What to Know Before Buying Prehung Exterior Double Doors
A prehung exterior double door arrives with two door slabs already mounted into a single frame, complete with hinges, weatherstripping, and pre-drilled latch holes. The unit is installed as one piece into the rough opening, which eliminates the alignment challenges of hanging slabs individually.
The main advantages are straightforward: reduced installation labor, consistent spacing between the doors, and factory-applied weatherstripping that performs better than most field-applied alternatives. For a double door, the prehung format matters even more than for a single door because the two slabs must meet precisely at the center astragal—a misalignment of even a few millimeters creates air leaks and latch problems.
Buyers typically choose prehung double doors for entryways, patios, or any opening wider than 48 inches where a single door would feel disproportionate. They improve curb appeal, allow wider passage for furniture and equipment, and provide better natural light when configured with glass panels.
Types of Prehung Exterior Double Doors: In-Swing vs. Out-Swing
The most fundamental decision is swing direction, as it affects the frame design, hardware, and weather exposure.
In-swing doors open into the interior. The door slab sits inside the frame, which means the exterior face is flush with the outside wall. This configuration protects the hinges from weather exposure and allows for standard interior floor coverings to meet the threshold without special transitions. The main drawback is that in-swing doors consume interior floor space and can conflict with furniture placement or interior lighting fixtures.
Out-swing doors open to the exterior. They are common in commercial settings and increasingly specified for residential projects where interior space is tight. Out-swing doors require hinge pins on the exterior, which raises security considerations—hinge-pinned models are vulnerable to pin removal unless the manufacturer uses non-removable pins or security studs. The threshold also requires a beveled sill to shed water effectively, and the bottom weatherstrip must compress against the sill surface rather than rely on gravity.
For residential applications, in-swing is the safer default choice unless the interior layout makes it impractical. Out-swing makes sense for screen porches, pool enclosures, or areas where wind pressure on the exterior face would force an in-swing door open.
Sizing Guide: Standard and Custom Dimensions
The most commonly referenced size is the prehung 36×80 exterior door, which means each individual door slab measures 36 inches wide by 80 inches tall. Two 36-inch slabs side by side create a 72-inch-wide opening, which is the standard double door width.
Common configurations include:
| Door Width (each slab) | Total Opening Width | Typical Use |
|---|---|---|
| 30 inches | 60 inches | Narrow entries, secondary doors |
| 32 inches | 64 inches | Standard residential double doors |
| 36 inches | 72 inches | Most common, allows 36-inch clearance for furniture |
| Custom widths | Varies | Commercial or luxury residential |
The rough opening must be larger than the door unit itself. For a 72-inch-wide double door, the rough opening should typically measure 74 to 75 inches wide to allow for shimming and leveling. The height allowance is usually 1.5 to 2 inches above the door height, depending on the threshold design.
Height variations also exist. The standard 80-inch height works for most interior floor-to-ceiling dimensions, but 84-inch and 96-inch heights are available for taller entryways. Custom sizing is common for double doors because the opening width often corresponds to architectural features rather than standard increments.
When measuring, account for the following: the rough opening must be plumb, level, and square. Out-of-square openings require shimming, which reduces the effective adjustment range. For retrofit projects, measure the existing rough opening rather than the old door frame—the new unit may have different frame dimensions.
Material Comparison: Wood, Fiberglass, Steel, and Aluminum
The material determines durability, maintenance, insulation, and cost. Each option involves trade-offs that matter depending on the project context.
Wood remains the traditional choice for its appearance and workability. It takes paint and stain well, can be routed for custom panel designs, and offers a warm aesthetic that other materials struggle to replicate. The downsides are significant: wood expands and contracts with humidity changes, which can cause the door to stick or the frame to shift. It requires periodic refinishing—typically every two to three years for exterior exposure—and is vulnerable to rot at the bottom edge and around glass panels if the finish fails. Solid wood doors are also the heaviest option, which affects hinge selection and long-term sagging risk.
Fiberglass has become the dominant choice for exterior doors because it addresses most of wood’s weaknesses. A fiberglass door is dimensionally stable, meaning it does not expand or contract significantly with temperature and humidity changes. It resists rot, insects, and UV damage. The surface can be painted to match any color scheme, and modern manufacturing embosses wood grain patterns that are difficult to distinguish from real wood at a distance. Fiberglass doors are also better insulators than wood of the same thickness because the core is typically polyurethane foam. The main limitation is that fiberglass cannot be field-trimmed easily—cutting it requires specialized tools and leaves exposed edges that need sealing.
Steel offers the highest strength-to-weight ratio and the lowest cost per square foot. A steel door with a polyurethane core provides good insulation and excellent security. The drawbacks include susceptibility to dents from impacts, rust at the bottom edge if the galvanized coating is scratched, and limited design flexibility—steel doors are typically available in fewer panel configurations than wood or fiberglass. The exterior surface conducts heat and cold, which can create condensation issues in extreme climates.
Aluminum is the standard for commercial applications and is gaining traction in residential projects, particularly for modern architectural styles. Aluminum frames are strong, lightweight, and corrosion-resistant. The key advantage is the thermal-break design: the frame is constructed with a polyamide strip separating the interior and exterior aluminum sections, which prevents heat transfer through the metal. Aluminum doors can accommodate large glass panels with narrow sightlines, making them ideal for maximizing natural light. The trade-off is that aluminum doors are typically more expensive than steel and offer less design flexibility than wood or fiberglass in terms of panel configurations.
Prehung Exterior Double Doors: Comparison Table
| Factor | Wood | Fiberglass | Steel | Aluminum (Thermal-Break) |
|---|---|---|---|---|
| Insulation (relative) | Moderate | High | High | Moderate to High |
| Maintenance | High (refinish every 2-3 years) | Low (paint as needed) | Low (touch up scratches) | Low |
| Durability | Susceptible to rot and warping | Excellent dimensional stability | Dents and rust risk | Excellent corrosion resistance |
| Weight | Heavy | Moderate | Moderate | Light |
| Design flexibility | High (custom panels, shapes) | Moderate (embossed grain) | Limited | Moderate (modern styles) |
| Relative cost | High | Moderate | Low | High |
| Best for | Traditional architecture, custom designs | Most residential applications | Budget projects, security priorities | Modern architecture, large glass areas |
How to Choose the Right Prehung Double Door for Your Project
Start with the opening dimensions and swing direction, then evaluate materials against the local climate and building code requirements.
Climate considerations. In cold climates, look for doors with low U-factor ratings and check that the frame includes a thermal break. The U-factor measures heat transfer—lower is better. A U-factor below 0.30 for the entire door unit is considered good for cold climates. In hot, humid climates, focus on the door’s ability to resist moisture infiltration and check the weatherstripping quality. In coastal areas, prioritize corrosion-resistant hardware and materials that withstand salt exposure.
Egress and building codes. Double doors must meet local egress requirements, which typically specify a minimum clear opening width. The International Residential Code (IRC) requires a minimum clear opening of 32 inches wide for egress doors. For a double door, this means at least one of the two doors must provide that clear opening when the other is closed and locked. If the active door is 36 inches wide, it will typically meet this requirement. Verify that the astragal design does not reduce the clear opening below the required dimension.
Locking and security. Double doors require a multipoint locking system or a combination of locks to secure both the active and inactive doors. The astragal—the vertical strip where the two doors meet—plays a critical role. A fixed astragal is permanently attached to the inactive door and provides a solid strike surface for the active door’s locks. A removable astragal allows both doors to open fully but offers less security. For exterior applications, a fixed astragal with flush bolts (top and bottom) on the inactive door is the standard configuration.
Energy efficiency. Beyond the door material, examine the glass. Double-pane glass with low-E coating is standard for exterior doors. Triple-pane glass is available but adds weight and cost. The frame’s weatherstripping quality matters as much as the glass—look for compression seals at the top and sides and an adjustable threshold at the bottom to accommodate floor variations.
Budget planning. The total cost includes the door unit, hardware, installation, and any modifications to the rough opening. Door units range from budget steel models to premium wood or aluminum units with a wide price spread. Installation labor for a prehung double door typically runs higher than a single door because the unit is heavier and requires more precise leveling. If the rough opening needs structural modification, budget for framing and flashing work.
Additional Considerations: Outswing Options and Installation Tips
Prehung outswing exterior double doors require specific attention to the threshold and weatherproofing. Because the door seals against the exterior face of the frame, the threshold must have a sloped profile that directs water away from the interior. The bottom weatherstrip should be adjustable to maintain contact with the threshold as the building settles.
For outswing units, verify that the hinges are rated for exterior use and that the hinge pins are non-removable or protected by security studs. Some manufacturers offer hinge-side security plates that prevent the door from being lifted off the hinges.
Installation considerations for prehung units. The primary advantage of prehung doors is that they arrive with the frame square and the doors aligned. However, the rough opening must still be properly prepared. Key points:
- The rough opening should be flashed at the sill before the unit is set in place. This prevents water from wicking into the framing.
- Use shims at the hinge locations and latch locations, not just along the bottom. This distributes the door’s weight and keeps the frame from bowing.
- Check that the frame is square before securing it. A prehung unit that is forced into an out-of-square opening will bind or leak.
- For concrete floors, use a sill pan and sealant to create a watertight barrier between the threshold and the floor.
Retrofit vs. new construction. Retrofitting a prehung double door into an existing opening is more complex than new construction because the rough opening may not match the new unit’s dimensions. Measure the existing frame’s exterior dimensions and compare them to the new unit’s frame dimensions. If the opening is too large, you will need to add framing; if too small, you may need to enlarge the opening, which requires structural assessment.
What to Look for in a Manufacturer or Supplier
When evaluating suppliers, focus on the factors that affect the installed performance rather than the surface appearance.
Frame construction. The frame must be structurally rigid enough to support two doors. Look for frames made from the same material as the doors—fiberglass frames for fiberglass doors, aluminum frames for aluminum doors—rather than wood frames with a different door material. The frame’s cross-section should include a thermal break for aluminum, or a solid core for fiberglass and wood.
Weatherstripping quality. The weatherstripping should be compression-type for the top and sides, and the threshold should have an adjustable bottom seal. Ask whether the weatherstripping is replaceable—it will eventually wear out, and the ability to replace it without removing the door matters for long-term maintenance.
Hardware and astragal. Confirm that the astragal is designed for the specific door configuration. A fixed astragal with flush bolts is the most secure option for exterior use. The locking system should be rated for exterior applications and ideally meet ANSI/BHMA Grade 2 or better.
Customization capability. Double doors are often specified for non-standard openings. A manufacturer that can produce custom sizes, accommodate different swing configurations, and offer varied glass options provides more flexibility than one with only standard sizes.
Pre-shipment quality control. For international sourcing, ask about the inspection process. Reputable manufacturers test for air-tightness, water-tightness, and wind resistance before shipping. These tests are particularly important for exterior doors because the installed performance depends on the frame and weatherstripping working together.
As a manufacturer of thermal-break aluminum doors and windows, our approach to prehung exterior double doors centers on the frame system. We build the aluminum frame with a polyamide thermal break, which prevents the metal from conducting heat between the interior and exterior. This matters for double doors because the wide frame surface area creates a larger thermal bridge than a single door.
We also address the astragal as a structural component rather than an accessory. Our double door frames use a fixed astragal with flush bolts, and we can adjust the profile structure to match local building codes in your target market. For buyers sourcing from overseas, we provide full customs documentation, packing lists, and proforma invoices. Our pre-shipment inspection includes air-tightness and water-tightness tests, and we support both FCL and LCL shipments.
The advantage of working directly with a factory is that you can specify custom dimensions, glass options, and hardware configurations without the markup of a middleman. If you have a project with specific requirements, the conversation starts with the rough opening dimensions and the performance criteria you need to meet.
Frequently Asked Questions
What is the rough opening for a 60-inch double door?
A 60-inch-wide double door (two 30-inch doors) typically requires a rough opening of 62 to 63 inches wide. The height allowance is usually 1.5 to 2 inches above the door height. Always check the manufacturer’s specifications, as frame dimensions vary between brands.
Are double doors energy efficient?
Double doors can be energy efficient, but they have more surface area and more joints than a single door, so the potential for air leakage is higher. Look for doors with low U-factor ratings, compression weatherstripping, and a thermal-break frame if using aluminum. The astragal seal is critical—a poorly sealed astragal negates the performance of the rest of the door.
Do double doors meet egress requirements?
Most double doors meet egress requirements if at least one door provides a clear opening of at least 32 inches wide when the other door is locked. The clear opening is measured with the door open at 90 degrees, from the face of the door to the stop on the strike side. Verify the active door’s width against your local code.
Can I install a prehung double door myself?
Installing a prehung double door is possible for an experienced DIYer, but the unit is heavy—often exceeding 150 pounds—and requires two people to handle safely. The rough opening must be square and plumb, and proper flashing is essential to prevent water damage. If the opening is out of square by more than 1/4 inch, professional installation is recommended.
How much does a prehung exterior double door cost?
Costs vary widely based on material, size, glass configuration, and hardware. Steel units are the most budget-friendly, while fiberglass sits in the mid-range, and wood or aluminum units with custom features cost the most. Installation labor adds significantly to the total, particularly if the rough opening requires modification. Request itemized quotes from manufacturers to compare unit prices against installation costs.
