Measure the Existing Transition
Thresholds can occur at doorways, changes in flooring or transitions between rooms. The visible height should be measured along with the floor levels on both sides.
The goal is not simply to remove material. The finished transition still needs to protect floor edges, allow the door to operate and avoid creating a new gap or unstable joint.
Reduce Height Without Creating New Problems
Some thresholds can be replaced with a lower transition profile. Others exist because the adjacent floors are genuinely different heights.
If the underlying floor needs leveling or a door must be modified, that should be included deliberately. Exterior thresholds also have water-management needs and should not be treated like an interior transition.
Threshold Modification vs Doorway Widening
A lower threshold improves one part of the passage while Doorway Widening changes the clear width of the opening.
When several circulation barriers need to be addressed together, Aging-in-Place & Accessible Remodeling is the better umbrella. No threshold change should be presented as a medical recommendation or guarantee of accessibility for every user.