Overview
An exterior entry door is a system: slab, frame, threshold, weatherstripping, hinges, lock prep, glazing, flashing, and the connection to the wall. Material matters, but a good slab in a poorly prepared opening can still leak, bind, or miss its performance target.
Start with steel, fiberglass, or wood, then compare complete prehung units sized for the opening. If the design includes lites or sidelites, review the glass, coatings, and glazing terms rather than treating the glass as decoration. Before changing opening dimensions or egress conditions, check whether a door-replacement permit may be required in the project jurisdiction.
Steel Doors
Steel is the first material to price when the project emphasizes cost control, a painted finish, and a straightforward residential entry. Most residential steel products use a thin metal skin around an insulated core; construction details, edge systems, gauges, finishes, and warranties vary by product line.
Review dent repair, corrosion protection at cut edges and scratches, coastal limitations, glass options, and exposure restrictions. Security should not be inferred from the word “steel”: lock preparation, frame reinforcement, strike attachment, hinges, and wall anchorage all contribute to the assembly. Compare the quoted steel unit with alternatives using the same dimensions, glazing, ratings, hardware, and installation scope.
Fiberglass Doors
Fiberglass is useful when the owner wants low routine upkeep, painted or wood-grain finishes, and a broad range of residential styles. Quality varies from flat commodity skins to detailed molded panels, so evaluate the actual sample rather than the material label.
Check the warranty for dark finishes, direct sun, storm-door combinations, coastal exposure, and required overhangs. Also compare frame material, threshold, weatherstripping, edge construction, glass package, and hardware reinforcement. Fiberglass is often the balanced residential option, but only after the selected product line meets the project’s size, exposure, finish, and service requirements.
Wood Doors
Wood remains the appearance-led choice when species, grain, custom profiles, or historically appropriate details drive the design. It also creates an explicit maintenance plan: all faces and edges need the specified finish, and exposure, drainage, roof cover, and manufacturer instructions matter.
Price the whole commitment, including factory finishing, site touch-up, periodic inspection, and future refinishing. Ask how the warranty treats direct weather, dark stains, and insufficient overhang. Engineered-core and veneered doors may behave differently from solid-wood construction, so identify the exact build rather than writing only “wood door” in the scope.
Slab vs Prehung, Install, and Security
A slab-only replacement reuses the existing frame and demands accurate hinge, lock, edge, and clearance work. A prehung unit supplies the slab in a new frame with its threshold and weatherstripping, which is usually the clearer scope when the old frame is damaged, out of square, or due for replacement.
The gaps between door units and framed rough openings can be major sites of uncontrolled air leakage. DOE-funded guidance says to seal rough-opening gaps with caulk, low-expansion window-and-door foam, or closed-cell backer rod rather than relying on fibrous insulation alone. It also warns that ordinary expanding foam can distort jambs and cause operating problems. See the Building America Solution Center guidance.
Air sealing does not replace exterior water management. Follow the door manufacturer’s sill-pan, flashing, sealant, fastener, and integration details. For security, specify the lockset, strike reinforcement, fasteners, hinge details, frame construction, and anchorage instead of assuming the slab material carries the entire load.
FAQ
Which exterior-door material should I price first? Price steel for a cost-led painted entry, fiberglass for a low-upkeep residential entry with more finish choices, and wood when species, grain, customization, or historic character is central.
Should I buy a slab or a prehung door? Reuse a slab only when the existing frame, threshold, weatherstripping, dimensions, and hardware locations are suitable. Choose prehung when replacing the frame or creating a new opening.
How should a glazed entry door be compared? Compare the complete unit: glass safety requirements, privacy, coatings, U-factor, solar gain, frame, seals, and warranty. Do not compare door material while changing the glass package.
What belongs in the installation scope? Include opening preparation, sill and flashing details, shimming and anchorage, low-expansion air sealing, exterior sealant, trim, finish touch-up, hardware adjustment, and final operation and water-management checks.