Interior doors — types, materials, and how to choose

Staff

05 Jun 2025 — 5 min read

This article is for educational purposes only and is not a substitute for professional advice. Local codes, regulations, and best practices vary by region.

Interior doors are the partition between rooms. They seem simple, but quality varies dramatically. A cheap door rattles, swings unevenly, and sounds hollow. A quality door closes quietly, swings smoothly, and dampens sound between rooms. Understanding the differences helps you choose doors that last and function well, which is especially important for rooms where privacy or sound control matters.

Hollow-Core Doors

A hollow-core door is mostly air with a cardboard honeycomb interior. It’s light, inexpensive, and adequate for closets and utility spaces. Hollow-core doors cost $30 to $100 depending on size and style. They’re durable enough for occasional use, but heavy daily use damages them. The door warps, the frame breaks, and the structure deteriorates.

Hollow-core doors transmit sound easily. A conversation in the next room is perfectly audible through a hollow-core door. They provide privacy visually but not acoustically.

Hollow-core doors are fine for bedrooms and bathrooms in apartments and modest homes where cost is a major factor. For primary bedrooms, offices, or any space where you want sound isolation, they’re not adequate.

Solid-Core Doors

A solid-core door has a solid wood or composite interior. It’s heavier and denser than hollow-core, which dampens sound and improves durability. Solid-core doors cost $100 to $300 depending on size and style. They last longer and function better than hollow-core doors.

Solid-core doors significantly reduce sound transmission. A conversation in the next room is muffled but not completely inaudible. They provide better privacy than hollow-core doors and swing with better balance.

Solid-core doors are appropriate for most interior applications. The cost difference between hollow-core and solid-core is $50 to $200 per door, which is reasonable for the improved quality and sound dampening.

Solid Wood Doors

A solid wood door is made from solid wood throughout. It’s beautiful, durable, and the most expensive option. Solid wood doors cost $200 to $800 or more depending on wood species and style. They’re built to last decades and become more beautiful with age and finish refinement.

Solid wood doors provide excellent sound dampening and durability. They don’t warp like solid-core doors might. They’re appropriate for high-traffic areas, primary bedrooms, and any space where you want the best quality.

Solid wood doors require maintenance to maintain their finish. They can scratch, dent, or stain, which either adds character or requires refinishing depending on your perspective.

Pre-Hung vs. Slab

A pre-hung door is a complete door assembly. It includes the door slab, the frame (jamb), hinges, and usually the hardware. Pre-hung doors simplify installation. You set the frame in the opening, level and shim it, and fasten it to the surrounding structure. Then you install trim around the frame. This is a straightforward installation.

A slab door is just the door panel without the frame. Slab doors are appropriate when you’re replacing a door in an existing opening where the frame is already installed and in good condition. You remove the old door, hang the slab on the existing hinges, and install new hardware.

Pre-hung doors cost more than slabs (you’re buying the frame) but simplify installation. Slabs are cheaper but require an existing opening and frame.

Bifold and Pocket Doors

Bifold doors fold open to the side, useful for closets where you don’t want a door swinging into the room. They’re space-efficient. Bifold doors cost $100 to $400 depending on size and quality.

Pocket doors slide into the wall cavity, completely disappearing when open. They’re elegant and space-efficient. Pocket doors cost $200 to $600 and require more complex installation because they need a pocket frame built into the wall.

Both bifold and pocket doors work well for closets, laundries, and pantries where a swinging door wastes space.

Materials and Finishes

Interior doors come in various styles. A flat-panel door is contemporary and simple. A raised-panel door is traditional. A glass-panel door provides light between rooms. A louvered door provides ventilation (useful in laundries and basements).

Doors are available primed (ready to paint) or stained (ready to varnish). Most builders use primed doors for simplicity. You can paint them any color you want. Stained doors are more expensive but finished beautifully if you want wood tones.

Acoustic and Privacy

Sound transmission class (STC) measures how well a door blocks sound. A hollow-core door has an STC of about 18 to 20. A solid-core door has an STC of about 30 to 35. A solid wood door might achieve 35 to 40. Higher numbers mean better sound dampening.

The difference is perceptible. An STC of 20 versus 30 is a significant improvement in acoustic privacy. For bedrooms and bathrooms, a solid-core or solid wood door is worth the investment.

Gasket seals installed around the door frame improve sound isolation by preventing sound leakage around the edges. They’re useful in offices and primary bedrooms.

Installation

Pre-hung door installation involves setting the frame in the opening, leveling it with shims, and fastening the frame to the surrounding structure. Then you install trim around the frame to finish the edges. Most competent homeowners can install a pre-hung door successfully.

Slab door installation is simpler if the existing frame is good. You hang the new slab on the existing hinges and install hardware. This is straightforward DIY work.

Pocket door installation is more complex. The pocket frame must be built into the wall cavity before drywall is installed. If you’re adding a pocket door after the wall is finished, it’s a larger project that might benefit from professional installation.

Hardware

Door hardware includes hinges, handles, and locks. Quality matters. Cheap hinges wear out quickly, and doors sag. Quality hinges from reputable manufacturers last decades.

For interior doors, you need hinges, a handle or knob, and potentially a lock. For bedrooms and bathrooms, a keyed lock or button-lock provides privacy. For utility spaces, a simple handle is sufficient.

Finish matters for aesthetics and durability. Chrome finishes are sleek and modern. Brass or bronze finishes are traditional. Brushed nickel is versatile. Finishes should match throughout your home for cohesive appearance.

Maintenance

Quality interior doors require minimal maintenance. Keep hinges clean and occasionally lubricate them if they squeak. Check that handles are tight and tighten screws if they loosen. Replace weatherstripping around the frame if it wears out and air leaks in.

Doors can develop minor scratches, dents, or stains. Solid wood doors can be refinished. Painted doors can be touched up with matching paint. Solid-core and hollow-core doors that are damaged are usually replaced.

Cost and Value

Interior doors are one of the visible details of your home. Quality doors look good, function smoothly, last longer, and provide better acoustic privacy. The incremental cost of upgrading from hollow-core to solid-core is $50 to $150 per door. For a home with 10 interior doors, that’s $500 to $1500 total for significantly better quality and longevity.

For primary bedrooms, offices, and bathrooms where you spend significant time, solid-core or solid wood doors are worth the investment. For closets and utility spaces, hollow-core is adequate.

The Reality

Interior doors are easy to overlook, but they’re part of your daily experience. A door that swings smoothly, closes quietly, and looks good affects how you feel about your home. A door that sticks, squeaks, and looks cheap is frustrating.

Invest in solid-core or solid wood doors for spaces where you want quality, privacy, and durability. Use hollow-core doors for closets and utility spaces where cost matters more than quality. You’ll end up with doors that work well and look good.