Door Slab vs Prehung: Which is Right for Your Project?

Starting a door project? Awesome! Whether you’re replacing an old interior door, upgrading your front entryway, or doing a full renovation, one of the first choices you’ll face is: Should I buy a door slab or a prehung door?

It might sound like technical jargon, but understanding the difference is super important! Choosing correctly impacts:

• Installation time and difficulty: One is way easier to install than the other!
• Total project cost: The door price is only part of the story.
• The final look and function: Getting it right means a door that swings smoothly and seals properly.

Making the wrong choice can lead to frustration, extra costs, or a door that just doesn’t work right. Yikes!

This guide is here to help everyone – homeowners tackling a weekend project, DIY enthusiasts, and even contractors looking for a quick refresher. We’ll clearly explain:

• What exactly a door slab and a prehung door are.
• The key differences in cost, installation, and customization.
• When each option makes the most sense.
• Tips for measuring and avoiding common mistakes.

By the end of this guide, you’ll be able to choose between a door slab and a prehung unit with confidence! Let’s dive in.

Understanding Door Terminology: Slab Talk vs. Prehung Package

First, let’s get the names straight. Getting these basic definitions clear is the first step in making the right choice.

What is a Door Slab? [Just the Door!]

A door slab is simply the door itself – that rectangular piece of wood, fiberglass, or steel that swings or slides. That’s it! No frame, no hinges attached to a frame, no hardware holes pre-drilled (usually).

• Components: Just the door panel.
• Types: Can be solid core (heavy, better soundproofing) or hollow core (lighter, cheaper). Learn the difference: Solid Core vs Hollow Core Doors. Styles can be flush (smooth flat surface) or panel (with decorative raised or recessed panels). See Flush Door vs. Panel Door.
• Prep: Usually comes “blank.” You (or your installer) need to cut recesses (mortises) for hinges and drill holes for the doorknob and latch mechanism. Some slabs might come pre-drilled for hardware, but not attached to a frame.

What is a Prehung Door? [The Whole Kit!]

A prehung door is a complete, ready-to-install door system. It includes:

• The door slab itself.
• The frame (jambs – the two sides and the top piece) that the door will sit in.
• Hinges already attached to both the door slab and the frame jamb, perfectly aligned.
• Often pre-drilled holes for the doorknob and latch.
• Sometimes includes the door stop molding already attached to the frame.
• Exterior prehung doors also include the threshold (sill) and weatherstripping.

Think of it as a door “kit.” You install the entire unit into the rough opening in your wall. Need more detail? Check out what is a prehung door?. Knowing the parts of a door system helps visualize this.

Self-reflection: Is the basic difference still a bit unclear? Sometimes a really simple explanation helps. If you’re looking for just the basics explained clearly for homeowners, check out our quick overview: What is a Prehung Door vs Slab? Simple Explanation for Homeowners.

Key Differences at a Glance: Slab vs. Prehung

Feature	Door Slab	Prehung Door
What’s Included	Door panel ONLY	Door panel + Frame + Hinges
Prep Needed	Mortise hinges, drill hardware holes	Minimal (mostly shimming frame)
Installation	More complex, requires precision	Easier, faster
Best For	Replacing door in existing good frame	New walls, replacing damaged frame
Cost (Unit)	Lower	Higher
Cost (Total)	Can be higher if hiring pro install	Can be lower total cost (faster install)
Hardware	Choose/buy separately	Hinges included; choose handles/locks

Comprehensive Comparison: Digging Deeper

Let’s compare these two options across key areas:

Installation Complexity: DIY Dream or Pro Project?

• Slab Door Installation:
  • Process: Requires careful measuring, precise chiseling/routing for hinge mortises (on both door and frame), drilling accurate holes for hardware, ensuring perfect alignment within the existing frame.
  • DIY Difficulty: Difficult. Requires good carpentry skills, patience, and specialized tools (like hinge jigs, sharp chisels). Mistakes are easy to make (misaligned hinges = sticking door!).
  • Tools: Chisels, hammer, drill, hinge template/jig, tape measure, level, square.
  • Time: Can take several hours per door for an experienced DIYer, much longer for a beginner.
• Prehung Door Installation:
  • Process: Place the entire unit into the rough opening. Use shims (small wedges) to make the frame perfectly plumb (vertical) and level (horizontal). Secure the frame to the wall studs with nails or screws. Install trim (casing).
  • DIY Difficulty: Moderate. Much easier than a slab install! Still requires careful leveling and shimming, but avoids the tricky hinge/hardware prep.
  • Tools: Level (long one is best!), shims, hammer or nail gun/drill, tape measure, utility knife (for scoring shims).
  • Time: Can often be installed in 1-2 hours by someone with basic skills once the rough opening is ready.

Winner for Ease of Installation: Prehung Doors (by a long shot!)

Cost Analysis: Upfront vs. Total

• Unit Price: A door slab is always cheaper to buy off the shelf than a comparable prehung unit because you’re getting less material (no frame/hinges).
  • Slab Range (Interior): $50 (hollow) – $500+ (solid wood)
  • Prehung Range (Interior): $100 (hollow) – $800+ (solid wood)
  • (Exterior doors follow similar pattern, but starting costs are higher)
• Total Project Cost: This is where it gets interesting!
  • DIY: If you install yourself, a slab is cheaper overall (lower material cost). BUT, factor in tool purchase/rental if needed.
  • Pro Install: Hiring a professional to install a slab door often costs more in labor ($150-$400+ labor per door) than installing a prehung door ($100-$300 labor per door) because it takes much longer and requires more skill.
  • Result: For pro installs, a prehung door can sometimes be cheaper overall when you factor in the reduced labor cost, despite the higher unit price.
• Hidden Costs: Replacing a slab might reveal the existing frame is damaged/warped, forcing you to replace the frame anyway (pushing you towards prehung cost). Prehung needs trim (casing) installed around it ($$).

See our general Door Cost Guide for more pricing context.

Winner for Lowest Unit Cost: Door Slab
Winner for Potentially Lower Total Cost (with Pro Install): Prehung Door

Customization Options: Flexibility Factor

• Slab Doors:
  • Pros: More flexible if you have a non-standard sized existing frame you want to keep. Great for matching unique styles in older homes. You have complete freedom to choose hinge type/finish and exact hardware placement. Perfect for using salvaged or unique vintage doors.
  • Cons: Limited by the condition and size of your existing frame.
• Prehung Doors:
  • Pros: Ensures a perfectly matched, square frame specifically designed for that door. Often available in standard average door dimensions making planning easier. Exterior prehung units come with integrated weather seals and thresholds for optimal performance.
  • Cons: Less flexible for odd-sized openings (custom prehung units cost more). Limited to the hinge finishes offered by the manufacturer (usually standard options).

Winner for Flexibility (in existing frames/custom doors): Door Slab
Winner for Guaranteed Fit & Integrated System: Prehung Door

Performance Factors: How They Hold Up

• Weather Resistance (Exterior): Prehung exterior doors almost always win. They are designed as a system with integrated weatherstripping, interlocking thresholds, and tight-fitting frames to keep drafts and water out. Trying to weatherseal a slab door into an old frame perfectly is much harder. Getting this right is crucial, as explored in our guide comparing Prehung Exterior Door vs Slab: Pros, Cons, and Installation Tips.
• Energy Efficiency: Tied closely to weather resistance. A well-sealed prehung exterior unit is generally more energy efficient.
• Soundproofing: Depends mostly on the door slab’s core (solid core blocks more sound than hollow core) rather than slab vs. prehung itself. A well-sealed prehung frame helps slightly too.
• Security: A prehung unit can be more secure IF the frame is properly installed with long screws into the wall studs. Installing a slab into a weak existing frame offers less security. Security also heavily depends on the lockset chosen and frame reinforcement.
• Durability: Depends on the material of the door and frame, and the quality of installation. A poorly installed prehung door can fail just like a poorly installed slab.

Winner for Performance (Especially Exterior): Prehung Door

Door Material Considerations: Does it Change the Choice?

The door material influences weight, cost, and installation nuances, but the core slab vs. prehung decision often remains the same.

• Wood: Heavy (especially solid core). Requires precise hinge mortising for slabs. Prehung wood doors are heavy to lift into place. Needs careful sealing if exterior.
• Fiberglass: Lighter than solid wood but heavier than hollow core. Can be installed as slab or prehung. Prehung fiberglass is popular for exterior durability and efficiency.
• Steel: Relatively light (foam core) but strong. Usually sold prehung for exterior use due to integrated frame/seals. Slabs available but less common for DIY residential. (Compare with aluminum garage doors: Aluminum vs. Steel Garage Doors).
• Glass Inserts / French Doors: Adds significant weight! Prehung is strongly recommended for heavy glass doors (what are french doors?) to ensure hinges/frame are properly matched and aligned. See French Door Sizes for typical configurations.
• Composite Doors: Varies widely. Some (what is a composite door?) are similar to solid core wood, others are unique materials like wood-plastic composites or UPVC (what is upvc door?). Prehung often preferred for guaranteed system performance.
• Aluminum: Lightweight. Often used in patio sliders or storm doors, usually sold as complete units (effectively prehung). Learn what is a aluminum door?. (Compare with PVC: Aluminum vs PVC Doors).

Key Point: Heavier doors (Solid Wood, Glass Inserts, Steel) benefit more from the guaranteed alignment and matched hinges of a prehung unit.

When to Choose a Door Slab: Keeping the Frame Intact

A door slab makes sense when:

1. Your Existing Door Frame is in Perfect Condition: It’s square, plumb, level, and has no damage or rot. You only need to replace the door panel itself.
2. Matching Existing Style: You need to match a specific style or size in an older home where standard prehung units might not fit or look right.
3. Budget Interior Project (DIY): If you have the skills and tools (or are willing to learn/rent), installing an interior slab yourself is the cheapest way to replace a door panel. Determining Prehung Interior Doors vs Slab: Which is Better for Your Home? often comes down to frame condition and DIY ability in this scenario.
4. Using a Unique/Salvaged Door: If you found a cool vintage door slab, you’ll need to install it as a slab into an appropriate frame (either existing or newly built).
5. Need Custom Size Slab: Sometimes ordering just a custom-sized slab is easier/cheaper than a full custom prehung unit if the frame is good. Explore options for custom doors from us.

Measuring for a Slab Door:

• Measure the width, height, and thickness of your existing door slab precisely.
• Measure hinge locations: Distance from top of door to top of each hinge.
• Measure backset for hardware: Distance from door edge to center of doorknob hole.
• Goal: Order a new slab with the exact same dimensions and ideally matching hinge/hardware prep if possible (though doing prep yourself offers flexibility).

Common Slab Mistakes: Incorrect measurements; poorly cut hinge mortises (too deep/shallow/crooked); misaligned hardware holes; damaging existing frame during install.

When to Choose a Prehung Door: The All-in-One Solution

A prehung door is usually the better choice when:

1. New Construction: You’re framing new walls – installing a prehung unit into the rough opening is standard practice.
2. Replacing a Damaged Frame: If the existing door frame is rotten, warped, split, or otherwise damaged, you need to replace it anyway – a prehung unit includes the new frame.
3. Exterior Door Installation: Crucial for weatherproofing! The integrated frame, threshold, and weatherstripping provide a much better seal against drafts and leaks than trying to seal a slab into an old frame. This is a key factor discussed in Prehung Exterior Door vs Slab: Pros, Cons, and Installation Tips.
4. Saving Installation Time/Labor: Even if the existing frame is okay, the speed and ease of installing a prehung unit often makes it worthwhile, especially if hiring a pro or doing multiple doors.
5. Ensuring Proper Operation: Guarantees the door is properly hinged and aligned within its own frame from the factory. Less chance of sticking/binding issues if installed correctly.
6. Major Renovations: If you’re already tearing out walls, putting in a new prehung unit is often easier than working around an old frame.
7. Double Doors: Installing a pair of doors (like French doors or standard double doors – see Double Doors vs. French Door) requires precise alignment between the two panels. Prehung units for double doors ensure this alignment is correct from the factory.

Measuring for a Prehung Door:

• Measure the Rough Opening (RO) in the wall:
  • Width: Between the vertical framing studs (top, middle, bottom – use smallest).
  • Height: From the subfloor (not finished floor) to the bottom of the header beam above.
  • Wall Thickness (Jamb Depth): Usually 4-9/16″ for 2×4 walls or 6-9/16″ for 2×6 walls.
• Goal: Order a prehung unit designed to fit that specific RO size and wall thickness. Check standard average door dimensions and their typical RO requirements.

Common Prehung Mistakes: Not measuring the RO correctly; not checking wall thickness; installing the unit out of plumb or level (leading to operation problems despite the pre-hung advantage!); insufficient shimming.

Special Considerations: More Factors to Weigh

• Exterior vs. Interior Applications: As emphasized, prehung is strongly recommended for exterior due to integrated weather sealing. For interior doors, the choice is more flexible based on frame condition and DIY skill, as detailed in Prehung Interior Doors vs Slab: Which is Better for Your Home?.
• Accessibility (ADA): Needs wider doorways (typically 36″ door for 32″ clear width). Modifying openings often favors installing a new prehung unit sized correctly.
• Smart Locks: Can be installed on either slab or prehung, but ensure door thickness and backset prep are compatible. May require specific drilling.

Professional vs. DIY Installation: Who Does the Work?

• Hire a Pro When: Installing exterior doors (weatherproofing!), working with load-bearing walls, installing heavy doors, needing frame modifications, lacking skills/tools/time, wanting a warranty on installation.
• DIY When: Replacing simple interior prehung doors, maybe replacing interior slabs if skilled/patient, budget is primary concern AND you have capability.
• Hybrid: Have a pro frame the opening or install a tricky exterior prehung frame, then hang/finish the door slab yourself (if skilled).

Maintenance and Long-Term Considerations

• Slab Doors: Need to maintain the door finish. Hardware needs occasional check/lubrication. Performance relies on the existing frame’s condition over time.
• Prehung Doors: Maintain door finish. Check/replace weatherstripping every few years (exterior). Ensure frame remains secure and caulked (exterior). Threshold may need adjustment/care.
• Warranty: Prehung units often have warranties covering the whole system (door + frame). Slab warranty covers only the slab. Installation errors usually void warranties for both types.

Decision-Making Tools: Help Me Choose!

• Project Assessment Questionnaire: Answer questions about your existing frame, skill level, budget, door location to guide your choice.
• Interactive Decision Tree: Click through questions (New wall? Frame damaged? Exterior?) leading to Slab or Prehung recommendation.
• Door Selection Checklist: Printable list covering all factors (size, material, type, install method, budget).
• Cost Comparison Worksheet: Helps calculate total estimated cost for both slab (with pro install estimate) and prehung (with pro install estimate) scenarios.

Expert Interviews and Insights (Example Snippets)

• Contractor: “9 times out of 10 for exterior, prehung is the way. Interior? If the old frame is perfect and the client is handy or budget-driven, a slab works. Otherwise, prehung saves time and callbacks.”
• Designer: “For that perfect custom look or matching historic details, sometimes sourcing or making a specific slab is necessary, then building the frame to suit.”
• DIY Homeowner: “Tried a slab first, spent hours on the hinges. Ripped it out, bought a prehung, done in 90 minutes. Lesson learned!”

Conclusion: Making the Smart Choice for Your Door

Choosing between a door slab and a prehung door boils down to your specific situation:

• Choose a DOOR SLAB if: Your existing frame is in excellent shape, you’re replacing an interior door on a tight budget (and can DIY or find affordable skilled labor), OR you need to match a unique/custom size or style. Remember the installation requires more skill!
• Choose a PREHUNG DOOR if: You’re doing new construction, the existing frame is damaged, it’s an exterior door (highly recommended!), installation ease/speed is important, OR you want a guaranteed integrated system. This is often the best bet for ensuring proper function and sealing, especially for exterior applications.

For most homeowners undertaking common door replacement projects, particularly involving exterior doors or damaged frames, the prehung door offers significant advantages in ease of installation and overall system performance, often justifying the higher initial unit cost.

Take your time assessing your project needs, skills, and budget. Measure carefully, and choose the option that sets you up for a smooth installation and a door that functions beautifully for years to come!

Ready to find the perfect door, whether slab or prehung, standard or custom? Explore our huge selection or design your own custom doors from us to get exactly what you need! Let’s get your project started!