How to Install an Interior Door: Complete Installation of the Door Frame and Hinges
Installing an interior door is a carpentry job within the reach of a careful DIYer, provided you follow a few simple rules of measurement and levelling. From choosing the door, installing the frame, fixing the hinges and adjusting the door leaf, each step demands method. In this complete guide, we show you how to install an interior door from A to Z, giving you the exact measurements, the essential tools and the pro tips for a perfect result.
Choosing your interior door and taking the measurements
Before getting out the tools, you need to know the exact size of your opening. Standard interior doors measure 63, 73, 83 or 93 cm wide and 204 cm high, but made-to-measure formats exist. Measure the width and height of your opening at three different points and keep the smallest dimension: it is this that determines the purchase. Plan a 2 cm gap between the masonry opening and the frame for a traditional installation, which is simpler for a beginner.
The materials and tools you need
- A pre-hung or raw door with its frame (complete casing)
- A spirit level of 1 m minimum and a laser level if possible
- Wooden wedges (battens of varying thickness)
- A jigsaw or miter saw, a hammer
- Wood screws or nails, a drill driver
- Polyurethane foam, so-called "PU foam"
- Adjustable plastic packers, a clamp
- A carpenter's pencil, tape measure, square
Preparing the opening and the floor
The opening must be sound, clean and vertical. Remove the old traces of protruding plaster or mortar and dust carefully. Check that the floor is clean and level: the door will sit on it with a 1 cm gap at the bottom to let air pass and allow for irregularities. If your floor slopes, place a wedge at the lowest point before installing the frame.
Installing the door frame step by step
- Dry-assemble the jambs and the head of the frame, without screwing, to check the squareness.
- Place the frame in the opening and slide a wedge under the hinge-side jamb to give the 1 cm gap under the door.
- Set the hinge jamb perfectly vertical with the spirit level, then pack the bottom and top firmly.
- Check the diagonal: the two diagonals of the frame must be equal (tolerance 2 mm), otherwise correct by tapping gently.
- Fix the frame temporarily with nails or screws through the wedges, starting with the hinge jamb.
- Check the level and squareness again, then screw definitively at the top, middle and bottom of each jamb.
Fixing the hinges and hanging the door leaf
The hinges (or hinge plates) are usually fitted at the factory on pre-hung doors: all that remains is to screw the door leaf onto the frame. Start by laying the door on two trestles, hinge side facing up. Screw the hinges into the pre-drilled recesses in the edge of the door, then offer up the leaf with help to hold the weight. Fit the hinges onto the hinge plates of the jamb, starting at the top. Close it gently and observe the gaps.
- Check that the door is level: the leaf must not touch the floor.
- Check the alignment of the hinges: the pin of the hinge plates must be properly in line.
- Test the closing: the door must come and press against the stop without effort.
- Adjust the hinges with the eccentric screw to adjust the leaf horizontally and vertically.
Packing and injecting the PU foam
Once the door is in place and well adjusted, insert plastic packers all around the frame, 5 cm from the corners and level with the fixing points. Then fill the gap between the frame and the wall with polyurethane foam. Spray in small passes of 3 cm maximum thickness starting at the bottom, because the foam expands and can distort the frame if you put too much in. Let it dry for 4 to 6 hours before trimming the excess with a utility knife.
The mistakes to avoid
- Neglecting the level of the hinge jamb, which condemns the door to rubbing or staying open.
- Forgetting the 1 cm gap under the door: once the carpet or wooden floor is laid, the leaf rubs.
- Injecting too much PU foam at once: it expands and distorts the frame, impossible to correct afterwards.
- Screwing the door directly without checking the squareness of the frame diagonals.
- Carrying a heavy door leaf alone: better to be two to avoid bending the hinges.
Installing an interior door requires patience, but the result is immediately visible and rewarding. By taking care with the verticality of the frame, adjusting the hinges precisely and taking the time to pack before injecting the foam, you get a door that closes effortlessly and lasts for years. If the opening is very distorted or the wall is in poor condition, do not hesitate to call in a carpenter: the cost of the installation remains reasonable compared with the risk of damaging a brand-new door leaf.