Exterior Doors

Homeowner Summary

Exterior doors serve three fundamental purposes: security, weather protection, and energy efficiency. A solid, well-fitted exterior door keeps intruders out, weather at bay, and conditioned air inside. A poorly fitted or deteriorating door does none of these well, and you feel it in drafts, noise, and higher energy bills.

Most homes have two to four exterior doors: a front entry door, a back or side door, and possibly a garage entry door and a patio or sliding glass door. The front entry door also has an outsized impact on curb appeal -- real estate professionals consistently rank it as one of the highest-return home improvements.

Entry doors come in three main materials: fiberglass, steel, and wood. Patio doors are primarily sliding glass or hinged (French door) configurations. Each material has distinct trade-offs in security, insulation, maintenance, and aesthetics. A quality exterior door with professional installation costs $500 to $3,000, and should last 20-50 years depending on material and exposure.

How It Works

An exterior door system includes several components that work together:

Door slab: The door itself. Solid-core construction for security and insulation. Entry doors may be flush (flat) or paneled. Fiberglass and steel doors have a foam insulation core (polyurethane or polystyrene) sandwiched between outer skins.

Frame and jamb: The wooden or composite structure that holds the door in the wall opening. The frame includes the head (top), two side jambs, and the sill (bottom). The sill is the most vulnerable component because it contacts water directly.

Threshold and sill pan: The threshold is the raised strip at the bottom of the door opening that you step over. It creates a barrier against water, air, and pests. The sill pan (or pan flashing) beneath the threshold directs any water that penetrates back to the exterior.

Weatherstripping: Compressible seals along the top and sides of the frame (typically magnetic or compression type on steel doors, foam or fin-seal on fiberglass and wood). The door sweep or bottom seal closes the gap at the threshold.

Hardware: Hinges (three for standard height, four for 8-foot doors), lockset, deadbolt, and optional smart lock. Strike plates with 3-inch screws into the framing are critical for security -- most break-ins exploit weak strike plates with short screws.

Glass (lites): Many entry doors and all patio doors include glass panels. These are IGUs (insulating glass units) identical in technology to windows -- double or triple pane, Low-E coated, gas-filled.

Maintenance Guide

DIY (Homeowner)

• Inspect weatherstripping annually: Close the door on a piece of paper. If it slides out easily, the weatherstripping is compressed or worn. Replace it.
• Adjust the door sweep: The bottom seal should contact the threshold evenly across its width with light pressure. Adjust screws to lower or raise.
• Lubricate hinges yearly: Silicone spray or white lithium grease on hinge pins. This prevents squeaking and binding.
• Clean and lubricate locks: Spray graphite powder or lock-specific lubricant into the keyway annually. Do not use WD-40 in locks -- it attracts dust.
• Inspect the threshold and sill: Look for cracks, gaps, or rot. Water damage here is common and critical.
• Wood doors: inspect finish annually. Touch up bare spots, sand and refinish every 2-3 years for varnished doors or 5-7 years for painted doors. South and west-facing wood doors degrade fastest.
• Fiberglass doors: Clean with mild soap and water. Can be stained or painted like wood. Apply UV-protective finish if stained.
• Steel doors: Touch up scratches and chips immediately with matching paint to prevent rust. Clean with soap and water.
• Patio/sliding doors: Clean the track with a vacuum and stiff brush. Lubricate the track with silicone spray. Adjust the roller height screws if the door drags.
• Test deadbolt engagement: The bolt should extend fully into the strike plate without forcing. If it doesn't, the door may have shifted (settling) or the strike plate needs adjustment.

Professional

• Door replacement: When the slab is warped, rotted, or damaged beyond repair. Professional installation ensures proper flashing, shimming, and weathersealing.
• Frame and sill repair: Rotted sills are common. Epoxy consolidation works for minor damage; full sill replacement for extensive rot.
• Threshold replacement: Aluminum or composite thresholds wear out and lose their seal. Replacement requires careful fitting.
• Smart lock installation: While many are DIY, professional installation ensures proper alignment, wiring (if hardwired), and integration with home security systems.
• Patio door track/roller replacement: When sliding doors become difficult to operate despite cleaning and adjustment.
• Security upgrade: Adding reinforced strike plates, hinge shields, and door barricade hardware.

Warning Signs

• Visible daylight around the door perimeter: Weatherstripping has failed or the door is out of alignment.
• Drafts felt near the door: Energy loss and comfort issue. Use an incense stick to trace the leak path.
• Door sticking or binding: Swelling (wood, moisture), settling, or hinge wear. Seasonal swelling is normal for wood; persistent sticking is not.
• Difficulty locking the deadbolt: The door or frame has shifted. Forcing the lock will eventually damage it.
• Rust spots on steel doors: The paint has been breached. Rust spreads under the paint surface.
• Delamination (fiberglass or steel): The outer skin is separating from the foam core. Typically caused by prolonged sun/heat exposure without proper finishing.
• Water on the interior sill after rain: Threshold seal failure, missing sill pan, or flashing deficiency.
• Condensation on glass lites: IGU seal failure, same as windows.
• Soft or spongy wood at the sill or lower jamb: Rot from chronic water exposure.
• Door won't latch without lifting or pushing: Hinge wear or settling. The door is sagging.

When to Replace vs Repair

Repair when:

• Weatherstripping or door sweep needs replacement (inexpensive, high impact).
• Minor wood rot at the sill (epoxy consolidation).
• Scratches or minor dents in steel (fill, sand, paint).
• Hardware failure (lockset, deadbolt, hinges can be replaced independently).
• Glass lite has failed seal (IGU replacement possible on most doors).

Replace when:

• The door slab is warped, cracked, or structurally compromised.
• Extensive rot in the frame that epoxy cannot address.
• The door is a hollow-core type used as an exterior door (security and insulation failure -- common in older homes).
• Upgrading from a non-insulated to an insulated door for energy efficiency.
• Security concerns (upgrading to a steel or reinforced fiberglass door).
• The door is more than 25 years old and exhibiting multiple symptoms.

Pro Detail

Specifications & Sizing

Entry Door Materials

| Material | R-value | Security | Maintenance | Lifespan | Cost Range | |----------|---------|----------|-------------|----------|------------| | Fiberglass (foam core) | R-5 to R-7 | Good | Low (paint/stain every 8-10 yrs) | 30-50 years | $500 - $2,500 | | Steel (foam core, 20-24 ga) | R-5 to R-7 | Excellent | Low (touch up scratches) | 25-40 years | $300 - $1,500 | | Solid wood (hardwood) | R-2 to R-3 | Good | High (refinish every 2-5 yrs) | 30-50+ years | $1,000 - $5,000+ | | Wood with aluminum cladding | R-2 to R-3 | Good | Moderate | 30-40 years | $1,500 - $4,000 |

Standard Sizes

| Door Type | Standard Width | Standard Height | Notes | |-----------|---------------|-----------------|-------| | Single entry | 36 in (914 mm) | 80 in (2032 mm) | Code minimum 32 in clear opening | | Double entry | 60-72 in | 80 in | One active, one fixed (astragal) | | 8-foot entry | 36 in | 96 in | Premium homes, requires 4 hinges | | Sliding patio | 60-72 in (OX or OXO) | 80 in | OX = one fixed, one sliding | | French patio | 60-72 in | 80 in | Both panels operable |

Hardware Specifications

| Component | Specification | Security Rating | |-----------|--------------|----------------| | Deadbolt throw | 1 inch minimum | ANSI/BHMA Grade 1 (best) | | Strike plate screws | 3 inches minimum (into framing) | -- | | Hinge screws | At least one 3-inch screw per hinge (into framing) | -- | | Lock grade | ANSI/BHMA Grade 1, 2, or 3 | Grade 1: 800K cycles, Grade 2: 400K, Grade 3: 200K | | Smart lock | ANSI/BHMA Grade 2 minimum, UL 437 pick-resistant | Z-Wave, Zigbee, Wi-Fi, or Thread/Matter |

Smart Lock Features

| Feature | Description | |---------|-------------| | Auto-lock | Locks after a set time period (30 sec to 5 min) | | Remote access | Lock/unlock via smartphone app (requires Wi-Fi or hub) | | Access codes | Unique codes for family, guests, service providers | | Activity log | Timestamped record of all lock/unlock events | | Integration | Works with Alexa, Google Home, Apple HomeKit, or Matter | | Backup entry | Physical key or keypad in case of battery failure | | Battery life | 6-12 months typical (4 AA or lithium CR123A) |

Common Failure Modes

1. Weatherstripping compression set: After 5-8 years, foam and rubber weatherstripping loses its resilience and no longer seals. Magnetic weatherstripping (common on steel doors) lasts longer.
2. Sill rot: The most vulnerable point. Water pools on the threshold and wicks into wood sills. Composite or aluminum sills last much longer.
3. Door sag: Heavy doors (especially solid wood and steel) cause hinge screws to loosen over time. The door drops on the latch side, causing binding and poor seal.
4. Fiberglass/steel delamination: Prolonged direct sun (especially south/west exposure) without proper finishing causes the outer skin to separate from the foam core. Storm doors can exacerbate this by trapping heat (150-180 degrees F in the air space).
5. Smart lock battery failure: Average battery life is 6-12 months. Low-battery warnings should be heeded promptly. Always maintain the physical key backup.
6. Patio door roller failure: Nylon or steel rollers wear out after 10-15 years. The door becomes increasingly difficult to slide.
7. Glass lite seal failure: IGU between panes fogs, losing insulation and clarity. Same mechanism as window seal failure.

Diagnostic Procedures

1. Daylight test: In a darkened room during daytime, look around the door perimeter for light leaks. Mark locations.
2. Paper test: Close the door on a sheet of paper at multiple points along both jambs and the head. Consistent resistance means good seal. Easy slide-out means poor seal at that point.
3. Smoke pencil test: On a windy day, trace an incense stick around the door perimeter inside. Smoke deviation reveals infiltration points.
4. Square check: Measure diagonals of the door opening. If they differ by more than 1/8 inch, the frame is out of square (settling or improper installation).
5. Hinge check: Open the door 90 degrees and lift the handle end. Movement greater than 1/8 inch indicates loose hinges or worn hinge pins.
6. Threshold seal test: Pour a small amount of water on the exterior side of the threshold during a dry period. If it appears inside within minutes, the threshold seal or sill pan has failed.
7. Lock alignment: With the door open, extend the deadbolt. It should move smoothly and fully. Close the door and engage the deadbolt -- it should engage without forcing. Misalignment indicates frame movement.

Code & Compliance

• IRC R311.2: At least one exterior door must be a side-hinged door with a minimum clear opening of 32 inches wide and 78 inches high (egress requirement).
• IRC R311.4.3: Landing required on each side of an exterior door. Must be at least the width of the door and 36 inches in the direction of travel. Exception: the top landing at the exterior can be up to 7-3/4 inches below the interior floor (step-down landing) for sliding doors only.
• IRC R612 / R310: Glazing in doors must be safety glazing (tempered or laminated) per IRC R308.
• ADA compliance: For aging-in-place or accessibility, exterior doors should provide 32 inches minimum clear opening (36-inch door achieves this), lever handles, and a maximum threshold height of 1/2 inch (3/4 inch for sliding doors).
• Energy code (IECC): Exterior doors are part of the thermal envelope. Opaque door U-factor requirements vary by climate zone (typically U <= 0.17 to 0.21 for opaque, U <= 0.30 to 0.35 for doors with glazing).
• Fire code: Door from attached garage to living space must be 20-minute fire-rated (1-3/8 inch solid wood, steel, or listed assembly). Self-closing device required.
• Wind code (hurricane zones): Exterior doors in HVHZ must meet impact resistance requirements (large missile test per ASTM E1886/E1996 or Miami-Dade TAS 201/202/203).

Cost Guide

| Service | Typical Cost | Factors | |---------|-------------|---------| | Fiberglass entry door (installed) | $800 - $2,500 | Size, glass, hardware, finish | | Steel entry door (installed) | $500 - $1,500 | Size, glass, hardware | | Solid wood entry door (installed) | $1,500 - $5,000 | Species, carving, glass, finish | | Sliding patio door (installed) | $1,000 - $3,000 | Size, material, glass type | | French patio door (installed) | $1,500 - $4,000 | Material, glass, hardware | | Storm door (installed) | $200 - $600 | Material, glass options | | Deadbolt (Grade 1, installed) | $100 - $250 | Brand, finish | | Smart lock (installed) | $200 - $500 | Brand, connectivity, features | | Weatherstripping replacement | $50 - $150 | Type, door size | | Threshold replacement | $100 - $300 | Material, fitting complexity | | Door sill repair (epoxy) | $150 - $300 | Extent of damage | | Frame/jamb replacement | $300 - $800 | Extent, material |

Energy Impact

Exterior doors affect energy efficiency through insulation, air leakage, and glass:

• Insulated doors: A foam-core fiberglass or steel door provides R-5 to R-7, compared to R-2 to R-3 for solid wood. The improvement is modest in absolute terms because doors represent a small area, but air sealing matters more.
• Air infiltration: A poorly weatherstripped exterior door can leak 5-15 CFM of air. Four leaky doors leak as much air as an open window. Weatherstripping replacement is one of the highest-ROI energy improvements a homeowner can make.
• Glass in doors: Entry doors with half-glass or full-glass panels have significantly lower insulation values than solid doors. The glass portion performs the same as a window (U-factor 0.25-0.55). Limit glass area on north-facing doors in cold climates.
• Patio doors: Large glass area makes these the weakest thermal link. Triple-pane Low-E argon sliding doors (U-factor ~0.20) are worth the premium in cold climates.
• Storm doors: A storm door adds an insulating air space, reducing heat loss by 25-50% through the primary door. Best ROI on older or poorly insulated doors. Caution: storm doors on south/west-facing fiberglass or steel doors can trap heat and cause delamination.
• Entry door replacement ROI: The DOE estimates replacing an old, poorly sealed door saves $50-$100/year in energy. The payback is primarily in comfort and security.

Shipshape Integration

• Security monitoring integration: SAM tracks door hardware type, smart lock status, and security configuration. Smart lock activity logs can be integrated into the home's security timeline.
• Age and condition tracking: SAM records door material, installation date, and condition. As doors approach end-of-life, SAM alerts homeowners and generates dealer recommendations.
• Weatherstripping reminders: SAM schedules annual weatherstripping inspection reminders, typically in fall before heating season. Includes instructions for the paper test.
• Exterior photo analysis: SAM can identify visible door issues from photos -- peeling finish, visible rust, sagging, damaged weatherstripping, and rotted sills or frames.
• Home Health Score: Door condition contributes to the security sub-score (hardware, frame integrity) and the energy efficiency sub-score (weatherstripping, insulation, glass). Deficiencies in either area reduce the overall score.
• Dealer actions: SAM generates service recommendations for door repair, hardware upgrade, or replacement based on age, condition, and identified issues. Priority is elevated for security-related deficiencies.
• Storm preparedness: In hurricane zones, SAM verifies whether exterior doors meet impact-resistance requirements and alerts homeowners to protection needs before storm season.
• Smart home integration: SAM can incorporate smart lock data (battery status, access logs, auto-lock settings) into the home management dashboard, providing a unified view of home security.