1 – Locate the problem areas
This step will depend on whether you are trimming an existing interior door, or you are planning to fit a new door. If it is a new door, skip to section two of this guide. If you are trimming an existing door, you will need to find where the sticking and binding areas are. You can use either 1) Identify differences in the gaps around the door, or 2) Look for areas on or around the door that show signs of rubbing, or 3) Open and close the door to locate trouble areas. Once you identify the problem areas, mark with the pencil. It is recommended to leave a gap of 4mm to 8mm at the top and bottom of the door for a perfect finish; this will depend on the type of flooring you have.
2 – Remove the door from the frame
If your interior door has removable hinge pins, you can pop them out using a screwdriver or large nail to remove the door. If not, you will need to unscrew the hinges from the door rather than from the door frame. It is also a good idea to tape screws and pins to the hinges to avoid losing them.
3 – Lay and secure the door on a workbench
Lay the door on a stable surface such as a workbench and secure it using clamps or straps. Ensure that the door is 100 percent secure, so it does not move when you are planing the door.
It is also important to protect the surface around the area you are planning to trim which will help prevent scuffs or marks in the event tools or equipment bang the door.
4 – Plane or saw the door
Depending on how much of the interior door you need to trim, you can either plane or saw off the marked areas at the top and bottom of the door. It is important that you adjust the plane to an angle that removes wood gradually and evenly, and you run the plane in the direction of the wood grain for a more smooth, perfect finish.
While it can be a hassle removing and rehanging the door repeatedly, it is always the best practice to prevent taking off too much wood. Fix the hinges into place temporarily with a single screw. Check the door closes flush, and the gap between the door edges and frame are around 2mm (might be slightly different at the bottom depending on the type of flooring you have) and the door is not jamming nor sticking.
5 – Finish the trimmed, exposed areas
Before applying paint or stain to the trimmed, exposed areas, we recommend sanding the exposed wood first to smooth it out. Start by firstly using a rough piece of sandpaper (around 40-60 grit) to remove large pieces of unwanted wood, and then fine sandpaper (80-120 grit) to create a smooth surface.
Apply stain to a stained interior door, and primer and paint to a painted door. Wait for it to dry; if you are happy with the finish, you are now ready to rehang the door. More information about finishing a door can be found here.
6 – Rehang the door
Position the interior door against the door frame and ensure the door is at the correct height; using a door wedge for stability will help with this part. Fix the hinges into place and make sure to tighten the hinge screws properly to prevent wilting.