Why Scottish Castles Look the Way They Do

Every castle you visit in Scotland is a compromise between three things: the stone that lay nearest to hand, the weapons that might be used against it, and the money and ambition of whoever was building. Once you hold that idea in mind, the details begin to make sense. A tower house in Aberdeenshire built from hard granite looks quite different from a border fortress dressed in sandstone, yet both were designed to keep people out. Ask yourself what the builder was afraid of. If the answer is reivers on horseback, you will find thick walls and a single guarded entrance. If the answer is artillery, you will find low, wide walls and gun loops. If the answer is very little, you will find generous windows and comfortable rooms.

Reading the Walls

Start with the masonry. Scottish masons worked with whatever was quarried closest, so you will see rubble walling almost everywhere: irregular stones bedded in lime mortar, often finished with a coat of harling, a lime-based render that has usually weathered away. Where a wall was meant to impress, masons squared and dressed the stone instead. The neat ashlar blocks at the corners of a building, properly called quoins, are a good clue to a high-status build.

Thickness tells you a great deal about date. Walls of 1.5 metres or more generally point to a medieval structure raised to resist battering, arrows and small arms. Look too for a batter, the slight outward slope at the base of a wall, which sheds missiles and strengthens the footing. Walls of half that thickness are usually later, when the threat had changed and comfort mattered more.

• Rubble with harl: local, ordinary, defensive.
• Dressed ashlar and quoins: expensive, decorative, often later.
• A sloping batter: medieval, structural, practical.

Keeps, Tower Houses and the Z-Plan

The earliest stone castles in Scotland were often rectangular keeps, compact and brutal, with a vaulted basement, a hall above and a parapet walk on top. From the fourteenth century onwards, the tower house became the standard form: a tall, narrow block, usually four or five storeys high, with a turnpike stair squeezed into one corner.

Clever builders then began to experiment with the plan. The L-plan placed a wing at right angles to the main block, so defenders could fire along two faces. The Z-plan is the most distinctive of all: two towers set diagonally at opposite corners, allowing flanking fire along every wall. Examples such as Craigievar and Crathes show how easily these defensive shapes were adapted into comfortable homes.

Windows, Gunloops and Doorways

Openings are the quickest way to date a building. Early castles have few windows and they are narrow slits, splayed wide on the inside so a defender could aim through them. Look for gunloops: small openings shaped like a keyhole or a cross, cut through the wall to let a handgun or arquebus cover the approach. Later, when glass grew cheaper and peace more common, windows widened, gained mullions and transoms, and eventually became the familiar sash windows of the eighteenth century.

Entrances deserve a close look. A first-floor doorway reached by an external timber stair is a classic Scottish arrangement, allowing the stair to be pulled up or burned away in a raid. The door itself often sat behind an iron yett, a heavy grille of interlocking bars, and a drawbar socket cut into the stonework is still visible in many ruined walls.

Corbelling, Bartizans and Crow-Stepped Gables

Half the pleasure of Scottish castle spotting lies in the roofline. Where a turret projects from a wall, it usually rests on courses of corbelling, each stone stepping out further than the one below. These rounded corner turrets, called bartizans, gave defenders a view along the wall foot. Some are open rounds with a parapet; others are roofed and slate-hung.

Then look at the gables. The crow-stepped gable, with its stair-like edge, is unmistakably Scottish. It hides the skew, the sloping stone that caps the gable wall, and it allowed a roof of stone slabs rather than thatch or turf. Slate gradually replaced heavier materials, but the crow steps remained as a mark of status long after they stopped being practical.

Barmkins, Gatehouses and Later Rebuilds

Finally, step back and take in the whole site. Many castles were surrounded by a barmkin, a walled courtyard that sheltered cattle, stores and lesser buildings during a raid. Inside you will often find the foundations of a hall, a kitchen and a brewhouse, arranged around a small close.

Remember, too, that almost no castle is a single moment in time. Victorian owners added grand wings, sash windows and mock battlements to buildings that had once been grim and draughty. Learn to spot the joins, the change in stone, the straight vertical line where one phase meets another, and you will read the whole story of a building in a single walk around it. Take your time, keep looking up, and the walls will start to talk.