Let’s talk about castle foundations. Isn’t it incredible how these heavy buildings haven’t sunk into the ground after almost thousands of years? The next question that comes to mind is what kind of foundations are hidden beneath a castle, or do the castles actually have foundations?
Yes, castles have foundations. Most of the Castles have sturdy foundations in the form of natural bedrock on elevated locations or high hills. When such an option wasn’t available, they used foundations similar to the modern-day system, when a wide trench is dug and filled with gravel to provide a stable base for the castle.
One common feature about castle builders in the medieval era is that they focused on readily available building materials. The same thing applies to foundations.
Most castle builders dug deep into the ground, located the natural bedrock, and built upward.
In this article, you will learn about the various foundation methods used in the medieval era regarding castles.
How were Castle foundations built?
Since ancestors mostly built castles on hills and elevated areas, all the builders had to do was locate the bedrock and then attach the main walls of the castle to it.
As such, the buildings were firm to the ground.
When that method did not work (due to the area’s topography), a wide trench is often dug in the desired layout, and then gravel is mixed with binding materials such as cement, and then the main buildings are built on it.
This latter method is more recent. However, generally before now, the builder’s first task was to find a suitable ground that could hold a castle, but in recent times with increasing construction techniques, a castle can be built just about anywhere, provided the suitable building tools/ materials are available.
Materials used in building castle foundations
People built Castles in England and all over the world from diverse materials. Such as:
1. Stone foundation
Stone castles began to evolve in the 1100s. They were favoured for their invulnerability, as assault weapons couldn’t easily penetrate or pass through the wall.
These stone castles had sturdy and stony foundations (Note that even some earthen castles had stone foundations too).
For stone castles, the stones used for the main buildings were usually the same as the stones used for the foundations, except that the foundation stones were often undressed and buried underneath the ground.
Are you wondering what kind of stone they used? Unfortunately, there are no hard or fast rules about stones used for building castles.
Medieval builders used stones that were available or around them or that could be procured.
For example, The Carlisle castle in England was built out of locally sourced grey and red sandstone. In contrast, some castles were made of flint, sea pebbles and chalk, rock, etc.
2. Gravel foundation
More contemporary foundation methods for castles included the use of gravel.
Gravel was used at the foundation level sometimes, while at other times, the gravels would be mixed with whichever binding materials were readily available at the time.
Gravel foundations have proven reliable and are still used for buildings up to date.
3. Brick foundations
Yes, this sounds oddly recent, but some castles indeed had brick foundations – especially brick castles.
A typical example is the Kenilworth castle, built in bricks in the early 13th century.
4. Timber Foundations
Masons originally built many old castles with wood because it was one of the most reliable and most available building materials.
Timber was obtained from nearby forests and used to build the castles. Many of those castles had their foundations laid with wood.
As time went on, castle builders encountered the challenge of decaying timber and weakening this structure, which explains why most of the wooden structures were converted to stone castles in more recent times.
In Lithuania, there are over 1000 sites of hill forts that used to have wooden castles on them.
5. Earthen Foundations:
Earthen foundations can be commonly seen in Motte and Bailey’s castles of earlier times.
These castles were primarily built around hills. Earth and clay were usually moulded from and around the hills, using the hill as a natural foundation.
The Motte and Bailey castles were favoured for their defensive designs and were propagated or improved by the Normans.
Why Motte and Bailey castles?
They were easy to build and could be completed in few weeks. Even with an impending attack, lords with sufficient manpower could build a suitable and secured motte and bailey castle.
These castles had three major parts;
• The Motte is a raised mound of earth where the main building (keep) is located. It could be found in the middle of the bailey or outside but always with direct access to it.
• The Bailey is mostly an enclosed courtyard usually housing the castle. A wooden fence surrounds it called a palisade and usually is circled by a moat with one or two drawbridge going over the moat for access.
• The Keep is the last resort in a Norman castle, which is also the main building where kings and nobles spend most o their time.
Motte and bailey castles were susceptible to fire – this is another main reason they were replaced with stone castles later on.
Iron & Lead Foundation
Imagine a castle whose foundation is laid in iron! Some historians have maintained that in the 9th century, iron and lead were used for foundations.
Many also opine that engineers used them for building pillars and other building parts. Although there is no physical evidence of such castles today, iron could probably have served as a foundation since they are firm and reliable. Thus, people in medieval times used what was solid and available.
Did castles have basements?
Most of the large medieval castles have basements that the owners used for different purposes like storages, dungeons, ice houses, or keeping many people during a siege.
If you made it that far you are probably a castle enthusiast, same as us.
In this case, there are plenty of questions answered in our blog section, like;
What Is The Largest Castle In Ireland?
What is Inside a Medieval Castle?
How Much did it Cost to Build a Castle in the Middle Ages?
How Much Does it Cost to Maintain a Castle?
What’s the Difference Between a Palace and a Castle?
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