How to Hang a Slab Door

Fitting Your Slab Door to the Doorframe

Measure the doorframe opening if you don’t have the original door. If you are hanging a slab door in a new doorframe, or in an existing doorframe but you don’t have the original door, use measuring tape to measure the size of the doorframe opening. Place the end of the measuring tape in the top corner of the doorframe opening and pull down. Stop the measuring tape ⁄8 inch (0.32 cm) above the ground to leave a clearance under the door. Then, measure the inside width of the doorframe opening, leaving a ⁄16 inch (0.16 cm) clearance on either side. Use these measurements to mark the size of the doorframe opening on the slab door with a pencil. If your floor is carpeted, leave a ⁄4 inch (1.9 cm) clearance at the bottom of the door instead of a ⁄8 inch (0.32 cm) clearance. This will allow more room for the door to swing open without getting caught on the carpet. When marking your measurements on the slab door with a pencil, use a ruler to make sure that you draw a straight line. This will allow you to make a clean, even cut when you plane or cut it down with a circular saw.

Align the old and new door slabs if you have the original door. If you are hanging a slab door to replace an existing door and you still have the original door, you can measure your new door slab to fit the frame by aligning it with the old door. To do this, place both doors next to each other on the thin, long sides with the hinges on the old door facing up. Align the doors so that the tops are even, then use a clamp to hold the doors together. If the old and new slab doors are the same size, you can leave the new slab door as is. If the new slab door is longer or wider than the old door, use a pencil to trace the shape of the old door on the new slab door.

Trim the slab door to fit the doorframe. If your slab door is longer or wider than the old slab door or the measurements for the doorframe opening, trim it down to size. If less than ⁄8 inch (0.32 cm) needs to be trimmed from the bottom and/or sides, plane the door to get it down to size. If you need to trim more than ⁄8 inch (0.32 cm), use a circular saw to trim the door down to the size of your pencil-marked measurements.

Attaching the Door Hardware

Measure the hinge placement on the door and doorframe. If you have the original door, re-clamp it to the new slab door if you unclamped them to plane or cut. Use a ruler to create a straight line from the tops and bottoms of the hinges, then use a pencil to mark the location across the new door. If you don’t have the old door, use measuring tape to measure the location of the hinge attachment on the existing doorframe. If you are using both a new doorframe and a new slab door, attach the hinges so that the top hinge is 7 inches (18 cm) from the top of the door frame and the bottom hinge is 11 inches (28 cm) from the bottom of the door frame.

Cut the hinge mortises on the slab door. Once you have marked out where the hinges will go, place one of the hinges in its specified location. Using a utility knife, score a line around the hinge. Measure the depth of the hinge and place it aside. Then, use the utility knife to draw straight notch marks at the depth of the hinge across the interior of the hinge area. Use a chisel to pick off the notches one by one until the interior hinge area a shallow indention (called a mortise) to allow for the hinge to lay flush to the door. Repeat this process to cut the mortise for the other hinge.

Attach the hinges to the slab door. Place the hinges on their designated spots on the door. Using a drill, drill the screws into place to attach the hinges to the slab door. Most door hinge kits come with the screws that you will need. If they don’t, you can buy them separately at any hardware store. If you need to buy the screws separately, bring the hinges with you to the store so you can make sure you get the right size.

Mark the location for the doorknob if there isn’t a doorknob hole. If you still have the original door, you can use the old door as a template again by lining the doors up and using a ruler and pencil to mark the doorknob location. If you don’t have the original door, use measuring tape to measure 36 inches (91 cm) up from the bottom of the door. Mark the location with a pencil. Repurposed doors and some new slab doors may already have a hole cut for the doorknob. If this is the case, you can skip this step. 36 inches (91 cm) is the standard height for most doorknobs. You can adjust this, however, depending on your preference, as well as to suit the particular size of the door.

Install the doorknob onto the slab door. Once you have marked the location of the doorknob, you can go ahead and install the doorknob by drilling the holes for the doorknob and lockset and inserting them into their specified locations. How you will drill the holes and affix the doorknob will depend on the type and style of doorknob you choose, so make sure to follow the installation instructions for your specific doorknob. If you are using a repurposed slab door, you can either use the existing doorknob or replace the doorknob with the new one that fits into the existing holes.

Hanging the Slab Door in the Doorframe

Cut mortises for the door hinges if your doorframe is new. If you are attaching your slab door to a new doorframe, you will likely need to cut mortises for the door hinges. First, mark the spot on the door where the hinge will go by drawing the outline with a pencil. Measure the depth of the hinge and place it aside. Then, use the utility knife to mark around the perimeter of the hinge line, as well as straight notch marks at the depth of the hinge across the interior of the hinge area. Use a chisel to remove the notches to make room for the hinge to lay flush. If you are attaching your slab door to an existing doorframe, the mortises will already be cut and you can skip this step.

Attach the slab door hinges to the doorframe. Move the door to its location inside the doorframe. Align the hinge to the hinge mortises on the doorframe. Then, use a drill to screw the hinge into the doorframe. You may need to use wooden shims to help hold the door tightly into place while you drill the hinge screws into place.

Check the fit of the door. Once your slab door is attached the doorframe, double check the fit of the door by opening and closing it a few times. This will help you make sure that the door is in working order before you paint or stain.

Paint or stain the slab door to finish. Now that you have hung your slab door, you can paint or stain the door to suit your taste, or to touch up any nicks that may have occurred during the installation process. You can also paint the door frame if you choose. While you can paint or stain the slab door before hanging it, you may end up scratching or chipping the paint during the process. Therefore, it could save you some time to do this at the end.