Fixing above a window: concrete and steel lintels

Learn to identify a window lintel's material and drill and fix into concrete or steel safely.

FL-01Understand what a lintel isA lintel is the structural beam directly above a window or door opening. It carries the weight of the wall above the gap, so it has to be strong. Lintels are usually concrete, steel, or occasionally a brick arch, and the material completely changes which drill bit and fixing you need.

FL-02Work out what your lintel is made ofSteel lintels are common from the 1970s onwards and often show as a thin, sometimes painted, strip of galvanised metal just above the window frame. Concrete lintels look like a solid grey band. Tap gently with a knuckle: concrete sounds dull and dense, steel gives a slightly hollow ring. A small fridge magnet stuck to the surface confirms steel.

FL-03Check for cables and pipes before you drillAlarm sensors, curtain pole lights, and blind motors sometimes run wiring along the top of a window opening. Scan the area with a cable and pipe detector first. But a detector reduces risk, it doesn't remove it: it can miss cables that run deep, sit inside metal conduit, or hide behind metal-backed plasterboard, and older or amateur wiring often ignores the usual safe zones completely. If there's any doubt at all, isolate the circuit at the consumer unit before drilling, and turn off the water at the stopcock before cutting into anything that could carry a pipe. Treat the area as if something is there until you've proven otherwise.

FL-04Pick the right drill bit for the materialFor a concrete lintel, use a masonry bit in a hammer drill or SDS drill (a drill that thumps as well as spins, needed for hard material). For a steel lintel, swap to a plain HSS bit (high-speed steel, usually silver, made for metal) and switch the hammer action off completely. Hammering on steel just blunts the bit and makes it skid.

FL-05Drill into a concrete lintelMark your point, then start the drill on a slow speed to make a small dimple so the bit doesn't wander. Increase speed with the hammer action on, keep the drill at 90 degrees to the surface, and let the tool do the work rather than pushing hard. Expect fine, uniform grey dust; if you're pushing so hard the surface starts to crack or crumble, ease off.

FL-06Drill into a steel lintelUse a centre punch (a pointed hand tool you tap with a hammer) to make a small dent so the bit doesn't skate across the metal. Drill slowly with steady, even pressure and no hammer action, adding a drop of cutting oil to stop the bit overheating. You'll know you're through when the resistance suddenly drops and you see a curl of metal shaving instead of dust.

1 bottle · Cutting oil

Buy:ScrewfixB&QToolstationAmazon

FL-07Fit the correct fixing for each materialFor concrete, tap in a wall plug (a plastic sleeve that grips the sides of the hole) sized to match your screw, then drive the screw in until it's snug. For steel, skip the wall plug entirely and use a self-tapping screw, which cuts its own thread directly into the metal, driven in slowly with a screwdriver or low drill speed.

1 each · Wall plug

Buy:ScrewfixB&QToolstationAmazon

1 each · Self-tapping screw

Buy:ScrewfixB&QToolstationAmazon

FL-08Check the fixing is actually solidGive it a firm pull and a side-to-side wiggle; it should not move, creak, or pull loose at all. On concrete, the plug should sit fully seated with the screw head flush. On steel, the screw should feel tight the whole way in, not spin freely at any point. Don't accept a fixing that holds a light load 'for now' - it should feel completely solid before you trust it with anything.

Some links may earn us a small commission at no extra cost to you.

Save this as a project

Back to all guides