Interior doors provide privacy, reduce noise transmission, and contribute to the overall design of your living spaces. Whether you’re building or renovating a home, understanding the various types, materials, and styles can help you pick the best doors for your project. This guide will explore everything you need to know about interior doors, from construction methods to installation tips.
Types of Interior Doors
Interior doors come in several types, each with unique characteristics and benefits. Let’s explore the most common options for homeowners.
Solid Core Doors
Solid core doors (#1) are durable insulators. They typically consist of a wood or medium-density fiberboard (MDF) frame filled with a solid core material made of particleboard, wood fiber, or other composite materials.
Molded MDF skins cover the front and back of the glued-together frame, creating a smooth surface. The solid core provides sound absorption and density, making these doors ideal for areas where privacy and noise reduction are important, like your bedrooms or home office.
In a recent Ask This Old House visit, homeowner Henrik told general contractor Nathan Gilbert that he wanted to swap out his hollow-core doors for solid-core ones for two reasons: “One, just the feel of it, have something that feels a bit more solid. And the second one is really around sound insulation.” With a home office, bathroom, and his daughter’s bedroom all off the same hallway, the upgrade was a practical priority.
Hollow Core Doors
Hollow core doors (#1) are a lightweight and affordable option. Similar to solid core doors, hollow core doors have a frame covered by MDF or wood veneer skins. However, the interior is either empty or filled with a cardboard honeycomb structure to prevent flexing, so they aren’t as useful for sound reduction. Still, they are easier to handle and install. They’re most suitable for closets, pantries, or areas where sound insulation is less critical.
From the Jobsite: TOH general contractor Tom Silva has seen firsthand what’s inside a hollow core door: “This veneer is actually all you have between each side of the door, except for some strips of cardboard or some other filler to hold the veneers together. And yeah, they are pretty tinny.” For homeowners looking to upgrade, the difference in feel and sound insulation compared to a solid core door is immediately noticeable.
Solid Stile and Rail Doors
Solid stile and rail doors (#2) offer a traditional look and superior strength. These doors are made with vertical stiles and horizontal rails made of engineered or solid wood, occasionally MDF. The components are held together with glue and dowels, creating a sturdy frame.
Panels, usually made of MDF, fit within this frame and often feature better milled details than molded doors. The door’s face can be finished with wood veneer or a smooth layer of MDF. While more expensive than others, these doors have a classic appearance and long lifespan.
Joinery Matters: How the frame is joined is a critical consideration. Traditional mortise-and-tenon joinery — where a tongue of wood (the tenon) fits into a matching slot (the mortise) — provides maximum strength and durability. As the craftsmen at Hahn’s Woodworking Company demonstrate, mortise-and-tenon joinery is the most common method used on custom doors because of its superior strength. Some manufacturers further reinforce the joint between the rails and stiles by drilling a hole and inserting a glued dowel after assembly.
Materials Used in Interior Door Construction
Here are the most common materials used in interior door construction:
MDF (Medium-Density Fiberboard)
MDF is popular due to its affordability and versatility. It’s made from wood fibers compressed with resin, which makes a smooth, uniform surface ideal for painting. MDF is also resistant to warping and shrinking.
Carved MDF doors (#3) offer an inexpensive way to achieve the look of traditional raised panel doors. Two solid slabs of MDF are glued together, and the faces are detailed with a router bit. This method creates the appearance of separate panels, rails, and stiles in one piece, reducing costs compared to solid wood versions with applied molding.
Pro Insight: This Old House master carpenter Norm Abram has long championed MDF for painted work: “With plywood, every time you expose an edge, you’ve got to find a way to cover it, but with MDF the edge is treated just like a solid piece of wood.” He also notes that MDF’s nondirectional composition means less waste: “With plywood, you have to follow the grain, so you wind up with lots of small pieces of scrap you can’t really use. Whereas with MDF, it’s nondirectional, so you get more efficient use of the sheet.”
Engineered Wood
Engineered wood comprises multiple layers of bonded wood veneers or fibers, combining the benefits of solid wood and manufactured materials. It is also less prone to warping or cracking than solid wood, making it a good choice for areas with fluctuating humidity levels.
On a recent This Old House TV project, Tommy Silva explained why MDF-core interior doors have become a go-to choice. As he showed Kevin O’Connor, “The styles, rails, and panels are made of MDF, medium density fiber wood. But around the outside edge of the door, there’s a piece of poplar right here, that you can screw your hinges in. The screws that hold the hardware will get a good bite.” Kevin noted the stability advantage, and Tommy confirmed: “It’s very stable, and it paints up really well.”
Solid Wood
Solid wood doors are timeless and resistant to wear and tear. They can be made from various wood species with unique grain patterns and characteristics. While more expensive than other options, solid wood doors provide excellent sound insulation and can last decades with proper care. It’s often used in high-end stile and rail doors, showcasing the natural beauty of the wood grain. These doors can be stained or painted to match your home’s decor.
Old-House Hallmark: As TOH Magazine notes, one of the easiest ways to tell a new house from an old one is by its interior doors. Doors in homes built before 1950 are typically made of solid wood—whether oak, maple, chestnut, or mahogany. They’ve got heft, and they make a satisfying thump when you knock. They also have sturdy stiles and rails that frame handsome panels in a variety of configurations, depending on the home’s architectural style.
Interior Door Styles and Designs
Interior doors come in many styles to suit different architectural designs and personal preferences. Here are some popular options:
Panel Doors
Panel doors feature raised or lowered panels surrounded by stiles and rails. They can have anywhere from one to eight panels, with six-panel doors being a classic choice. Panel doors add visual interest and depth to a room, making them popular for traditional and contemporary homes.
Flush Doors
Flush doors have a smooth, flat surface on both sides, giving them a modern look and making them easy to maintain. Flush doors can be made from various materials, including MDF, plywood, or hardboard, and are often used in contemporary or minimalist interiors.
French Doors
French doors consist of multiple glass panes set within a frame. They allow light to flow between rooms while still providing separation. French doors are often used for entryways to large family rooms or outdoor spaces, adding elegance to your home’s design.
A Rich History: When the French crossed doors with windows back in the 1600s, they had light and airflow in mind. As TOH contributor Jill Connors writes, “Exported to North America a century later, pairs of the multipaned doors could be flung open to catch a breeze in summer while inviting in the sun year-round.” Thomas Jefferson himself installed several pairs at Monticello. In 18th-century French Colonial communities along the Gulf Coast, these windowed doors hung in the exterior walls of virtually every room of Creole cottages and plantation houses, maximizing ventilation in the region’s hot and humid climate.
Barn Doors
Barn doors have gained popularity recently for their rustic charm and space-saving design. These doors slide along a track mounted above the doorway, making them ideal for areas where swing space is limited. Barn doors can be made from various materials, including wood, metal, or glass.
Real-World Solution: TOH readers Ashli and Lee Malinek of British Columbia turned to a barn door when a swinging door between their kitchen and mudroom kept hitting the table in their eating area. “This idea came out of necessity,” Ashli says. “I love the look of sliding barn doors and realized that was the solution.” Lee built the door from pine 2x4s and slats, welded the track and straps from quarter-inch steel, and sourced wheels from an automotive shop—proving that barn doors can be a creative DIY project with off-the-shelf components.
Reader Favorite: When TOH Magazine asked fans about sliding barn doors, more than 1,000 readers wrote in wanting to know the best way to tackle this project. The appeal is clear: hanging a door on a track means you don’t have to rip open and reframe a wall for a pocket door, and mounting hardware is available in all manner of styles and budgets.
Choosing the Right Interior Door
Keep these factors in mind when picking the perfect door for your home:
Considering Room Function
Bedrooms and bathrooms may benefit from solid core doors for increased privacy and sound insulation. Lighter hollow-core doors are better for closets and pantries.
Matching Your Home’s Decor
Your interior doors should complement your home’s overall style. Traditional homes could benefit from panel or French doors, while modern interiors are better suited to flush or barn doors. When making your choice, consider the existing trim, flooring, and furniture.
Budget Considerations
Interior door prices vary widely depending on the material, style, and quality. Set a realistic budget for your project, keeping in mind that investing in higher-quality doors can pay off in terms of lifespan and looks in the long run.
Interior Door Installation and Maintenance
Properly install and maintain your interior doors to make them last longer.
Interior Door Installation Tips
If you’re handy and have some DIY experience, consider hanging interior doors yourself to save some money. Make sure you have the right tools and carefully follow installation instructions. Pay special attention to leveling and properly securing the door frame.
Hire a professional to hang and align your doors properly for complex installations or if you’re not confident in your DIY skills.
Expert Insight: TOH carpenter Nathan Gilbert notes: “In a best-case scenario, framing an opening and hanging a door is within the ability of an experienced do-it-yourselfer, especially when using a previously framed opening.” However, he recommends “having an experienced carpenter on call in case you encounter any surprises such as wires, pipes, or structural damage, like rot” — advice worth heeding before you cut into any wall.
Proper Interior Door Care and Maintenance
Regular maintenance can extend the life of your interior doors. Clean them with a soft, damp cloth and mild soap, and avoid using harsh chemicals that could damage the finish. Lubricate hinges and hardware as needed and address any issues immediately to prevent further damage.
Interior Door Sizes and Standards
Choose the right door size for your home to avoid expensive custom orders.
Common Interior Door Dimensions
Most interior doors come in standard widths of 24, 28, 30, 32, and 36 inches. The most common height is 80 inches, although taller options are available. The standard thickness for interior doors is typically 1⅜ inches.
Custom Sizing Options
You might need custom-sized doors if you have an older home or unique architectural features. Many manufacturers offer made-to-order doors to fit non-standard openings, though these will cost more than standard sizes.
Cost Factors for Interior Doors
The cost of interior doors can vary significantly based on several factors:
Material Costs
Material choice significantly impacts door cost. Hollow core doors are typically the most affordable, while solid wood doors are often the most expensive. MDF and engineered wood options usually fall in the middle range.
| Material Type | Cost Range |
| Hollow core | $30 – $400 |
| Solid core | $70 – $500 |
| Solid wood | $160 – $590 |
| MDF | $400 – $620 |
Interior Door Installation Costs
Professional installation costs can vary depending on your location and the job’s complexity. Simple replacements will cost less than installing new door frames or modifying existing openings.
Additional Features and Upgrades
Features like decorative glass inserts, high-end hardware, or custom finishes can increase the overall cost of your interior doors. Consider which upgrades are most important to you and budget accordingly.
Our Conclusion
Whether you prefer classic solid wood panel doors or more modern flush MDF doors, consider factors like room function, overall style, and long-term care to pick the best interior doors for your needs. With proper installation and maintenance, your interior doors will last for years.
