How to Trim the Bottom of a Door

Marking and Removing Your Door

Grab a ⁄4–⁄2 in (0.64–1.27 cm) wood shim based on your desired clearance. There should be at least ⁄4 in (0.64 cm) of space between the floor and the bottom of your door. If your door won’t move at all, grab a ⁄2 in (1.3 cm) wood shim. If the door is moving freely but it’s rubbing against your flooring material at certain locations, pick a ⁄4 in (0.64 cm) wood shim. Measure the shim 2-3 times at different locations to confirm that it is perfectly even and flat. Check your hinges before doing this. It’s possible that your door is sticking because the hinges are loose. If you want a larger gap between your door and the floor, you can use a larger shim. The ⁄2 in (1.3 cm) measurement is simply the most common choice. Shims are preferable for this because they’re fabricated with straight edges and they have perfectly-flat bottoms. You can use a standard piece of wood or a book if you prefer, though.

Hold the shim against the bottom of the door and mark your cut twice. Take your wood shim and put it on the ground against the hinge side of the door. Hold the shim in place and mark the top of the shim on your door with carpentry pencil. Repeat this process on the strike side of the door. Then, repeat this process on the back side of the door. You should have a total of 4 hash marks. If your door is getting caught on a specific part of your floor, pull the door out to the area where it is getting stuck and complete this process there. The strike side of the door refers to the side of the door where your handle is. The hinge side is the side where your door meets the wall. You’re basically using the shim to determine how high you need to cut. You can’t measure this cut independently because the floor may not be perfectly flat. This is also why you can’t use a long length of wood to do this; if you do, the cut may not be straight.

Remove the hinge pins from the top and bottom of the door. Grab a flathead screwdriver and a hammer. Stick the head of the screwdriver under the head of the pin at the bottom hinge. Angle the screwdriver at a 45-degree angle, pointing up. Gently tap the back of the screwdriver with a hammer until the pin comes loose. Once it’s sticking up 2–3 inches (5.1–7.6 cm), pull the pin out by hand. Repeat this process for the hinge at the top of the door. Leave the middle hinge for last to keep the weight evenly distributed while you remove the door. You can use a small chisel instead of a screwdriver and a mallet instead of a hammer.

Brace the door as you remove the middle hinge pin. This is much easier if you enlist a friend to hold the door for you. Otherwise, slide a book or shim under the door to keep it from falling down when you remove the last pin. Use your screwdriver and hammer to pop the middle hinge pin out 2–3 inches (5.1–7.6 cm). Hold the top of the door with your nondominant hand to brace it and remove the last hinge pin by hand.

Lift the door out of the hinges and set it on sawhorses. With all of the hinge pins removed, the door is no longer attached to the frame. Grab the door by its sides and slide it out of the doorway. Set the door flat on top of 2 sawhorses.

Use painter’s tape to mark your cut by running it from mark to mark. Pull out a length of painter’s tape that’s slightly longer than the width of your door. Hold the tape over the top of your door and line the left side up with the hash mark you made from your shim. Press the tape down gently and line the other end up with the hash mark on the right. Once your tape is lined up with both marks, press it down and smooth it out with your palms.Tip: The painter’s tape will serve as the straight edge to mark your cut. You can use a level and carpentry pencil to mark the cut before adding painter’s tape if you prefer, but you need to tape the door anyway to keep the wood from splintering, so there’s no point to outlining it first. If there are pleats in the tape or it isn’t laying evenly, pull the tape up and try again. The tape must sit as flat and evenly as possible. If you aren’t sure if the tape is even, use a spirit level to check the straightness of the tape where it marks your cut line.

Wrap additional layers of painter’s tape above the cut line to protect the finish. To keep shrapnel or sawdust from scratching your finish, wrap 4-5 additional layers of painter’s tape above the cut line. Add additional layers of tape above the cut line until you’ve wrapped the 10–20 inches (25–51 cm) above your cut line. You shouldn’t have any tape underneath the hash marks you made with the wood shim. Basically, you’re just using the tape to keep sawdust from scratching your finish. The tape doesn’t need to be particularly thick or layered on top of itself.

Attaching Your Straight Edge

Measure the distance from your saw blade to the edge of the base plate. Grab your circular saw and a measuring tape or level. Hold the edge of the measuring tape or level against the blade of the saw. Calculate the distance from the saw blade to the edge of the saw’s base plate.Tip: The base plate refers to the flat platform that wraps around your saw blade. It is designed to keep the blade flat and stable as you cut. Since the edge of the plate runs parallel to the saw blade, you are going to use the plate and a straight edge to make a perfectly straight cut. Do this outside or in your workshop if possible. If you use your circular saw indoors, you’re going to end up with sawdust flying everywhere.

Set a straight edge parallel to your cut line based on your measurement. Grab a level or wood dowel to use as a straight edge. Put it on top of your door above the cut line. Use your level or measuring tape to transfer the measurement of the saw and plate to the door so that the straight edge rests where the edge of the plate will sit. For example, if the distance between the edge of the saw’s base plate and the saw blade is 2.5 inches (6.4 cm), set your straight edge 2.5 inches (6.4 cm) above the line where the painter’s tape meets the bottom of the door.

Clamp the straight edge in place using bar clamps on each end of the cut line. Get a pair of bar clamps. Hold your first clamp vertically around the straight edge and door. Pull the trigger to close the clamps and hold it in place against your door. Repeat this process on the other side with your second set of bar clamps. Re-measure the distance from the cutting line to the straight edge to confirm that it matches the distance from the base plate to your saw blade. You many need to make minor adjustments once you clamp the straight edge to your door since it may move around a little as you’re clamping it in place. Take your time on this step. The more accurate your straight edge is, the cleaner your cut will be.

Cutting Your Door and Reinstalling It

Put on protective eyewear, a dust mask, and gloves. To keep your hands, eyes, and lungs safe from the sawdust, take the proper safety precautions. Wear a pair of thick, comfortable gloves. Put on a dust mask or respirator. Wear a pair of protective glasses or goggles. Wear hearing protection if you have a high-powered saw. Do not operate a circular saw without wearing your safety gear. Any saw blade designed for cutting wood will work for making this cut.

Hold your saw against the straight edge and inspect your cut line. Take your circular saw and put the plate against the side of your straight edge. Inspect the straight edge to ensure that your base plate is flush. Then, learn forward a little and inspect the guide line on the front of your saw to ensure that it lines up with the edge of your painter’s tape.Tip: If the saw blade doesn’t line up with your painter’s tape, you either miscalculated the distance between the edge of the blade and the edge of the base plate, or you made a mistake when attaching your straight edge. If the saw blade lines up with the tape and your base plate is flush against the straight edge, your cut will be perfect.

Pull the trigger and run your saw blade through your cut. Pull the trigger on the saw on and wait 3-5 seconds to give the blade time to get up to speed. Then, push the saw forward until the teeth hit the side of your door. Let the blade pull your saw through the cut and gently guide the base plate along the straight edge. At the end of the cut, drive the saw all through the edge of the door before releasing the trigger. Keep both of your hands on top of the saw’s handle to steady it as you cut.

Brush away the sawdust and remove the painter’s tape. Set your saw aside and unplug it. Brush the sawdust away with a dry cloth or paint brush. Then, unravel all of the painter’s tape, starting with the lengths of tape closer to the center of your door. Work your way down to the cut line and remove all of your tape before discarding it. If there are any pieces of splintered wood sticking out from your cut line, gently brush them away. The painter’s tape should prevent this from happening, though. You can use compressed air instead of a brush if you prefer.

Hang your door on the hinges the same way you took it off. With your door trimmed, re-hang the door on your hinges. Put a book under the door to stabilize it and raise it up, or enlist a friend to hold it for you. Slide the middle hinge pin through the middle hinge and use a hammer or mallet to gently tap it back into place. With your middle hinge installed, repeat this process for the top and bottom hinge. Your door will now have a ⁄2 in (1.3 cm) of clearance at the bottom!