How Do I Take Apart a Casement Window?

Wanda Thibodeaux

Casement windows can provide increased draft resistance and energy efficiency, but sometimes these windows need replacing. When it's time to replace a casement window, following a simple order of operations can make the job easy.


Replacement of a casement window requires a hammer, cat's paw, pry bar, shingle thief and a putty knife or flathead screwdriver. If your hammer is equipped with a nail removal claw and the end of it is very thin, you may be able to do this without a pry bar, since you may be able to get the edge of the claw under the window material, but the pry bar may give you better leverage. Wear work gloves and protective eye and face gear to prevent splinters and nail edges from accidentally penetrating the skin, and to prevent dust inhalation.

Start Inside

Most casement windows are installed from the outside, so you need to remove everything holding it in place inside before the window will pop back out. Starting in one corner, fit the putty knife between the molding and extension jam and gently tap the top of the knife with the hammer as you work your way around. This will separate the molding from the jam enough so that you can pry it off with the pry bar. When the molding is off, use the pry bar to work the extension jam off. Be careful not to use too much force, and watch your leverage angle when you are prying the molding and extension jam off so that you do not damage the wall.

Move Outside

Once you've taken off the molding and extension jam inside, move outside to remove the shingles along the window. Working from the top row of shingles down, work the shingle thief up under each shingle and tap the bottom of the shingle thief. This will let the shingle thief cut through the nail holding the shingle in place. If you can, save the shingles; you can reattach them after you install a new window, provided the shingles are in good shape after removal. Remove any nail remnants that don't come up with the shingles as you go, or just hammer them down. (They can't be left sticking out anyway, since they'd interfere with putting the shingles back on.)

Removing the Window

Once all the shingles are off, locate the nails holding the window in place. Pull them out using your cat's paw and hammer. Always leave the top nail for last so that the window doesn't fall out on you. When you are ready, remove the top nail and ease the window out of the frame. If you can, have someone hold the window up from the outside as you remove the last nail, just in case it wants to slip out before you can get a solid grip on it.