Steel Door Frames in India: IS 4351 Guide (India 2026)

Pressed steel door frames are the workhorse chowkhat of Indian institutional building — government quarters, schools, hospitals, factories and commercial blocks lean on them because they ship as one welded, dimensionally true unit that is simply built into the masonry and grouted solid. A steel frame is folded from a single sheet into a tubular profile, so it resists termite, fire and warping in ways a timber frame cannot. The trade-off is rust: get the galvanising, grouting and damp-proofing wrong and a steel frame rots from the inside out. This guide covers the profiles, single versus double rebate, the build-in and cement-mortar grouting sequence, corrosion control, where steel frames belong, and indicative ₹ costs — written for the site engineer and fitter, not the catalogue. For the wider door picture see the complete door guide, and for material-by-material comparison the phase pillar on door frames.

What a pressed steel door frame is

A pressed steel frame is made by cold-forming a flat mild-steel (MS) sheet — typically 1.25mm to 1.6mm thick — through rollers and a press brake into a closed profile, then welding the head-to-jamb corners (usually mitred and welded, ground flush). Unlike a timber chowkhat assembled from running-foot sections with mortise-and-tenon joinery, the steel frame arrives as a rigid three-sided (or four-sided, with a sill member) box. The governing standard is IS 4351 (Steel Door Frames), which fixes the profile shapes, sheet thickness, hinge and lock provision, and the lugs/anchors used to tie the frame into masonry.

Because the unit is welded and self-jigging, it holds square far better than an on-site timber frame. That is its single biggest practical advantage: a steel frame that is set plumb and level will stay square, and a leaf hung in it will keep even gaps for decades. The price of that rigidity is that the frame has no give — if the opening or grout is wrong, you cannot plane it out.

Single rebate vs double rebate

The rebate is the recess the leaf shuts into. IS 4351 frames come in two families:

• Single rebate — one check on the inner face; the leaf closes against one stop. Standard for single internal and most external doors.
• Double rebate — checks on both faces, so the leaf seats between two stops. Used for double-leaf doors, for weatherproofing (the second check carries a seal), and where the door must look the same swinging either way. A double-rebate profile is wider and heavier.

The rebate depth is matched to the leaf thickness (commonly 30–40mm for flush/steel leaves) and the rebate width is around 12–15mm, identical in intent to a timber frame's check. Profiles also differ by jamb depth, which must equal the finished wall thickness so the frame sits flush both faces.

Profiles and the IS 4351 family

Frames are designated by the opening they suit — the same modular logic as timber, where 1M = 100mm, so a 10×21 frame fits a 1000×2100mm leaf. Always confirm whether the quoted size is the frame outer, the opening, or the leaf before ordering; for the full size logic see door frame sizes, and for the rebate detail door frame rebate.

Building-in and grouting — the part that matters

A steel frame lives or dies by how it is built into the wall. There are two construction sequences:

1. Built-in during masonry (preferred for blockwork). The frame is stood plumb, level and square in the opening location and braced with temporary struts and a wooden spreader across the bottom (the feet are held at the correct width). The mason then raises the wall around it, bedding the welded lugs/anchors — three per jamb for a ~2.1m frame — into the mortar/concrete courses. The hollow jamb cavities are progressively filled with 1:3 cement mortar or lean concrete so the profile is solid, not a drum.

2. Fixed into a finished opening. Where the opening already exists, the frame is set on packers, plumbed, anchored with fasteners/lugs into the masonry, and the perimeter gap and jamb cavities are grouted with 1:3 cement mortar, packed firmly behind the hinge and lock points.

The grout does three jobs: it locks the frame, it stiffens the thin profile so it cannot bow when the leaf slams, and it bridges the frame to the wall against prising. Pack solid behind every hinge and the lock keep — an ungrouted profile at the hinge will flex and the leaf will drop. Slope or seal the threshold/floor junction so grout and the frame foot are not left standing in water. For the grouting detail and mortar mixes see door frame grouting, and for the anchor/lug layout door frame anchoring in masonry.

Rust, galvanising and the India reality

A mild-steel frame is only as durable as its corrosion protection. The default low-cost frame ships in red-oxide primer only — fine for a dry internal opening, a liability anywhere damp. In Indian conditions — monsoon, coastal salt, splashing in wet areas, and the wall-borne moisture that a poorly damp-proofed wall wicks into the jamb — an unprotected MS frame will bubble its paint, weep rust streaks and corrode at the foot within a few years.

The durable answer is galvanising. A hot-dip galvanised (GI) frame carries a sacrificial zinc coat that protects the steel even at cut edges and scratches; specify GI for any external, coastal, or wet-area frame, and for institutional work meant to last. Then:

• Damp-proof the foot. Never let the frame foot stand in a wet floor or on bare slab — set it above the DPC and seal the floor junction; for the method see door frame damp-proofing.
• Grout solid. Trapped voids hold condensation against bare steel. Full cement grout removes the air gap.
• Finish properly. Over primer/GI, a zinc-rich primer + enamel system; touch up every weld and site-cut. Re-coat in coastal zones.
• Seal the wall junction with silicone externally so water cannot track behind the frame.

Be honest with the client: a primer-only steel frame in a bathroom or a coastal verandah is a false economy. Either galvanise it, or use a WPC, uPVC or RCC frame instead — compare them in WPC door frames and concrete door frames.

Where steel frames make sense

Steel frames excel where security, fire resistance, termite immunity and dimensional consistency matter more than warmth or finish — exactly the institutional and commercial brief. For a high-end home interior, most clients prefer a timber or veneered frame; see wooden door frames. For comparing the whole field before you commit, the door frame material selector walks through the trade-offs.

Indicative cost (India 2026)

Unlike timber (sold by running foot), pressed steel frames are usually priced per complete frame for a standard door size, fabricated and primed; galvanising and grouting/fixing are extra.

These are rules of thumb, not quotes — section thickness, profile width, galvanising and region move them. GST is 18% on the fabricated frame and hardware; labour and any timber components vary. For a like-for-like cross-material number, the door frame cost calculator lets you compare a steel frame against timber, WPC and RCC, and existing detail lives in door frame cost.

Pros and cons at a glance

Pros — dimensionally true and stays square; termite-proof and fire-resistant; strong and secure; fast to build in; standardised under IS 4351; low recurring maintenance once galvanised; ideal for institutional/commercial scale.

Cons — rust-prone if primer-only or poorly damp-proofed; cold, utilitarian appearance; cannot be planed/adjusted once welded; heavy to handle; needs solid grouting and a skilled mason to set plumb and square; harder to re-fix hardware into than timber; not suited to drywall openings (see door frame drywall).

For the broader anatomy that applies across all frame materials, read door frame anatomy; for how any frame is set plumb, level and square in the opening, door frame plumb and level.

Frequently asked questions

Which IS standard covers steel door frames?

IS 4351 (Steel Door Frames) governs pressed steel frames in India — it fixes the profile shapes, sheet thickness, rebate, hinge/lock provision and the lugs used to anchor the frame in masonry. Timber frames fall under IS 4021, and flush leaves under IS 2202.

Single rebate or double rebate — how do I choose?

Use a single rebate for ordinary single-leaf internal and external doors. Choose a double rebate for double-leaf doors, where you want weatherproofing (the second check carries a seal), or where the door should look identical from both faces. Double-rebate profiles are wider and heavier.

Will a steel frame rust in a bathroom or on the coast?

A primer-only mild-steel frame will rust in damp, wet or coastal conditions. Specify a hot-dip galvanised (GI) frame, keep the foot above the DPC, grout it solid so no air gap traps moisture, seal the wall junction, and re-coat periodically. In many wet-area cases a WPC or RCC frame is simpler and cheaper than a galvanised steel one.

How is a steel frame fixed into the wall?

It is built into the masonry and grouted. Set it plumb, level and square with a bottom spreader holding the feet, bed the welded lugs (three per jamb for a 2.1m frame) into the mortar courses or anchor them into a finished opening, then back-fill the hollow profile and perimeter with 1:3 cement mortar or lean concrete, packing solid behind every hinge and the lock keep.

What does a steel door frame cost in India?

As a rule of thumb, a standard primer-only pressed steel frame runs about ₹1,200–2,200 per frame, rising to ₹2,000–3,000 for heavier 1.6mm or double-rebate profiles. Hot-dip galvanising adds roughly 20–40%, and building-in plus cement grout adds ₹300–800 in labour and materials. GST is 18% on the fabricated frame.

Can I plane or trim a steel frame to fit?

No. Once welded and grouted, a steel frame is fixed — you cannot plane it like timber. That is exactly why it must be set true: get the opening, packing and grout right so the frame is plumb, level and square before the mortar sets, because there is no adjusting it afterwards.