Responsive Grid Frameworks are very often used in front-end web development for a consistent layout format that is easily implemented by a team of developers. Bootstrap and Foundation frameworks are among the most popular.
These grids are available in PSD format also which can make it easier to keep the mock-ups / wireframes as close to the developed layout as possible.
Below is an example using Bootstrap 3 from Andrew Coss, https://dribbble.com/shots/2051987-FREE-Bootstrap-PSDs
Below, i have created two layouts and added some borders to reflect padding in columns and applied some placeholder content to the existing grid above.