On this page
Door installers and finish carpenters hang new interior doors, swap hollow slabs for solid ones, convert swinging doors to pocket, barn or bifold doors, fix doors that rub or won't latch, and replace the door between an attached garage and the house, which has its own code requirements. The doors are then painted or finished, on site or before they are hung.
This page covers the main types of interior doors, hollow-core versus solid-core construction, prehung versus slab doors, sound and privacy, the rules for the garage door into the house, door swing and clearances, and painting and finishing.
Types of interior doors: panel, flush, pocket, barn, bifold and French doors
- Panel door: raised or recessed panels set in a frame of rails and stiles, from traditional profiles to a flat shaker style.
- Flush door: a smooth, flat face that suits modern interiors and is the easiest to paint evenly.
- Pocket door: slides into the wall and frees floor space in bathrooms, pantries and tight hallways, at the cost of weaker sound control and a frame built into the wall.
- Barn door: slides along an exposed rail on the face of the wall, a decorative choice that needs clear wall space beside the opening.
- Bifold door: two or more hinged panels that fold against each other on a top track, common on closets and laundry alcoves.
- Interior French door: glass panes in a wood or composite frame, used to close off a dining room, office or living room while letting light through.
Hollow-core vs solid-core interior doors
What is inside the slab matters more than its face. A hollow-core door has thin skins over a light cardboard or honeycomb grid, a solid-core door is filled with a dense composite, and a solid wood door is wood throughout. The difference shows in weight, sound, feel and how well the door survives everyday knocks.
- Hollow-core: light, easy to hang and economical, fine for closets and low-traffic rooms, but it sounds hollow, lets noise through and dents or punctures easily.
- Solid-core: heavier, quieter and more solid to the touch, a good choice for bedrooms, bathrooms and home offices, as long as the hinges and jambs are sturdy enough.
- Solid wood: the warmth of real wood and the easiest to repair, but it moves with seasonal humidity and must be sealed on every edge.
- Moulded skins: most panel doors now have a moulded composite face, so hollow and solid doors can look identical; lift one to feel the difference.
Prehung or slab interior door: which one to order
A prehung door arrives already hinged in its own frame, with the hinge mortises and lock bore done at the factory. A slab is the door alone, to be fitted into the frame you already have. The choice depends mostly on the state of that frame and on how much trim you are willing to take off and redo.
- Prehung: the right choice for a new opening, or when the old jamb is damaged, out of square or the wrong depth; the casing comes off and is reinstalled or replaced.
- Slab: keeps the existing frame and trim, which matters in older homes with original mouldings worth preserving.
- Slab fitting: the door must be trimmed to size and its hinges and latch mortised to line up with the old frame, work that takes a practised hand.
- Jamb depth: a prehung frame must match the wall thickness, so plaster walls or walls with extra layers of drywall may need wider jambs or extensions.
Interior door sound and privacy: keeping noise between rooms down
Sound takes the easiest path, and a door is usually the weakest part of the wall it sits in. The gaps around and under the slab often let through more noise than the door itself, so a quieter room needs both a denser door and a better seal.
- Choose solid-core slabs for bedrooms, bathrooms and home offices, where privacy counts most.
- Add seals on the door stops and a bottom sweep or drop seal, but keep a path for air to return to the heating system, and ask about a transfer grille if the room has a supply vent and no return.
- Avoid pocket, barn and bifold doors where quiet matters, since their gaps are hard to seal.
- Pair a good door with insulation in the wall for a home office or media room, since a solid door in a hollow wall won't give much quiet.
- Use privacy locksets on bedrooms and bathrooms that can be opened from outside with a simple tool, a real help with young children.
The door between an attached garage and the house: code requirements
The door from an attached garage into the house is not an ordinary interior door. Under Article 9.10.13.15 of the National Building Code, as reproduced in provincial codes such as British Columbia's, it must be tight-fitting and weatherstripped to provide an effective barrier against gas and exhaust fumes, and it must be fitted with a self-closing device. The doorway may not be located in a room intended for sleeping. The Ville de Québec's guide to attached garages sets out the same requirements.
That article is about keeping fumes out; it does not itself call for a fire-rated door. Other requirements can apply in a multi-unit building or under local rules, so ask your municipality what applies before replacing the door, and choose a solid, insulated, weatherstripped unit rather than a hollow interior slab.
- Keep the self-closer working, since a door propped open or a disconnected closer defeats its purpose.
- Replace worn weatherstripping and the bottom seal so fumes can't slip around the door.
- Don't cut a pet door or a vent into this door, since either one opens a path for fumes.
Planning interior door swing and clearances
- Swing into the room: doors usually open into the room they serve, so they don't block the hallway or hit someone walking past.
- Open against a wall: the door should rest flat against the nearest wall, not across a light switch, a closet or a heat register.
- Small bathrooms: an inward-swinging door can be blocked if someone falls against it, so an outswing or pocket door can make help easier to reach.
- Neighbouring doors: in tight hallways, check that two doors can't collide or hit the same spot when both are open.
- Easier access: wider openings and lever handles make moving through the house easier with a walker, wheelchair or stroller, worth planning for when renovating to age in place.
- Floor changes: new flooring, thick carpet or a threshold may mean the door has to be trimmed at the bottom.
Painting and finishing interior doors
Interior doors are handled far more than walls, so their finish has to be tougher. Doors come primed, prefinished at the factory or unfinished; primed doors are the usual starting point for paint, while a stained look calls for a wood veneer or solid wood door.
- Use a durable paint made for doors and trim, usually in a satin or semi-gloss sheen that stands up to hands and cleaning.
- Paint doors off their hinges, laid flat or hung on a rack, to avoid drips and get an even coat on the edges.
- Seal the top and bottom edges as well as the faces, especially on bathroom and laundry room doors where humidity runs high.
- Let the paint cure before rehanging the door and closing it against the stops, or it can stick and peel.
- Consider new hinges and handles in a matching finish at the same time, which makes repainted doors look brand new.
Interior Doors: frequently asked questions
Is a solid-core door worth it for bedrooms?
For bedrooms, bathrooms and home offices, usually yes. A solid-core door blocks noticeably more noise than a hollow one and feels more substantial, though its weight calls for sturdy hinges. For closets and utility rooms, a hollow-core door is generally enough.
Why does my interior door rub or refuse to latch?
Loose hinge screws, a house that has settled or seasonal swelling are the usual causes. Tightening the hinges, sometimes with a longer screw into the framing at the top hinge, or moving the strike plate often solves it. Planing the door is the last resort, and the cut edge must then be sealed.
Does the door from the garage into the house have to close by itself?
Yes. The National Building Code, as reproduced in provincial codes, requires that door to have a self-closing device and to be tight-fitting and weatherstripped to keep gas and exhaust fumes out of the house. Your municipality can confirm what applies to your home.
What should I know before adding a pocket door?
The wall beside the opening must be free of wiring, plumbing and ducts across the full width of the door, and a load-bearing wall needs a properly sized header. Fitting one into an existing wall means opening the drywall, so it is easiest to plan during a renovation, with an electrician moving any switches or outlets.
Can I paint over a stained wood door?
Yes, once the finish is cleaned, lightly sanded and coated with a bonding primer. Skipping the primer is the usual reason paint peels off varnished doors.
Sources
Written by the LokalMatch editorial team. Reviewed by Zubair Afzal on September 10, 2026. How we write and check our guides