Replacing interior and entry doors: prehung vs slab, hardware, and what actually matters

Most people live with bad doors for years because doors feel like part of the house rather than a project. Hollow builder-grade slabs that boom like a drum, latches that never caught, a front door that leaks air you can feel from the couch. None of it is hard to fix, and almost none of it requires opening a wall.

The decisions that matter are fewer than the catalog suggests: prehung or slab, solid or hollow, and how much you care about the entry door. Get those three right and the rest is hardware.

01A quarter of Massachusetts doors were hung before 1940

Replacing an interior door sounds like a weekend errand until you meet the house. Across Massachusetts single-family homes, 24.5% predate 1940, and 6.4% were built before 1900. In those houses a door is rarely a standard slab in a standard opening. It is often original millwork hanging in a frame that has settled out of square over a century, sealed under layers of paint, and fitted with mortise hardware that no big-box hinge kit will match. In a quarter of the state's houses, replacing a door means negotiating with 1920s carpentry, not shopping for it.

The rest of the stock spans every era, and each one hangs doors differently. Public records put 18.1% of homes at 1900 to 1939, 21.2% at 1940 to 1959, 23.6% at 1960 to 1979, 19.7% at 1980 to 1999, and 11.0% at 2000 or later. A 1965 split-level usually takes a stock prehung door without drama. A 1910 Victorian usually does not. Knowing which side of that line your house sits on is the difference between a quick swap and a custom fit, and it should shape your budget before you shape any openings.

02Prehung vs slab: which interior door replacement is right for you

A slab is just the door. A prehung door arrives already hinged inside its own frame, and you install the whole assembly. If your existing frame is square, undamaged, and you are keeping the same size, a slab swap is cheaper and faster, but you have to mortise hinges and bore the latch to match exactly. That is fussy work with real consequences for how the door closes.

In older housing stock, and Massachusetts has plenty of it, frames are rarely square. A prehung unit lets you shim a straight frame into a crooked opening and hide the sins with casing. If your house predates the 1950s, assume prehung unless you have evidence otherwise. Upgrading from hollow-core to solid-core doors is the single biggest livability change: they block sound between bedrooms and simply feel like a better house.

03Upgrading an exterior or entry door

An entry door does three jobs: security, weather, and first impression. Steel and fiberglass units outperform most wood doors on the first two and cost less to maintain; a well-built wood door wins on the third and asks for refinishing in return. In a cold climate the weatherstripping and threshold matter more than the slab material, because a beautiful door with a daylight gap under it is just an expensive draft.

This is a moderate project rather than a light one, mostly because exterior openings hide surprises: rotted subsill, out-of-plumb framing, flashing that was never right. Budget your patience for the opening, not the door.

04Hardware and locksets: where cheap shows

Door hardware is touched every day, which is why cheap levers feel cheap forever. Match the function to the room: passage for closets and hallways, privacy for bedrooms and baths, keyed or smart locks for entries. Keep one finish family through the house rather than matching each door to its room. For entry doors, a quality deadbolt with a reinforced strike plate and long screws into the framing does more for security than any smart feature.

05Pocket, barn, and bifold doors for tight spaces

A swinging door claims a surprising amount of floor. Pocket doors give it all back but require opening the wall to install the frame, so they belong in projects where the wall is already open. Barn doors install on the wall surface, which is why they became popular, but they do not seal: sound, light, and smells pass freely, so keep them off bathrooms people actually use. Bifolds and sliding bypass doors remain the pragmatic answer for closets. Pick by how the room is used, not by what photographs well.

06Fire-rated doors: the one the inspector checks

The door between an attached garage and the house is a life-safety item, not a style choice. Code generally requires a fire-rated or solid wood door of minimum thickness there, self-closing hinges included in many jurisdictions. If you are replacing that door, replace it like for like or better. In Massachusetts this comes up at sale time, when smoke and carbon monoxide inspections put fresh eyes on the house, so it is cheaper to get right now than to scramble before a closing.

07What to weigh before you touch a door

Door projects are small in scope and large in surprises. The frame, not the door, decides how the job goes, so most of the thinking should happen before anything comes off its hinges.

Swapping a slab, installing hardware, and hanging a prehung interior door are all achievable DIY if you own a chisel, a level, and patience; the skill is in shimming, not strength. Entry doors are a step up because of flashing and weatherproofing, and a bad install rots the wall slowly and invisibly, so many people hand that one to an installer. Pocket doors mean opening the wall, and if there is wiring in that wall a licensed electrician must relocate it. No plumbing or gas licenses are in play here, which makes doors one of the friendlier categories to learn on.

08What it typically costs

Nationally, interior door costs swing on three things: the door itself, the condition of the opening, and the finish standard. A paint-grade hollow-core slab in a true frame sits at the bottom of every range, while solid-core, stain-grade, or custom-sized doors in settled frames climb quickly because the labor shifts from installing to fitting. Lead-safe practices on pre-1978 paint, hardware conversions, and matching existing casing profiles all add cost, while doing several doors in one visit usually brings the per-door price down.

Broad national planning ranges as of 2026, not quotes or offers. Local prices vary widely; get multiple written estimates for your own home.

09The short version

Start with a walk-through, not a catalog. Count your doors, note which bind or rattle, and date the hardware, because that inventory tells you whether you are shopping or restoring. A full door replacement is not inherently a good or bad project. If you are settling in for a decade, fitting quiet, solid doors to every opening is money you feel daily. If you are selling in a year, tuning what is there usually fits your plans better.