.
  • Not suitable for frames that are damaged or not energy-efficient.

Choosing the right type of replacement window depends on the condition of your existing window frames and your goals for energy efficiency and aesthetics. In Fairfax, VA, particularly in neighborhoods like Chantilly, considering these factors will help you make an informed decision and achieve the best results for your home.

Should you do a window replacement or window repair project?

Replace Your Windows With Clifton Exteriors

When it comes to replacing windows in Fairfax, VA, Clifton Exteriors offers top-notch expertise and high-quality replacement windows. Our team ensures a seamless and stress-free window replacement process tailored to meet your specific needs.

Don’t wait to upgrade your home’s efficiency and aesthetics—fill out our contact form today or give us a call. Let Clifton Exteriors open the window to a brighter, more energy-efficient future for your home!