How do I drill into a lintel above a door or window?

Telling a concrete lintel from a steel one by the dust and the sound, which bit each needs, and the depth limits that matter structurally.

Difficulty: intermediate
Time: 30 min
Read: 3 min
Safety: warning

Short answer

Fine grey dust and slow going means concrete: use an SDS bit and keep the hole shallow, avoiding the bottom 25mm where reinforcement sits. A metallic screech and no dust means a steel lintel: hammer off, sharp cobalt bit, slow speed and cutting oil. If you hit rebar in a concrete lintel, stop and move.

The header above a door or window is one of the few places in a house where a fixing decision has structural consequences, and it is also where most people first meet something their combi drill cannot handle.

Safety

Lintels carry the load above an opening. Do not drill deeply into a concrete lintel without knowing where its reinforcement runs, and never cut or notch one. Cables very commonly run above openings to switches and lights — use a detector and treat the zone above a door as live until proved otherwise.

What you'll need

SDS drill and SDS bits
cobalt HSS bits (optional)
cable and pipe detector
cutting oil (optional)
eye protection

Step by step

Scan for cables first.The zone directly above a door frame carries switch drops and light feeds constantly. Detect across the whole area, not just the point you want.
Work out what the lintel is.Tap it: concrete sounds dull and solid, a steel catnic-type lintel rings slightly. Age helps too — pressed steel lintels are common from the 1970s onwards, concrete before that.
Start a small test hole.A 6mm hole tells you everything. Fine grey powder means concrete. Bright metal filings and an immediate stop mean steel.
For concrete, use SDS.A concrete lintel is dense and often high strength. A combi drill will polish the surface and get nowhere; an SDS goes in cleanly.
Keep concrete holes shallow and high.Reinforcement runs along the bottom of a concrete lintel where the tension is. Fixing into the upper part, and not deeper than you need, avoids it.
Stop immediately if you hit rebar.A sudden metallic grind in a concrete lintel is reinforcement. Cutting it weakens the lintel. Move at least 50mm and start again.
For steel, turn hammer off.Percussion on steel does nothing but skate. Rotation only, a punched centre mark, a sharp cobalt bit, low speed and cutting oil.
Choose a fixing suited to the material.Concrete takes a proper concrete screw or a sleeve anchor. Steel takes a self-drilling or self-tapping screw, or a tapped and bolted fixing.
Consider fixing either side instead.For curtain poles and blinds you rarely need the lintel itself — the brickwork or the frame reveal each side often gives an easier and equally strong fixing.

Tips

Fixing into the masonry either side of an opening is almost always easier than fixing into the lintel itself.
If a 6mm test hole in concrete takes more than a minute with a combi drill, stop and get an SDS. You are only glazing the hole.
Steel lintels take self-tapping screws very well once you have a clean pilot hole in them.

Common mistakes

Assuming the header is brick — It looks like brick from the outside because a soldier course or a brick slip usually faces it. Behind that is concrete or steel, which needs a different bit and a different fixing.
Drilling deep into the bottom edge of a concrete lintel — That is where the reinforcement sits, because the bottom of a beam is in tension. Cutting through it reduces the lintel's capacity.

If it doesn't work

Bit skating with a squealing noise

Cause: Steel lintel with hammer action on — Fix: Turn hammer off, punch a centre mark, use a sharp cobalt bit at low speed with oil.

No progress and fine grey dust

Cause: Concrete, and the drill has no useful hammer energy — Fix: Use an SDS drill with an SDS bit.

Sudden metallic grinding partway into concrete

Cause: Reinforcement bar — Fix: Stop, withdraw, fill the hole and move at least 50mm along or up.

Fixing spins in the hole in concrete

Cause: Hole oversized from a bit that was skating and wandering — Fix: Use a chemical anchor, or move and drill a fresh accurate hole with an SDS bit.

Questions people ask

How do I fix a curtain pole above a window with a steel lintel?

Either self-tapping screws directly into the steel through a pilot hole, or move the bracket up or sideways into brickwork. Long-arm brackets fixed into the reveal are another route.

Is it safe to drill a lintel at all?

A shallow fixing hole in the right part of a lintel is normal practice. Deep holes, notching, cutting and hitting reinforcement are not. If a fixing needs to be deep or heavily loaded, get advice.

What is a catnic lintel?

A common trade name for a pressed and galvanised steel lintel with an L or box profile. It drills like sheet steel — thin, hard and best with a sharp bit and oil.