Can you trim bottom of door without taking it off?

Quick Answer

Yes, it is possible to trim the bottom of a door without completely removing it. This can be done by either undercutting the door or planing it. Undercutting involves cutting a notch out of the bottom edge of the door so it can clear the flooring surface. Planing involves using a power planer to shave off thin layers from the bottom of the door until the desired clearance is achieved. Both methods allow the door to be trimmed in place.

What Tools Are Needed?

To trim a door bottom while still hung, you will need the following tools:

• Pencil
• Utility knife
• Carpenter’s square
• Electric/power planer or jamb saw
• Safety glasses and dust mask
• Vacuum and rags for cleanup

The specific tools needed will depend on whether you are undercutting or planing the door. Undercutting just requires a pencil, utility knife, square, and saw like a jamb saw to cut the notch. Planing requires a power planer but can be done freehand rather than needing to mark and cut a specific notch area.

How Much Can Be Trimmed Off a Door?

When trimming a door while hung, it’s recommended to remove between 1/8 to 1/2 inch from the bottom. Removing 1/8 inch is usually sufficient if you just need a little extra clearance over the flooring surface. Up to 1/2 inch can be removed for thicker floor surfaces like tile, stone, or hardwood.

Removing too much from the bottom of the door could impact its structure and rigidity over time. It also may not look aesthetically pleasing if there is a large gap under the door. Stick to small incremental trims, testing the fit as you go until the door clears the floor surface.

Step-by-Step Undercutting Instructions

Here are the step-by-step instructions for undercutting a door while it’s still hung:

1. Measure the clearance needed under the door using a straightedge and pencil. Mark the bottom edge of the door where the flooring clearance is needed.
2. Set the height of the utility knife blade to match the clearance measurement.
3. Open the door at a 90 degree angle. Use a carpenter’s square against the bottom edge to guide the utility knife vertically as you slice into the door.
4. Repeat slicing into the bottom edge of the door along its full width where clearance is needed.
5. Place a nail stop just above the slice line to prevent the jamb saw from cutting too far up the door edge.
6. Use the jamb saw to carefully cut along the sliced groove, trimming away a notch from the door bottom edge.
7. Test fit the door and trim deeper if additional clearance is needed.
8. Sand or plane the cut edge smooth and vacuum away debris.

The advantage of undercutting is being able to remove just enough to clear the specific flooring height. It does not require removing material along the door’s full length. However, it creates an obvious notch on the bottom edge.

Step-by-Step Planing Instructions

Here are the step-by-step instructions for planing a door bottom:

1. Lower the planer blade carriage until it extends just 1/16 to 1/8 inch from the sole plate.
2. Open the door fully and brace or clamp it to prevent shifting while planing.
3. Run the planer over the door bottom, working in the direction of the wood grain. Take very light passes.
4. Test fit the door and take additional light planing passes until the needed clearance is reached.
5. Reset the planer blade to take finer finishing passes. This leaves a smooth surface.
6. Vacuum debris and wipe down the door bottom with a dry cloth.

The advantage of planing is being able to gradually and evenly remove material the full width of the door. This avoids creating a visible notch. But it requires removing more material than just undercutting for clearance.

Planing vs Undercutting: Which is Better?

So which method is better for trimming a door while hung – planing or undercutting? Here’s a comparison:

Method	Pros	Cons
Undercutting	Removes the least material needed Maintains door structure	Creates visible notch on edge Limited to small trims
Planing	Thin material removal is gradual Leaves smooth, even edge	Must remove more material Can reduce rigidity over time

As you can see, undercutting is best for minor trims and planing works better for thicker floor surfaces where maximum clearance is needed. Consider how much needs to be removed and the visible results when choosing between these two methods.

Tips for Trimming a Door In Place

Here are some additional tips to follow when trimming the bottom of a hung door:

• Work slowly and make minor adjustments to avoid removing too much material at once.
• With planing, always plane in the direction of the wood grain for best results.
• Open and close the door as you get close to the needed clearance and test with a straightedge.
• Use a vacuum, rags, and drop cloths to contain dust and debris.
• Consider undercutting near the knob side if clearance is only needed in one area.
• Apply new finish or paint to the trimmed door bottom to seal and protect the exposed wood.

Taking it slowly and checking the fit often will help prevent over-trimming. A fresh coat of finish will keep the modified door bottom looking good.

When to Remove the Door Instead

In some cases, it’s better to completely remove the door instead of trimming it in place:

• If the flooring height difference is greater than 1/2 inch
• If the door also needs its width shortened from the sides
• If there is existing damage or rot on the bottom edge
• If you need to work on the hinges or door slab itself
• If major sanding or planing is needed for a smooth surface

Taking the door down provides more access for alterations and repairs. But it can take more time and work to remove and rehang the door.

Conclusion

Trimming a door while it is still hanging can be done through careful undercutting or planing of the bottom edge. This allows you to gain clearance over new flooring without the hassle of completely removing the door. Just be sure to take your time, remove thin layers, and frequently test the fit. Consider whether it’s easier to just take the door down for more extensive trimming or other repairs. With some patience and the right tools, it is generally possible to subtly trim an interior door in place and achieve the perfect floor clearance.