Doors · Service

Interior door installation, by the houseful

One hollow-core door is a Saturday. Ten of them, matched, with new casing and consistent hardware, is a two-day job with a skip outside — and that is the version worth hiring for.

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In short

What is interior door installation?

Interior door installation means fitting the doors between rooms — bedroom, bathroom, closet, hallway. The choice is between a slab, which is just the door hung in the frame you already have, and a pre-hung unit, which replaces the frame too. A single slab in a sound frame is genuinely a DIY afternoon. The job most people hire for is the other one: replacing every door in the house at once, with matched styles, matched hardware and new casing.

Triggers

Signs you need interior door installation

The doors are hollow-core flush panels from an earlier decade and every one of them looks it
You can hear normal conversation clearly through a closed bedroom or bathroom door
Several doors have been planed, packed or rehung over the years and none of them latch the same way
The frames are sound but the doors are damaged — dents, holes, delaminated skins — which is the classic slab-replacement case
Openings in an older house are non-standard sizes and every off-the-shelf door needs trimming

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The job

How interior door installation actually works

Counting, measuring and sizing every opening

On a whole-house job the installer measures each opening for width, height and jamb depth, records the handing and swing, and flags which are standard sizes and which need a custom or trimmed door. Pre-1960s houses routinely have several that are not standard anything.

Watch for: A price quoted per door before the openings have been counted. Two or three non-standard openings change the material bill and the lead time significantly.
Deciding slab or pre-hung, opening by opening

This is not one decision for the house. Where the frame is plumb, square and undamaged, a slab is faster, cheaper and leaves the casing alone. Where the frame is racked, out of alignment, or the wrong depth for the wall, a pre-hung unit is the honest answer.

Watch for: A blanket recommendation either way. All-pre-hung inflates the bill and tears off casing that did not need to come off; all-slab hangs new doors on frames that were the problem.
Core choice — where solid-core actually earns its money

Hollow-core is light, cheap and fine for closets. Solid-core is substantially heavier, deadens sound noticeably, and is the single upgrade most homeowners say they can feel. Solid wood is heavier still and moves with humidity.

Watch for: Solid-core doors hung on the existing lightweight hinges. The extra weight needs three hinges and screws into the framing, not two hinges and a hopeful jamb.
Hanging, shimming and the self-swinging door

Each door is shimmed plumb behind the hinges and at the strike, and the reveal is set even down both sides and across the top. Shimming behind the hinges is what stops a door drifting open or shut on its own.

Watch for: Doors that swing themselves closed after the crew has left. That is a plumb error, and it is much cheaper to correct before the casing is nailed on.
Casing, hardware and finishing

Casing is fitted or reused, hardware is set at a consistent height throughout the house, and every door is cycled and adjusted. On a whole-house job the value is in the consistency — the same lever, the same height, the same reveal on every opening.

Watch for: Mixed handle heights and mismatched hinge finishes across the house. Individually invisible, collectively the thing that makes the job look amateur.

Money

What does interior door installation cost?

Interior doors are the cheapest doors in the house — a hollow-core slab is inexpensive and a pre-hung unit modest. The number that matters on a whole-house job is per opening installed, commonly $150 to $600, with solid-core, custom sizes and new casing pushing toward the upper end.

See the full interior door installation cost guide — by material, size and region →

Straight answer

When interior door installation is the wrong call

Everyone else ranking for this is paid when you say yes. Here's when you shouldn't.

It is one door and the frame is fine. A single slab, hung on existing hinge mortises, is a legitimate DIY afternoon. Hiring for it means paying a trip charge that exceeds the door.
The door only sticks in summer. Seasonal swelling is normal in wood doors. Easing the one binding edge costs nothing; replacing the door does not stop it happening to the next one.
You want soundproofing rather than sound reduction. A solid-core door helps, but sound also travels through the gap under it, through the walls and through shared ductwork. If the goal is a genuinely quiet room, the door is one part of a larger job.
You are widening an opening for wheelchair access. Clear width, hardware reach and threshold requirements are handled properly by Aging in Place. Do not start from a door catalogue.
The flooring is going in later. New flooring changes the undercut every door needs. Hang the doors after the floor, or budget for a second visit to trim them all.
Only the hardware is dated. Swapping knobs for levers across a house is a fraction of the price and changes how the place feels more than most people expect.

Your options

Types of interior door installation

Pre-hung vs slab

The decision, opening by opening.

Wood doors

Solid wood behaviour, movement and finish.

Compare doors options side by side →

Straight answer

Can I do this myself?

Reasonable to DIY

Replacing a single slab in a sound frame, reusing the existing hinge positions
Swapping handles, latches and hinges
Trimming a hollow-core door's bottom by a modest amount to clear new flooring — staying inside the solid rail at the base
Removing and refitting casing carefully where it is being reused

Call a licensed pro

Pre-hung units, where the frame has to be shimmed plumb in an opening that may not be
Solid-core and solid-wood doors, which are heavy enough that hanging them alone goes wrong quickly
Non-standard openings in older homes, where the door has to be scribed or ordered custom
Whole-house projects, where the value is in consistency and speed rather than in any single door

Before you sign

What to check when hiring for interior door installation

Which openings are you quoting as slab and which as pre-hung, and why each?

A per-opening answer means someone looked at the frames. A single blanket answer means they did not.
How many of my openings are non-standard sizes?

Older houses usually have several. Custom or trimmed doors affect both price and lead time, and it is much better to know before the order goes in.
Is casing being reused or replaced, and who paints it?

The largest hidden variable on a whole-house door job. Reused casing means careful removal; new casing means filling, caulking and painting.
Are you fitting three hinges on the solid-core doors, with screws into the framing?

Solid-core doors are heavy. Two lightweight hinges into a jamb alone will sag inside a year.
What is the undercut, and is the flooring going in before or after?

Doors hung before new flooring frequently all have to come off again. Sequencing this correctly saves a whole return visit.
How many doors a day, and how much of the house is unusable while you work?

Whole-house door jobs are dusty and every room is briefly open. Worth knowing the plan if anyone is at home during the day.

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Local pros

Interior Door Installation near you

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Related work

Often done at the same time

Door Repair

Sticking, sagging and latch problems

French Door Installation

Interior pairs between rooms

Entry Door Replacement

The exterior side of the same project

All doors services →

Go deeper

Guides & terms

Guides

Pre-hung vs slab, explained

All doors guides →

Terms on this page

Pre-hung door

Full doors glossary →

FAQ

Interior Door Installation — questions people ask

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Should I buy slab or pre-hung interior doors?

Judge it frame by frame. If the existing jamb is plumb, square, undamaged and the right depth for the wall, a slab is cheaper, faster and leaves your casing untouched — you reuse the hinge mortises and cut the latch. If the frame is racked, has been shimmed repeatedly, is rotting at the base, or you want a different width, a pre-hung unit replaces the frame and jamb as one. Most whole-house projects end up a mix of both.

Is a solid-core door worth the extra money?

For bedrooms, bathrooms, home offices and anywhere adjoining a noisy room, most people say yes and describe the difference as the upgrade they notice daily. Solid-core doors are markedly heavier and deaden conversation and television noise in a way hollow-core doors do not. For closets and pantries the extra weight and cost buy nothing. A sensible compromise on a whole-house job is solid-core on the rooms people sleep and work in, hollow-core everywhere else.

Can I replace interior doors without replacing the frames?

Yes — that is exactly what a slab replacement is, and it is the most common way to modernise a house full of dated doors without disturbing a single piece of trim. The conditions are that the frames are sound and square and that you can either reuse the existing hinge mortises or cut fresh ones cleanly. Check each frame with a level and by measuring the diagonals before assuming it applies to the whole house.

How long does it take to replace all the doors in a house?

For a typical house of eight to fifteen openings, a competent crew is usually looking at one to three days — faster where most are slab replacements into sound frames, slower where pre-hung units, new casing and painting are involved. Custom sizes for non-standard openings add lead time before work starts rather than time on site.