We may be compensated if you purchase through links on our website. Our team is committed to delivering honest, objective, and independent reviews on home products and services.
Are you trying to revamp the look of a room in your home? You may just need a new door. Installing a pre-hung interior door can give your home a fresh look and improve its functionality. While it might seem like a big task, with the right tools and some guidance, you can handle it. This Old House expert Tom Silva walks homeowner Justin through the process in the video below, sharing tips to make sure everything fits just right.
Difference Between a Pre-Hung Door and a Slab Door
Before diving into installation, it’s helpful to understand the difference between a pre-hung door and a slab door. A pre-hung door is a complete unit that includes the door, hinges, and frame, all ready to be installed in a rough opening. This makes the installation process quicker and often easier—especially for those less experienced with carpentry.
On the other hand, a slab door is just the door itself—no hinges, no frame. Installing a slab door requires more skill, as you’ll need to fit it into an existing frame, align it properly, and cut out spaces for the hinges and latch.
Pro Tip: Tom Silva, This Old House general contractor, advises: “When replacing a vintage door with a new one, you often have go the custom route to match the 2-to-2½-inch thickness of most older doors.” This is an important consideration if you’re working in an older home and deciding between a prehung unit and a slab replacement.
As This Old House carpenter Nathan Gilbert explained on a recent project, choosing between the two often comes down to what’s already there: “But if I get a prehung door, I’m going to have to pull the trim off both sides, right? I’m going to be throwing away a perfectly good jamb. Then I have to put the jamb in, shim it, trim it, paint it. So there’s a lot of extra work here just to change the door slab.” If your existing jamb and trim are in good shape, a slab door can save significant time and effort.
Types of Pre-Hung Doors
Pre-hung doors are available in various styles and materials, such as the following:
- Solid Wood: These types of doors are sturdy, durable, and offer a high-end look. They’re a good option for soundproofing but cost more and are prone to swelling in humid conditions.
- Hollow Core: These doors are lightweight and budget-friendly, making them great for indoor applications where sound insulation is less critical.
- Solid Core: These composite-filled doors provide better sound insulation than hollow core doors while being more cost-effective than solid wood.
- Fiberglass: Known for their durability and resistance to warping, fiberglass doors are ideal for areas with humidity changes. They can also mimic the appearance of wood.
- Steel: These doors are extremely secure and long-lasting, but they require maintenance to prevent rust and are not as versatile as other materials.
Tools and Materials for Installing Doors
Before you begin, gather the following tools and materials:
- Circular saw
- Door hardware
- Drill/driver
- Hammer
- Level
- Nail gun (optional)
- Screws
- Shims
- Tape measure
Measuring the Door Opening
Measure the width at the top, middle, and bottom of the opening, and measure the height on both sides and in the center. Also, check if the floor is level across the opening. Your rough opening should be about 2 inches wider and taller than the door unit.
Clear the area of any debris, check wall studs for rot or damage, and make sure the new door frame won’t obstruct electrical switches or outlets.
Pre-hung Door Installation Process
Installing a pre-hung door involves several steps. Follow this guide to help you along the way.
Preparing the Doorframe
Use a level to mark spots on both sides of the rough opening. Measure from these marks down to the floor on both the hinge and striker sides, then transfer these measurements to the door jamb. If your floor isn’t perfectly even, especially in older homes, add a spacer to make sure the door sits properly.
Pro Tip: Tom Silva, general contractor on This Old House, explains his approach to checking for level: “I’ll just take my tape measure and I’ll measure down to the floor. So it tells me that the house is out of level and down this way about an eighth of an inch.” His solution? “What I do is I cut that eighth of an inch off of this side. So when the door goes in, the header will be level.”
Fitting the Door
Check if the rough frame is plumb, and add shims as needed. Slide the door into the opening, making sure it’s flush with the wall. Silva shows in his video how to deal with uneven floors by adjusting the door frame for a level installation.
Securing the Door
Pre-drill holes and drive screws through the hinge-side jamb into the framing. Make sure the jamb is plumb before fully securing it. Close the door to check the fit and make any necessary adjustments. Secure the striker side, using shims to maintain an even gap around the door, and add extra screws if needed for stability.
Final Adjustments and Finishing Touches for Your Door
After securing the door, open and close it a few times to check that it operates smoothly. If there are any sticking points, you might need to trim or sand the door edges.
Break off any excess shim material, install trim with a nail gun or hammer, and add door knob hardware. To complete the look, apply caulk around the trim and lightly sand, prime, and paint the wood for a polished finish.
Troubleshooting Common Issues With Doors
Even with careful installation, you may encounter some challenges. Here’s how to address them:
- Door not closing properly: Check that the jamb is plumb and square, and make sure the hinges are seated correctly. You might need to adjust the strike plate.
- Gaps around the door: Adjust shims behind the hinges or reposition the strike plate. Adding weatherstripping can also help create a tighter seal.
- Squeaky hinges: Remove the hinge pins and apply lubricant, tighten any loose screws, or replace worn hinges.
- Sticking points: If humidity is causing the wood to swell, use a dehumidifier or sand the sticking area. For uneven frames, sand the door edges or adjust the frame.
- Loose door knobs: Tighten the screws on the knob’s mounting plate, ensure the latch mechanism works smoothly, and replace old hardware if needed.
Pro Tip: This Old House general contractor Tom Silva likes a gap, or reveal, of about 1/8 to 3/16 inch — the thickness of a nickel — between door and jamb to accommodate seasonal changes. If sticking is localized, shave the high spot down with the door in the open position using a hefty bench plane, taking long, smooth strokes held at a slight angle.
Our Conclusion
Installing a pre-hung interior door is a doable project with the right preparation and a bit of patience. By following these steps and tips from Silva, you can achieve a professional-looking result that enhances both the look and functionality of your home. Take your time, measure carefully, and don’t hesitate to seek help if you need it.
