A steel door can look beautifully simple in a visual, then become complicated the moment it reaches a drawing package. This architect guide steel specifications article focuses on the decisions that protect the original design intent: sightlines, sizes, glazing, thermal performance, fire rating and the details around the opening. Get these right early and the finished door feels considered rather than compromised.
Start with the door’s job, not its appearance
Steel-framed glazing is often selected for its narrow profiles and strong graphic lines. It can divide a kitchen and hallway, create a dramatic entrance, or bring daylight through a commercial interior without closing it off. But the same black-framed appearance can describe very different systems.
An internal hinged door does not face rain, heat loss or the same security demands as an external entrance. A fire-rated door may need a tested frame, glazing build-up, seals, ironmongery and installation method that differ materially from a standard internal screen. Start by defining where the door sits, what it separates and what it must achieve.
For each opening, establish whether it is internal or external; hinged, sliding, pivoting or fixed; single or double leaf; glazed fully or partly; and subject to fire, acoustic, security or thermal requirements. This avoids specifying a visually attractive profile that cannot deliver the required performance.
Architect guide steel specifications: define the system
A specification should identify a complete system, rather than simply calling for “steel doors with slim frames”. The frame, leaf, glass, hinges, locks, seals and fixings work together. Substituting one element can affect appearance, operation and certification.
Internal steel doors and screens
Internal steel systems are suited to spaces where daylight and separation need to coexist. They are particularly effective between kitchens, reception rooms, studies and corridors, or in hospitality and workplace interiors where clear zoning matters.
Specify the intended configuration with enough detail to be priced accurately. State the number of leaves, opening direction, handing, transom and mullion layout, handle position, threshold expectation and finish. If the design includes an arch, curved head or non-standard division pattern, show it clearly on elevation drawings rather than relying on a written description.
Glazing is not a secondary choice. Clear toughened safety glass keeps the look minimal, while reeded, fluted or obscured glass introduces privacy. Laminated options may be appropriate where enhanced safety, acoustic control or a particular visual effect is needed. The exact glass specification depends on panel size, location and applicable safety requirements.
External steel doors and windows
External steel must deal with a harsher brief. For a London renovation, that can mean wind-driven rain, changing temperatures, exposed elevations and the need to connect cleanly with existing masonry or modern insulation build-ups.
A thermally broken steel system separates the interior and exterior sections of the profile to reduce heat transfer. It is the right starting point for external doors and windows where thermal performance matters. Do not assume a steel profile that works internally can be adapted for an external opening.
The specification should set out the required thermal target, glazing performance, weather performance, drainage approach and threshold detail. Consider whether the door is exposed or sheltered, whether it opens onto a terrace, and how the finished floor levels meet inside and out. A flush threshold may be desirable, but it needs proper drainage and coordinated build-up details to perform well.
Fire-rated steel doors
Where a fire-resisting barrier is required, the rating must relate to the complete tested or assessed doorset. It is not enough for the steel frame alone to be described as fire-rated.
E30 generally refers to 30 minutes of integrity, while EI30 and EI60 refer to integrity and insulation for 30 or 60 minutes respectively. The appropriate classification comes from the fire strategy, Building Regulations requirements and the project’s fire consultant or approved inspector. The glass, intumescent seals, closer, hinges, lock and frame construction must all be compatible with the certified configuration.
Be precise about the required rating, whether the door needs to be self-closing, the direction of escape, vision panel requirements and any access-control hardware. Changes made after approval, including alternative handles or hold-open devices, should be checked against the doorset evidence before ordering.
Sizes, proportions and structural reality
Steel earns its place in a scheme because it can create fine sightlines around generous areas of glass. That does not mean every opening should be pushed to its visual limit. Leaf weight, hinge capacity, deflection, glazing weight and day-to-day use all shape what is practical.
Large pivot doors can be striking, especially on entrances and wide internal openings, but they need room for the pivot position, swing arc and floor or ceiling support. Sliding doors remove swing space, yet require a clear run beside the opening and careful consideration of soft-close operation, meeting stiles and privacy when closed. Double doors offer symmetry and a generous clear opening, although the inactive leaf and locking arrangement should be resolved early.
Provide finished structural opening dimensions, not only nominal door sizes. Also identify whether dimensions are taken from finished floor level, structural floor level or another agreed datum. Tolerances matter. A bespoke frame cannot compensate indefinitely for walls that are out of plumb or floors that rise across the opening.
Specify finish with the same care as the profile
The familiar black steel look remains popular because it gives definition without visual weight. Yet RAL colour, sheen level and coating type can alter the result considerably. A matt dark finish feels different from a textured black powder coat, and both will show against pale plaster in different ways.
For internal projects, powder coating is often selected for its consistent appearance and durability. For exterior work, the coating specification must suit the exposure and intended maintenance regime. Coastal conditions, heavy pollution and high-contact commercial settings may call for a more considered finish choice than a sheltered private hallway.
Samples should be reviewed alongside the surrounding materials: timber, stone, brassware, paint and floor finishes. The same is true for ironmongery. A minimal pull handle, lever handle, lock escutcheon or concealed closer can change the visual rhythm of a door as much as the glazing grid.
Coordinate interfaces before manufacture
Most site problems happen at the edge of the steelwork. The frame needs a stable, suitable substrate. Plasterboard partitions may require reinforcement, masonry openings need accurate preparation, and tiled or stone reveals need agreed tolerance and sequencing.
Coordinate electrical points for access control, magnetic locks, intercoms and automatic operators before the frame is installed. Confirm skirting lines, ceiling details and floor transitions too. A full-height glazed screen often looks best when the head detail is deliberately resolved, rather than filled with an unplanned cover trim.
For external installations, clarify who is responsible for waterproofing at sills, jambs and heads. The steel installer, builder, roofer and glazing contractor may each have a role. The drawings should make those responsibilities visible before work begins.
Write a specification that can be quoted accurately
A clear schedule saves time for the design team and produces a more reliable quote. Alongside drawings, include the opening reference, system type, configuration, dimensions, finish, glazing, ironmongery, performance requirements and installation scope. Photographs of existing openings are useful for refurbishment projects, but they should support measured information rather than replace it.
Avoid copying generic wording from an old specification where the project conditions have changed. A standard internal glazed door clause will not cover an EI60 entrance, and an external thermally broken system should not be priced from a drawing that omits thresholds and drainage.
Artsteel works on made-to-measure steel door and glazing projects, so early drawings and clear performance requirements help turn an architectural idea into a practical, tailored proposal. The best time to test the specification is before finishes are ordered and programme pressure makes every decision more expensive.
A well-specified steel door should still feel effortless when it is complete: slim lines, clean operation, light moving through the space and the right level of performance quietly built into every detail.