How to install dormer windows

A dormer window is very important when you plan on redesigning your attic. It will allow the entrance of fresh air and sunlight. Another upside of the dormer window is that it offers an exit in case of any sort of emergency.

It is mandatory that the dormer window matches the architectural style of the building. There are a lot of types of window materials and qualities out there on the market.

What materials you will need

  • Nails
  • Studs
  • Double plates
  • Stringers
  • Level
  • Timber flat
  • Rafter
  • Tongue-and-groove boards
  • Waterproof coating

Planning the project

Plan every detail to avoid any sort of problems. Decide on the dimensions and location of the dormer window. Be sure to keep the overall aspect of the house when installing the new addition.

How to place the studs

You must cut the attic in the spot where you plan to install the dormer window. Nail two boards that will act as double studs. The studs’ height must be the same as the dormer you want to install, about 6 to 7 inches. The dormer window must be about 75% of the area of the wall. Position the studs and nail them into place.

How to plate the stringers

To enclose the dormer of the attic, frame more studs and then shield the stringers at one end, pointing them to the old rafter. Use a level to assure that their position is perfect.

How to nail the timber and place the rafter

Nail a timber flat to the opening where the dormer window will be and place the rafters along side the stringers. The rafter should be nailed on one end to the plate and the other stringer. The other end should be nailed with the 1×6.

How to outline and cover the roof

Outline the roof opening using the new timber. After that, cut the old rafters add the roof covering using tongue-and-groove boards. To cover the front and sides of the dormer window you must use the same type of wood, used when building the attic, to give it the same aspect.

Last touches

Install the window frame and finish the interior so you can use the window normally. Roll roofing on the sides of the dormer window and install waterproof coating like shingles.


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