New or replacement windows can be made completely watertight with just a little extra effort by properly installing the sill pan, house wrap and flashing tape.
How to Install Replacement Windows
If you have basic tools and skills you can install your own vinyl replacement windows and save hundreds of dollars in installation charges—for each window.
Illustration: | thisoldhouse.com | from How to Install Replacement Windows
DIY window replacement instructions
installing replacement windows
How to Install Replacement Windows | This Old House
Installing Replacement Windows in a brick house (and removing the old metal ones)
Install Replacement Windows
How to Install Replacement Windows | Step-by-Step | Windows | House Exterior | This Old House - Introduction