Guedelon Castle

A unique and wonderful tourist attraction, Guedelon Castle is a project to construct a medieval castle using medieval construction techniques. Much has been learned in the process with the public visiting and observing the progress.

Rough hewn wood is stronger and lasts longer that modern sawed wood. Long pieces are transported suspended between two sets of wheels.

Nails were an expensive luxury in the Middle Ages, so wood was joined and pinned.

For roofing, wood could be used, but for a fortification a flammable material is dangerous. Tiles are a better solution. Shaped with a lip, the tile is secure resting on a wooden slat on the roof.

Baskets are needed to transport clay and material for mortar. Clay is worked into rectangular shape with a lip to rest on roof slats. The tiles are then placed on wooden left out to dry for a few days.

Fired in the kiln, the tiles are now ready for use. Thousands of tiles are needed to finish the castle.

Castle construction required an enormous amount of stone. Experienced quarrymen could look at rock and see the weaker layers and split it accordingly, creating pieces of approximately equal size. If the quarry site was far from the construction site, transportation costs could be great.

Rough stone or rubble from the quarry could be used for the interior of walls. Stone for the outer walls required much more work. After quarrying, the stone would be shaped to the proper size according to its place on the wall. When construction first began, the workers were careful to create smooth surfaces. Progress was slow, however, so more recently the workers have been less careful about producing smooth stones for the walls.

Other stones must fit strict patterns and therefore require careful shaping. This is among the most skilled labor involved in building the castle.

Leverage is used to lift the stones onto carts. Stones can then be transported by horse pulled cart or for smaller pieces by human pulled carts. A small treadmill can be seen below the castle walls. A double drummed treadmill winch can be seen atop the walls, powering a crane.

Small pieces can be winched to the top of the walls by a small hand powered device. Large stones requires the treadmill lifting equipment.


The treadmill can be worked by walking inside of it, or for lighter items turning it by hand. The rotation winds or unwinds a rope around a spindle, either lifting via the crane or lowering an item. Devices like this were common until industrialization in the 1800s. The castle feature projecting outward in the photo at right is the garderobe, or latrine.

For safety reasons the scaffolding is not a 100% medieval style, but the principles are the same. The lower levels are simple enough, but as the wall grows higher, poles are stuck into gaps in the stonework, "pigeon holes", to support the platforms. The weight of the treadway powered crane justifies using several levels of these pigeon holes. The stonework must be planned with these pigeon holes in mind. The holes are filled after the wall has progressed further up.

As the wall progresses higher there is concern with keeping the masonry level. In the picture at right you can see three bands with neater, more orderly masonry, each with three courses, or vertical layers, of stonework. These leveling courses are more carefully done to keep the building on track.

The inside of the walls was made of unfinished rubble. The photo at left is from Chateau Gaillard, where you can see the inner rubble as the outer finished stone has been salvaged after the castle became obsolete. The panorama at right shows construction of a tower at Guedelon with the curtain walls under construction in the foreground. The basket at right has been used to hold mortar. Mortar used inside the walls is a course variety which allows the stones to settle as the mortar dries over several hundred years. By changing the content of the mortar - amounts of lime and water and the grade of sand.

On the inside corners note the white limestone which is more smoothly finished being a softer rock. As the tower is built higher, an arched ceiling will be built.

A centring, the device in the photo above, is designed to brace the stones as they are laid to become the arch ceiling. The photo above right shows the whole wooden assembly involved with building an arch. When the arch is complete, the wooden blocks supporting it are knocked away, and the arch stands on its own supporting weight. The mortar used in building arches is a flexible type. Although it appears stationary, masonry moves a small amount.

The arched ceiling we have just seen is in the great tower behind the treadmill crane. This tower was designed larger and stronger than the others and could be used like a keep for a last ditch defense. A cutaway of the wall at right shows its rubble interior. Just down the wall is the tower construction that we have seen. Now, let's go to the great hall construction, which is nearing completion.

This is the lower floor of the great hall. The beams above us will support, or will support, the flooring of the level above us. For now it is incomplete, so in the photo above we can even see the undersides of the roofing tiles. You can also see the section near the fireplace where flooring has been installed and a place for visitors to walk on the right side.

The photo at right shows a sliding wooden piece recessed into the wall. It can be pulled out to bar a door.


This is the upper floor. The wood supporting the ceiling was difficult to bring into position as a treadmill crane was thought too dangerous for such heavy loads. Above you can see the wooden slats that the tiles rest upon. At the fireplace, dry dirt is put atop the wooden floor then covered with tiles in order to keep the building from catching on fire.

Castle construction will construction will continue for some years then other projects may be in the offing. Americans who are not planning to travel to Europe can instead go to Arkansas where a castle inspired by Guedelon is being built.

Back to John's Military History Tour of Europe