The Perfect Bedroom Window Replacement: A Step-By-Step Guide

Replacing a bedroom window is a moderately challenging task that requires some carpentry skills and home remodelling experience. It involves removing the old window, preparing the window frame, installing the new window, and sealing it for efficiency. The process can be simplified if the window is on the ground floor and easily accessible from the outside. The cost of window replacement typically ranges from $230 to $1,230 per window, with an average cost of around $730 per window.

The first step is to measure the dimensions of the old window frame to ensure that the replacement window is the correct size. This includes measuring the width and height at multiple points, as well as checking the squareness of the frame by measuring the diagonals. Once the measurements are taken, the old window can be removed by taking out the sash and any weights, pulleys, or screws. The window frame should then be cleaned and prepared by scraping off old paint and patching any holes.

The next step is to place the new window into the frame to test its fit. A bead of caulk should be applied to the exterior stops, and then the new window can be set into the opening. The window should be centred and secured with mounting screws. The sash should be opened and closed to test its function, and shims may be added to adjust the levelness of the window. Finally, the inside stops and any other trim can be replaced, and the exterior gaps between the window and casing should be caulked.

Measure the window frame

Measuring the window frame is a crucial step in replacing your bedroom window. Here is a detailed, step-by-step guide to help you get it right:

Step 1: Use the Right Measurement System

Use the metric system and measure in millimetres, not inches. This provides a finer level of accuracy and ensures no room for error when the window manufacturer converts your measurements.

Step 2: Measure the Width

Measure the width of the window frame in at least three places: the top, middle, and bottom. This is important because the opening may not be perfectly square. Record the smallest of these three measurements, as this will be the width you use when calculating the size of your new window.

Step 3: Measure the Height

Similarly, measure the height of the frame in three places: the left side, middle, and right side. Take the shortest of these three measurements as the height you will use for ordering your new window.

Step 4: Measure the Depth

Find the depth of the window opening by running a tape measure from the outside of the frame to the inside. Do this in several locations and use the smallest measurement as your final dimension. If your window doesn't open, add the depth measurements of both sides of the glass and the thickness of the window pane (usually 1/8" or 3mm).

Step 5: Repeat for Each Window

If you have multiple windows to replace, repeat this process for each one. It is important to measure each window individually, as their dimensions may vary slightly.

Step 6: Take Notes and Double-Check

Make sure to write down all your measurements and double-check them for accuracy. This is crucial because any errors will result in ill-fitting windows, and window manufacturers will not accept responsibility for incorrect measurements. If you are unsure, consult a professional installer or builder for peace of mind.

By carefully measuring your bedroom window frame, you can ensure that your replacement window will fit perfectly, maintaining the comfort, energy efficiency, and aesthetic appeal of your home.

Choose window type

When choosing a window type, there are several factors to consider. Firstly, think about the functionality you require. Do you need a window that opens, and if so, how? For example, casement windows are attached to their frame by side hinges and are simple to operate, making them a great energy-efficient option. In contrast, fixed windows do not open and are instead used to maximise natural light. Alternatively, if you're looking for a window to fit a small space, a hopper window that opens from the top may be a good option.

Next, consider the style of your home. If you're renovating a period home, it's important to choose a window style that is authentic to the era. Small casement windows are associated with cottages, while multi-pane, vertically-oriented sliding sash windows are typical of the Georgian and early Victorian eras. If your home is contemporary, you may want to opt for larger windows with minimal framing. Bay windows, for instance, can add architectural interest and make a room feel bigger and brighter.

Additionally, think about the material of the window frame. uPVC is a popular choice as it's usually the cheapest option, low maintenance, and won't shrink or warp. Timber windows are ideal for period-style homes as they offer a traditional feel and are available in hardwoods and softwoods. Aluminium is another great option as it's strong, comes in slim frame widths, and can accommodate triple glazing.

Finally, don't forget to consider your budget. Window costs can vary depending on factors such as size, material, and style. Custom windows, for example, will typically be more expensive than off-the-shelf options.

Remove the old window

Removing an old window is a tricky process, but with the right tools and a careful approach, it can be done successfully. Here is a detailed, step-by-step guide to removing an old bedroom window:

Prepare the Area

Before starting, ensure you have the necessary tools, such as a utility knife, pry bar, putty knife, screwdriver, and hammer. It is also important to wear protective gear, including gloves and eye protection. If your house was built before 1978, be cautious of lead paint. Consider consulting a professional or taking appropriate safety measures.

Remove Storm Windows

If your window has a storm window, start by removing it. Lift it out of its channels or unscrew any screws holding it in place. This will give you access to the main window.

Score the Window Edge

Use a utility knife to score along the edge of the window frame. This will help create a clean separation between the frame and the surrounding structure.

Remove Sash Weights or Springs

Older windows may have sash weights or springs that need to be removed. If your window has weights, cut the cords and let them fall inside the frame. For sash springs, carefully remove them by raising the sash near the top of the window and detaching the springs. Be cautious, as these springs are under tension.

Identify and Remove Stops

Identify any stops on the existing window, including interior, parting, and exterior stops. Depending on whether you're installing the new window from the inside or outside, you may need to remove different stops. Use a utility knife to score where the stops meet the frame, and then carefully pry them off. If they are embedded within the frame, use an oscillating saw to cut them out.

Final Steps

Once the stops are removed, fill any holes with wood filler and ensure the surrounding frame is solid and stable. If there is any damaged or rotten wood, remove it and replace it with new pieces, securing them with screws and wood glue. Additionally, if your window has weight chambers, fill them with insulation before installing the new window.

Removing an old window is a detailed process, and it is important to work carefully and methodically to avoid damage to the surrounding structure and ensure a smooth installation for the new window.

Prepare the frame

Before you begin, place drop cloths on the floor and seal the doorways to prevent dust infiltration. Place a fan in a nearby window and point it outward.

If you are installing a frame for a new window in an existing wall, you must first take down the covering and any insulation on the interior wall to expose the studs. Identify which studs will be cut and which will be kept as king studs. Keep in mind that you will need at least one new king stud, which is the same length as the other existing studs.

The best time of year to frame a window is during the spring or summer when the weather is warm and clear, as you will have an open space in your wall until the project is complete.

For the new frame, you will need 2x4 or 2x6 planks (or other materials depending on the desired frame type and size). You will also need a drill with a screwdriver bit, a combination square and framing square, a framing hammer or nail gun, and a box of industrial staples.

To begin framing, expose the wall studs by removing the interior wall covering and any insulation. Decide which studs will be cut and which will be kept as king studs. Cut two cripple studs, which will support the sill.

Next, create the window header. Cut your 2x6s to the width of the rough-in plus an additional three inches. Nail the two pieces together and attach this assembly to the bottom of your 2x6 assembly.

Now, attach the header to the king studs by nailing the studs into place. Windows have two king studs that form the outermost sides of the window and run between the bottom and top plates.

After this, cut and attach the jack studs. Measure downward from where you intend to place the window vertically, and cut two of your 2x4s to this measurement. Nail these into the king studs so that the jack studs touch the top or bottom plate.

Grab two more 2x4s and cut them for the bottom vertical supports. They will be three inches shorter than the height of your window sill plate. Once cut, nail two to the jack studs and the other two into the centre section.

Finally, attach the sill plate. Cut your last two 2x4s to match the distance between the two jack studs. Nail them together and then onto the top of the four bottom vertical supports. This will serve as a double window sill plate.

Install the new window

Once you have removed the old window, cleaned the window opening, and prepared the space, you can begin installing the new window. Here is a step-by-step guide:

• Apply Flashing Tape: Apply flashing tape to the sill of the window. Ensure it covers the length of the sill and extends up the vertical leg of the stool (the bottom ledge of the interior side of the window). Work the tape into the corner of the stool for a proper seal.
• Check and Level the Sill: Use a level to ensure the sill is level and there is no bowing. If adjustments are needed, use shims to level the sill. Secure them with screws and flashing tape to prevent movement.
• Dry-Fit the Window: Dry-fit the new window into the opening to ensure it fits properly. There should be a small gap around the frame. Set the window aside for now.
• Apply Silicone Caulk: Apply a bead of silicone caulk at the interior head (top) of the frame, the stops, and the sill.
• Place and Secure the Window: Place the window in the opening, resting it against the interior stops and pressing it firmly against the caulk. Use shims to secure the window by placing them at the pre-drilled frame screw holes. From the inside, drive screws into the holes and through the shims.
• Check the Sashes: Ensure that the sashes sit evenly in the frame. If adjustments are needed, use additional shims at the meeting rails (horizontal frame elements where the sashes meet when the window is closed) to adjust the frame.
• Check for Plumb, Level, and Square: Check that the window is plumb (straight up and down), level, and square. Make any necessary adjustments using shims. When everything is aligned, cut off any excess shim material with a utility knife.
• Fill the Gaps with Insulation: From the outside, apply spray foam insulation recommended for windows into the gaps around the window. Do not overfill the gaps. Follow the manufacturer's instructions for the best results. For larger gaps, use backer rod weatherstripping to ensure airtightness and waterproofness. Avoid using batt insulation, which can absorb water.
• Measure Height for Sill Adapter: Measure the height from the bottom of the window to the sill to determine the required size of the sill adapter.
• Cut the Sill Adapter: Use a sharp utility knife to cut the sill adapter to the appropriate width.
• Drill Weep Holes: Drill two weep holes at the bottom of the sill adapter. Weep holes are small openings that help drain water. Lock the adapter onto the window after drilling.
• Protect the Sill Adapter: Use a piece of scrap wood to protect the sill adapter, and gently tap it into place with a hammer.
• Install Exterior Trim: Install exterior trim around the window frame using finish nails. Use a nail set to finish driving the nails to prevent denting the trim.
• Seal the Trim: Seal the edges of the exterior trim with latex caulk, being careful not to cover the weep holes. Fill any noticeable nail holes with wood putty and paint the trim as needed.
• Caulk the Interior: Finish the installation by applying latex caulk along the interior trim.

By following these steps, you will have successfully installed your new bedroom window, ensuring it is secure, functional, and properly sealed.

Frequently asked questions