How to Fit Velux Skylights

Updated February 21, 2017

Velux offers many different models of skylights. They are available in two basic types: fixed, which do not open, and venting, which can be opened. Skylights add natural light and warmth to a space that lacks enough windows, and when properly positioned, also impart design interest to a room. They come in various sizes and are installed between the trusses (rafters) in the roof. Fitting the skylight properly is an extremely important part in the installation process. The unit must be the right size to fit the opening between the rafters.

Climb a ladder to the roof and decide upon a suitable place for the skylight installation. Pick an area of the house that does not have many windows or receives relatively little direct sunlight. The skylight position should be between rafters.

Remove the shingles or other roofing material from the area where you intend to install the skylight. Use a pry bar and nail puller remove both the covering and roofing nails to expose the roof sheathing. Pull on the window clips to remove the skylight from the frame and set the frame on the cleared sheathing.

Measure and mark the outline of the window on the sheathing leaving one inch extra on all four sides. Cut along the mark with a reciprocating saw to remove the plywood sheathing and create a hole in the roof just larger than the skylight frame.

Measure, cut and install 2-by-3 lumber to create a rough frame that fits within the perimeter of the opening so the skylight can fit onto it. Attach the rough frame to the sides of the rafters with four inch wood screws. Attach the provided metal brackets with screws to the corners of the frame and set the frame in the opening.

Fit the skylight frame snugly in place and screw the brackets into the roof at each corner. Set the skylight window section into the frame and reinstall the clips that hold it in place. Install the provided flashing along the edges between the roof surface and the sides of the skylight according to the manufacturer's directions. Check the roof window to make sure it fits properly into the opening.


Always wear safety goggles when working with a reciprocating saw to protect your eyes. Be extremely careful when positioning, climbing or working on a ladder.

Things You'll Need

  • Ladder
  • Pry bar
  • Safety goggles
  • Marker
  • Reciprocating saw
  • 2-by-3 lumber
  • Tape measure
  • Power or hand saw
  • Electric drill
  • Wood screws
  • Flashing
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About the Author

Alexander Callos began writing in 2005 for "The Lantern" at The Ohio State University and has written for various websites, including Bleacher Report, Top Ten Real Estate Deals and Columbus Sports. He has published articles for CBS Sports, and other websites. He graduated in 2007 from The Ohio State University with a bachelor's degree in public affairs journalism.