Light non-structural fixings in shear - battens, clips, conduit, grounds - and not much else.

In sound mortar and soft brick they develop reasonable resistance to loads along the wall.

Withdrawal resistance is modest in every substrate, so anything pulling straight out is a poor application.

In dense concrete they may not penetrate at all, and in aerated or hollow block they crush through and hold nothing.

The substrate varies enormously within one wall, so results are inconsistent by nature.

Anything structural, overhead or safety-related needs a drilled anchor with a published capacity.

They are hardened far beyond ordinary nail steel so they can penetrate masonry, and hardness brings brittleness.

An ordinary nail bends when it meets resistance; a hardened one resists bending and eventually fractures.

Pieces can break away at speed, which is why eye protection is essential when driving them.

Glancing blows and off-axis hammering are the usual cause, since a bent load path concentrates stress.

Driving straight, with a heavier hammer and fewer firmer blows, reduces the risk.

A nail that has started to bend should be removed rather than straightened.

Usually the mortar joint - it is softer, more consistent and does not split the unit.

Driving into the face of a brick risks splitting it, and a split brick is a visible and permanent defect.

Mortar is softer, so the nail penetrates more predictably.

Weak, perished or unfilled joints hold very little, so the joint must be sound.

In dense engineering brick, neither is easy and a drilled fixing is the sensible route.

In concrete there is no joint to choose, and consistency depends entirely on the aggregate the nail happens to meet.

Not close - edge distance matters as much as it does for drilled anchors, and a nail near an edge splits the unit.

A brittle substrate resists a wedge only while there is material all around it.

Near a free edge, the corner breaks away and the fixing holds nothing while appearing driven.

The same applies close to an existing crack or a previous failed fixing.

Several nails in one mortar joint can crack the joint along its length.

Where the position is fixed and close to an edge, a drilled anchor sized for the edge distance is the correct answer.

Enough to penetrate the substrate properly behind whatever is being fixed - roughly two-thirds of the nail in the masonry as a rule of thumb.

Too short and there is barely any nail in a material that was never going to grip strongly anyway.

Too long and the extra length meets more resistance than the nail can take, and it buckles or snaps.

Thin renders and plaster count as part of what is being fixed rather than as substrate.

The batten or fixture thickness therefore drives the length directly.

If the required length will not drive, the substrate is telling you to drill instead.

With difficulty and usually with damage - they are not intended to come out.

The fluting keys into displaced material, so withdrawal tears the substrate around it.

Levering against a brick face is likely to spall the surface.

Cutting the nail off flush and leaving the shank in place is often the least damaging option.

Because they are hardened, they are also difficult to cut and can shatter under a chisel.

Where a fixing may need to come out, a drilled anchor with a screw is a far better starting point.

Considerably, where the volume justifies it - the drive energy is controlled rather than depending on a hammer swing.

Powder and gas-actuated tools drive hardened pins into concrete and steel with consistent penetration.

That consistency is exactly what hand-driven masonry nails lack.

The pins are a related but distinct product, matched to the tool and the substrate.

These tools are regulated in most markets and require operator training and certification.

For occasional fixings the hammer remains the practical option, with its limitations understood.