How to install a window?

To learn how to install a replacement window or assemble a window on new masonry, check the videos we selected below and read our advices for your installation.


  • When installing a window on an existing opening, it's possible to keep the original frame if it's sound and solid, in order to avoid any modification in the walls.
  • Always follow safety guidelines and the technical manual.
  • Regularly check the squareness and the perpendicularity.

JELD-WEN- Step by step guide to replacing a window

Tools and materials:

  • Protective equipment
  • Measuring tape
  • Tarp
  • Drill
  • Electric screwdriver
  • Saw
  • Stanley knife
  • Hammer
  • Chisel
  • Spirit level
  • Silicone sealant

Key steps:

  1. Prepare the work area and protect all surfaces.
  2. Make sure you've ordered the correct size before removing the old window.
  3. Carefully remove all the packaging of the new window.
  4. Unscrew and remove the sashes.
  5. Cut down the side of the window to remove the fixed sash.
  6. Remove the transom.
  7. Take away all fixed sash fittings to safely remove the bottom sash.
  8. Score down the internal finish to break the finish away from the frame.
  9. Remove the remaining elements of the frame.
  10. Remove the sill.
  11. Conceal or remove the existing fixing straps.
  12. Make sure the opening is completely clean.
  13. Place the window in the opening to make sure it fits.
  14. Make sure the window is level.
  15. Fix the window in place.
  16. Check the frame is square and level, plumb and operates correctly.
  17. Run silicone sealant down the sides of the frame.
  18. Repeat for the interior junction between the existing finish and the new frame.

Jeld-Wen Vinyl Replacement Window Installation- How To

Tools and materials:

  • Measuring tape
  • Hammer
  • Drill
  • Spirit level
  • Screwdriver
  • Scissors
  • Silicone sealant
  • Insulation material

Key steps:

  1. Verify the existing window frames are square, level and plumb.
  2. Measure the minimum opening width and height of the existing frames.
  3. Report the smallest width first then the smallest height for each existing window frame.
  4. Inspect the new windows for damage.
  5. Score the interior stops and carefully remove.
  6. Cut the cords running to the lower sash.
  7. Remove the lower sash.
  8. Score and remove the parting stops.
  9. Cut the cords running the upper sash. Remove it.
  10. Remove or hammer back the pulleys into the frame.
  11. From the interior, apply a large bead of silicone sealant onto the exterior blind stop.
  12. Set the new window into the existing frame.
  13. Shim the side jambs.
  14. Fasten the window through the shims.
  15. Install vinyl plugs to cover the screw holes.
  16. Snap of the exposed portion of the shims.
  17. On the interior, insulate between the existing frame and the new window frame.
  18. Apply backer rod then sealant between the new and existing frames.
  19. Replace the interior stops.
  20. On the exterior, apply a sealant between the new window and the exterior blind stop.

UPVC Double Glazing Window Installation

Tools and materials:

  • Dust sheets
  • Hammer
  • Chisel
  • Spirit level
  • Silicone sealant
  • Drill
  • Electric screwdriver

Key steps:

  1. Protect the areas around the window installation.
  2. Remove the old window.
  3. Ensure structural stability.
  4. Remove the old frame.
  5. Check the level.
  6. Apply silicone sealant to the window sill.
  7. Assemble the window and the frame.
  8. Apply silicone sealant and secure the installation with screws.
  9. Install the external and internal trims.
  10. Remove all excess silicone.
  11. Hide the screws with caps.

10 essential steps for a proper window installation

This video precisely points out the particular steps you need to check during a professional installation, to make sure the work is well done.

This article to learn how to install a window was written by Cécile Lessard

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