How Tall Are Castle Walls? Solved!

The primary function of a castle wall is protection. Not only must castle walls be sturdy enough to repel projectiles, but they must also be tall enough to make scaling them a difficult objective. Any visitor to a castle will tell you how imposing the looming walls feel as you stand at their base. Therefore, you might wonder how tall are castle walls?

The average height for castle walls is 30 feet. Castle walls evolved with the siege weapons they faced. Medieval castle walls need to be taller to protect against projectiles that could be hurled further and higher. The arrival of the concentric castle design saw two curtain walls, the inner wall taller than the outer wall.

The height of a castle wall varied from castle to castle, with the average being 30 feet. In this article, I shall look at the evolution of the castle wall and why it was so important in the defense of a castle. I will also look at examples of castles that opted to build castle walls higher than the average.

Harlech Castle in Wales
Harlech Castle in Wales, whose walls are around 39 feet high

The Role of the Castle Wall

The castle wall was the crucial first line of defense against any attacking force. Castles were often built to impose a monarch’s or lord’s rule over the local area. They were a symbol of power, used to subjugate a local population and deter future rebellion.

However, they were also primarily defensive structures.

They were designed to withstand attack and subsequent siege. The castle or curtain wall was critical as the first line of defense. Once penetrated, the inner castle was likely to fall rather rapidly.

The walls needed to be sufficiently sturdy to withstand catapulted projectiles. They also needed to be tall enough to make scaling a tough prospect.

They were the boundary walls behind which were the buildings required for everyday castle life. The design of the wall was arguably the most crucial element of castle architecture.

What Is the Average Height of Castle Walls?

On average, castle walls were built to a height of at least 30 feet, although they could be built much higher. The walls at Framlingham Castle in Suffolk are 44 feet tall, while those at Knaresborough Castle in North Yorkshire were 40 feet high.

Stone walls required solid foundations, and the taller the wall the stronger the foundations required. The base of a wall was its most vulnerable point, and this vulnerability could increase with the height of a wall.

Towers and moats helped to protect the base of the wall which was often a blind spot for the castle defenders manning the battlements above.

Therefore, it was about finding the balance between practicality and maximizing defensive capabilities. Stone walls cost money too, and every additional foot delved deeper into the purse of whoever was paying the bill.

This often came back to the locals who ended up paying higher taxes.

A castle wall 30 feet in height was still a significant obstacle for a besieging force. If you could not scale the walls, you needed to bludgeon your way through using a trebuchet.

Undermining the walls to make them topple was another tactic. If all else failed then it became a game of patience, waiting for the castle to run out of food and drink.

The following table provides examples of the heights of several castle walls:

CastleLocationHeight of wall
PortchesterHampshire, England20 ft
BerwickNorthumberland, England30 ft
Chepstow TownMonmouthshire, Wales30 ft
Conwy CastleConwy, Wales30 ft
BeaumarisAnglesey, Wales35 ft
ConisbroughSouth Yorkshire, England35 ft
KnaresboroughNorth Yorkshire, England40 ft
FramlinghamSuffolk44 ft
Conwy Castle with walls around 30 feet high
The imposing Conwy Castle has walls that are 30 feet high

Curtain Walls Were Nothing New

Of course, defensive walls were not invented by medieval castle designers. We can see the evidence in the hill forts dating back to the bronze age.

These forts were sites built on higher land. They used earthen mounds, ditches or wooden palisades to enclose the site (source), usually following the contours of the land.

Ancient Egypt and Rome are further examples of civilizations that saw the benefits of curtain walls. These could be around forts or whole cities, offering protection to those within when aggressors were knocking at the door.

When the Normans built castles across the British Isles to enforce their rule, sturdy castle walls were a must.

The Normans wanted to promote their power and subjugate the locals to the new reality of Norman rule. However, they also needed somewhere to retreat behind in time of rebellion, where they could await relief from a besieging force.

From Wood to Stone

Early medieval castles built their protective walls using timber. This posed the problem of rotting timber in a damp British climate, and therefore the need to frequently replace sections of the wall.

This was inconvenient, potentially pricey, and not ideal if it occurred at the same time as an invading force turned up who spied a weak spot.

There was also the small matter that timber walls were vulnerable to fire. Hence, over time, stone became the go-to material for castle builders.

Stone was stronger, tougher to penetrate with projectiles, and less susceptible to fire. Given the choice of hiding behind a wooden defensive wall or a stone one, there was only one winner.

Stone brought its own challenges. The cost was one, and castles became an indicator of wealth. Yet, heavy stone walls built to 30 feet were apt for subsidence if not built with due care.

Therefore, castle wall design needed to adapt too to build walls that would last the test of time as well as all that a besieging army could throw at it.

The Main Elements of Building a Castle Wall

Once you have found the preferred location for your castle, your chief architect will be taking note of the ground. 30 feet walls made of stone required strong foundations to avoid subsidence and potential collapse.

Ideally, you will dig down to the bedrock, which once leveled out will provide the solid foundations required for the walls.

Unfortunately, life is not always perfect. If you did not hit a suitable layer of bedrock then you needed your workforce to build a suitably wide ditch. This would be filled in with rubble, which could then be compacted and leveled out as you would with bedrock foundations.

Once the foundations were in place the task of building the walls could begin. Building walls 30 feet or higher needed a fair amount of wooden scaffolding consisting of timber poles tied together using rope.

It may not pass today’s health and safety rules, but building regulations were not top of the considerations at this time.

As the height of the walls grew, a system of pulleys and hoists allowed for the necessary materials to be lifted to where they were needed. The stone was quarried as locally as possible. It was then cemented into place using mortar made from kiln-baked lime, and mixed with sand and water.

Castle walls may also flare out at the base. This helped to spread the load of the additional weight required to build higher stone walls.

Adding the Battlements

Once the castle walls reached their designated height the stone is leveled off. This allowed the design to include additional defensive features. These are centered around the battlements which run along the walls between each connecting tower.

Central to the battlements is the crenelated parapet, which has two main features:

  • Merlons – upright extensions of the castle wall, offering a castle defender protection from incoming arrows and crossbow bolts. These sections tended to be at least shoulder height.
  • Crenels – the gaps between the merlons where a castle defender could keep a lookout or fire arrows down at an attacking force. They were spaced out at regular intervals along the parapet.

Opting for Higher Than Average Castle Walls

While castle walls average out at 30 feet tall, there was no rule to say you could not build them higher if so desired. If you had the financial means and the foundations to support them, you could build taller walls to loom over the surrounding country.

Castles were statement buildings. They exuded the power and wealth of their owners. Taller castle walls magnified the imposing nature of this stone ‘beast’. The following are two examples of castles whose walls were at least 10 feet above the average height.

1. Knaresborough Castle

The stone walls at Knaresborough Castle were built to a height of 40 feet.

The castle sits high up on a rocky outcrop in North Yorkshire in England and was a favorite of medieval monarchs. As well as using Knaresborough as his base in the north, King John was particularly fond of its hunting grounds.

However, it was Edward I who rebuilt the castle we see today, including its taller-than-average curtain walls. The castle was important to Edward, the Hammer of the Scots, in his campaigns north of the border. His son Edward II completed the construction during the early part of the 14th century.

Knaresborough is a good example of how advances in weaponry can outpace defensive fortification design. The arrival of more powerful cannons meant tall and thick castle walls could not offer the protection they once did.

In 1644, the Royalist forces holding Knaresborough castle surrendered after the Parliamentary cannons breached part of the curtain wall (source).

Unfortunately for those of us who enjoy visiting castles, most of the curtain wall was taken down four years later. This was to prevent any future use of the castle by the Royalists. However, the grand stone King’s Tower remained and was used as a courthouse and prison.

2. Framlingham Castle

Framlingham upped the ante further by building its castle walls to a height of 44 feet.

These impressive curtain walls connected by 13 towers encircle an inner residence with a rich history. The height and strength of the defensive walls were such that it was felt a stone keep was not required.

Like many castles, the original Norman structure was built from wood. Located in Suffolk, the castle walls that remain today were built in the early part of the thirteenth century.

The original castle was destroyed when its owner, Hugh Bigod, 1st Earl of Norfolk, rebelled against King Henry II in 1273.

Framlingham became center stage in England’s historic royal dramas during the 16th century. It was at Framlingham Castle that Mary I was proclaimed Queen after the death of young Edward VI.

The Duke of Northumberland tried to have his daughter-in-law Lady Jane Grey, a protestant like Edward, proclaimed Queen.

However, the Catholic Mary was determined to claim her right as the legal heir to the throne. She took cover behind the huge walls at Framlingham Castle, a property that formed part of her East Anglian estates. Here she gathered her supporters and it soon became clear that Northumberland’s cause was a lost one.

This video illustrates the sheer scale of Framlingham Castle’s towering walls.

Ongoing Castle Design

Castle designers needed to keep updating their designs to offset advances in siege weaponry. They came up with the concentric castle, seen by many as the peak of medieval castle design. Now you did not have just one castle wall to build, but two.

The inner wall was taller than the outer wall to allow archers to fire over the heads of defenders on the lower wall. As the outer wall needed to average at least 30 feet to act as an effective first line of defense, the taller inner wall could be up to 40 feet in height.

A classic example of a concentric design is Beaumaris Castle on the island of Anglesey in Wales. Designed by the renowned castle builder Master James of St George for Edward I, the taller inner wall was constructed to a height of 35 feet.

The space between the two castle walls was called the ‘death hole’. As the name implies, this is not a spot where a besieging soldier wants to get trapped as you were open to fire from all sides. This was not likely to end well.

However, as we have seen with Knaresborough, the advent of ever more powerful cannons spelled the end for castles as effective defensive military fortifications. However tall and thick you built the walls, the cannons could now bring them down.