Door materials

The material a door is made from affects everything downstream: how it performs against weather and sound, how it's finished, how it's cut and trimmed during installation, and how long it lasts. This section covers the five main material categories used in residential doors.

Hollow-core

Hollow-core doors have a thin skin — usually wood veneer or hardboard — stretched over a lightweight frame surrounding a cardboard honeycomb core. They are the most common interior door in residential construction, and for good reason: they're inexpensive, light enough to hang easily, and adequate for low-traffic spaces.

What they don't do well is block sound or absorb impact. Knock on one and you'll immediately understand the limitation. They also can't be trimmed as aggressively as solid doors — trim too much and you cut into the hollow cavity, which requires repair before the door is usable.

Best for: Bedrooms, closets, hallways — anywhere cost and weight matter more than acoustics or durability.

Solid-core

Solid-core doors use the same exterior skin as hollow-core but fill the interior with a composite wood block or particleboard core. The result is a door that feels and performs substantially better: quieter, more impact-resistant, and more stable over time.

They're heavier than hollow-core doors, which means hinges and framing need to be up to the task, but they hang and trim the same way. They accept paint and stain well and are a straightforward upgrade over hollow-core in any application where sound or durability is a priority.

Best for: Home offices, laundry rooms, bathrooms on shared walls, or any interior space where hollow-core falls short.

Solid wood

Solid wood doors are milled from timber throughout — no composite fill, no honeycomb. They're the traditional choice for exterior doors and high-end interior applications, and they offer genuine aesthetic depth that veneered doors can't replicate.

The tradeoff is sensitivity to moisture. Wood expands and contracts with humidity, which means a solid wood door that fits perfectly in summer may stick in winter, or gap in a dry climate. This isn't a dealbreaker, but it does require proper finishing on all six faces (including top and bottom edges) and occasional maintenance. An unfinished or poorly finished wood door will move — it's not a question of if, but when.

Solid wood doors can be trimmed, planed, and shaped more freely than any other type, which makes them forgiving during installation and adjustment.

Best for: Exterior doors, front entries, and interior applications where appearance justifies the maintenance commitment.

Fiberglass

Fiberglass doors are foam-filled composite units designed to replicate the look of wood without its moisture sensitivity. They don't warp, swell, or rot, and they outperform wood on insulation — a foam-core fiberglass door will have a significantly higher R-value than a solid wood equivalent of the same thickness.

High-quality fiberglass doors can be stained to a convincing wood grain finish. Lower-quality units look like what they are. They can be painted without issue.

The main limitation is that fiberglass can't be field-trimmed the way wood can. If the rough opening is significantly out of square or undersized, a fiberglass door is less forgiving than wood or solid-core.

Best for: Exterior doors where insulation, durability, and low maintenance are priorities.

Steel

Steel doors are the most secure and most thermally stable option for exterior applications. They're foam-filled like fiberglass, dimensionally consistent, and resistant to warping. They also tend to be the most affordable exterior door option.

The weaknesses are cosmetic and practical: steel dents, and dents are difficult to repair cleanly. Steel doors also conduct cold at the edges if the thermal break between interior and exterior faces is inadequate — look for doors with a polyurethane foam core and a proper thermal break in the frame.

Steel doors are almost always painted. Staining is not an option.

Best for: Side entries, garage entries, and any exterior opening where security and cost matter more than appearance.

Comparison at a glance

Material	Interior / Exterior	Trimmable	Sound control	Moisture resistance	Relative cost
Hollow-core	Interior only	Limited	Poor	Poor	$
Solid-core	Interior only	Yes	Good	Fair	$$
Solid wood	Both	Yes	Good	Fair (with maintenance)	$$–$$$
Fiberglass	Exterior	Limited	Good	Excellent	$$$
Steel	Exterior	No	Fair	Excellent	$$

Next: Styles & configurations

Material determines how a door performs. Styles & configurations covers how it operates and what it looks like.