Staircases in Hammer: they're hard. Let's learn how to make some tricky tricky staircases, k? This tip will work with any staircase dimensions. (Disclaimer: This is for irregular staircase dimensions. It is recommended that you use regular dimensions for all your staircase needs, but this is a catch-all way to handle things.) Step 1) Make a slope in the dimensions that you want your staircase to have. Step 2) Using the Clipping tool, in the top-down view, cut your slope into pieces as so. Step 3) Flip each piece vertically and separately using ctrl+I. It is recommended that you use a 2D side view to select each piece. Shift staircase into place as necessary. Step 4) Celebrate! Don't forget to clip your creation using blockbullets. You can also add fancy side slopes. Most times you should func_detail the entire staircase. Make sure to get rid of those annoying bottom slopes. One way to do this is to create a new brush for each staircase, at the height of the old brush. Remember that new brushes created in the top-down view will retain the height of anything you have selected while making the brush. Players will be stepping all over your creations in no time! Edit) Here's an alternative (better) way to cut the bottom of your stairs: Thank you @DrLambda for the illustration. Thank you @Crash and @Crowbar for clearing up some confusion. @Crowbar's second comment below discusses the difference in faces between different staircase geometry methods.