How to Install a Storm Door in 8 Steps

You must accurately measure your door frame to ensure you buy the right size storm door. Using a tape measure, take two sets of three measurements:

• Measure from the top of the frame to the threshold on the left and right and in the middle

• Measure from left to right from the top, center, and bottom of the frame

Write down the smallest measurement from each set and purchase a storm door in that size. Home improvement centers sell prehung storm door kits in various standard sizes, typically between 30 and 36 inches wide. If your door frame is wider, consider ordering a custom door or an extender kit to fill the space between the storm door and frame.

Hold the hinge rail (a storm door part also known as the hinge-side z-bar) tight to the trim on whichever side you’ve chosen to place the door hinge. Drive a screw into the top hole of the rail, leaving a ⅛-inch gap between the head of the screw and the trim. Remove the hinge rail, leaving the screw in place.

Prepare by laying your door on a stable surface or resting it on dual sawhorses. Start with your hinge rail against the opening on the door's hinge side. With your hacksaw, cut the hinge rail to match the height of the door's opening. Be sure to create a slight slope on the bottom that will accommodate the slope of your door sill. Finally, screw the hinge rail to the door.

Add the door sweep to the bottom of the storm door. Fit it to size by snipping any excess sweep. Weatherstripping should even cover the door sill's width. If extender rail caps are provided, remove them from the bag to note markings for "left" and "right." To place them on, use a "squeeze and shove" technique that allows them to fit over the bottom corners.

This step may be easier with a partner to help you lift the door. Hang the hinge rail onto the placeholder screw and tighten it to hold the door in place. Use a level to ensure the door is plumb and level, and adjust the screw if needed.

With the door level, drive screws along the inside of the hinge rail to fasten it to the frame. If you have a rail cap, slide it down to the door sill. Fasten the outside of the hinge rail to the door trim. Make sure the door can open and close freely, then measure and cut the handle-side z-bar the same way you cut the hinge rail. Fasten it to the other side of the door frame with screws.

Also called the drip cap, the rain cap is a narrow rail that sits across the top of the door frame to stop rain from leaking between the storm door and entry door. Line it up to the edge of the door’s hinge rail, holding it tight to the trim. Attach it by drilling one or more screws through it. Install the latch rail tight along the edge of the drip cap and fasten it with screws as well.

Some prehung storm doors come with handles and locksets, while others require separate hardware. Follow the instructions provided with your storm door to drill holes in the door for the latch. You may have a drilling guide, which you can snap to the outside of the door to show where holes should go.

Slide the lock body into the holes and fasten it with a screw. Place the face plates on either side of the door, push the handle rod through, and then secure both handles with additional screws. The latch and deadbolt should be able to extend into the latch opening. If not, use a chisel to open up enough space in the door trim.

The door closer adjusts the speed at which your door will swing shut. Install your storm door closer according to the manufacturer’s instructions. You’ll add one closer bracket to the hinge side door jamb and the other bracket to the door. Loosen or tighten the closer to adjust the door speed. If your model comes with a safety chain, mount it so the door can open a full 90 degrees.