Drilling into a concrete garage wall

Which concrete you are drilling

Concrete in a garage comes in three forms and they drill differently. Dense concrete block is the grey blockwork of most brick-and-block garages: hard, but drillable with an ordinary hammer drill. Poured or in-situ concrete, whether a lintel, a retaining wall, the slab or a column, is harder still, denser, and more likely to contain reinforcing steel. Precast sectional panels are thin and reinforced, and are covered separately below because they need different handling.

Aerated block is a concrete product as well, and it is the exception to everything in this guide. It drills on rotary only, with no hammer action, and takes its own fixings. If the test hole throws pale dust and the bit goes in with no effort, stop reading this guide and read the one on breeze block instead. Hammer drilling aerated block wrecks the hole before the fixing has gone in.

Hammer drill, SDS rotary hammer, or rotary only

The names get muddled. A hammer drill is an ordinary drill with a hammer setting: the chuck vibrates rapidly along its axis as it turns. It is effective in brick and dense block, slow in real concrete, and hard on the bit. An SDS rotary hammer is a different tool with a piston mechanism that delivers far harder blows, and it takes bits with a slotted SDS shank that slide in the chuck. In poured concrete it is not a luxury.

For a garage wall of dense block and a handful of hooks, a decent hammer drill does the job and most people already own one. For a run of frame fixings into a concrete lintel, or a whole tool wall on a poured concrete wall, borrowing or hiring an SDS for a morning turns a miserable afternoon into twenty minutes. The tool choice is about the material and the number of holes, not about looking serious.

Bit size, depth and dust

Use a carbide-tipped masonry bit, sharp, at the diameter printed on the fixing packet. Not the nearest one you own. A worn bit drills slowly, wanders, and makes an oversized hole from the heat and the wobble; a worn SDS bit is cheap to replace and worth replacing. Start the hole on rotary only for a few turns to stop the tip skating, then switch to hammer once it has bitten.

Depth: a little deeper than the fixing is long, so dust in the bottom of the hole does not stop the fixing seating fully. Mark the depth on the bit with tape or set the drill's depth stop. Then get the dust out. Pull the bit in and out a few times as you drill, and blow or vacuum the hole before the fixing goes in. A hole full of dust is a hole the plug slides in rather than grips.

That dust is worth taking seriously. Concrete and block dust contains fine silica, and breathing it in a shut garage is a genuine health issue rather than a nuisance. Open the door, wear a proper dust mask rather than a paper one, wear eye protection, and vacuum as you go rather than sweeping it into the air afterwards. A drill-mounted dust catcher or a helper with a vacuum nozzle at the hole both work.

1. 1Mark and checkMark the hole, then check the wall for cables and pipes with a detector, especially near sockets, switches and the consumer unit.
2. 2Start on rotaryA few turns without hammer action so the tip bites where you marked instead of skating across the surface.
3. 3Switch to hammerSteady pressure, square to the wall, and let the tool do the work. Leaning harder does not drill faster; it blunts the bit.
4. 4Clear as you goWithdraw the bit every so often to pull the dust out of the hole rather than packing it into the bottom.
5. 5Reach depth and clean outStop at the tape or depth stop, then blow or vacuum the hole until nothing more comes out.
6. 6Fit the fixingTap the plug or anchor flush, offer up the item, and drive the screw home to the fixing packet's instructions.

Reinforcement, cables and edges

If the bit suddenly stops making progress and starts squealing, you have hit steel: reinforcing bar in poured concrete, mesh in a precast panel, or occasionally a metal wall tie. Do not force it. A masonry bit will not drill rebar, and leaning on it blunts the bit and can snap it. Withdraw, move the hole along a little, and fill the abandoned one.

Before any hole in an integral garage, think about what is in the wall. Cables run to the consumer unit, to the garage lighting and sockets, and through to the house; pipes serve boilers, outside taps and radiators. Cables are usually run vertically or horizontally from the socket or switch they serve, so avoid drilling in line with an accessory. A cable and pipe detector is cheap insurance, and a wall you cannot account for is a wall to drill carefully and shallowly.

Keep fixings well in from the edge of a block, a lintel or a panel. Hammer action near an edge spalls the concrete away and the fixing has nothing to expand against. If an item's holes force you close to an edge, move the item or use a batten to relocate the fixings somewhere with solid material around them. The same goes for mortar joints in blockwork: the joint is weaker than the block, and a plug in a joint is a plug in the wrong place.

Precast concrete sectional panels

The concrete sectional garage, with its ribbed panels bolted together under a corrugated or panel roof, is common enough that it needs its own paragraph. The panels are thin, cast with steel reinforcement, and there is no depth of sound concrete for a fixing to reach into. Hammer action near an edge cracks them. A hole through the panel is a hole to the outside. An expansion anchor has nothing to expand against and can burst the back face.

Light things, such as a clock, a small rail or a single hook, can go into the thicker ribs with short fixings, rotary or gentle hammer, and a careful eye for steel. Anything with real weight on it should not hang on a sectional panel at all. Stand a freestanding unit against the wall instead, and keep the drill for the things that weigh nothing.