Home Improvement

How do you insulate the bottom of a bay window?

How do you insulate under a bay window?

To insulate bay windows:

  1. Cut foam insulation board to fit the underside of the bay window seat.
  2. Attach the board to the seat.
  3. Cover the insulation board with a piece of plywood.
  4. Fasten the piece of plywood in place.

Should a bay window be insulated?

Most people only insulate under the bay window. Side walls also need insulating if no cavity exists. Also consider the space above your bay window, such as inside the cladding.

How do you insulate a bay window for winter?

Install fiberglass or cellulose insulation in the joist bay. Install a final piece of XPS or Polyiso on top of the fiberglass or cellulose. Be sure to seal this piece to all the framing and foam. After all those steps you can install the deck sheathing.

How do you insulate under windows?


  1. Apply Window Film Insulation. Prep your window for the film by thoroughly cleaning and drying the window. …
  2. Caulk Around Gaps and Cracks. …
  3. Apply Weatherstripping Around the Window. …
  4. Insert Spray Foam in Openings. …
  5. Hang Energy Efficient Window Treatments (Thermal Curtains) …
  6. Place Horizontal Draft Stoppers.

Why is my bay window so drafty?

When cold air works its way from the outside to the inside of the single-pane window, “the cold air moves down off the window, creating convection–or drafting,” says Arasteh. “Even if a window is properly sealed, if it’s single-pane, you will feel that drafting.”

What do you put in a bay window sill?

Cushions. A versatile way to decorate the ledge of a bay window is to cover it with a large cushion. This turns the ledge into a comfortable place to sit, and gives you an area to look out your window more easily.

How do you insulate windows from the outside?

You might consider purchasing a window insulation kit to install on the exterior portion of your windows.