This of course, then leads to other things your castle needs, the Midden (Located under where the garderobe was located) with access from the outside so the feces could be easily removed.
The term garderobe describes a place where clothes are stored (wardrobe is a related term), but may also be used for places where other items are stored, or euphemistically for historical toilets.
In European public places, a garderobe denotes the cloakroom, but it may also be an alcove or an armoire. In Danish, Dutch, German, and Spanish garderobe can mean a cloakroom. In Latvian it means checkroom.
In its euphemistic meanings, a garderobe is either a close stool or a medieval or Renaissance lavatory or toilet. In a medieval castle or other building, a garderobe usually was a simple hole discharging to the outside. Such toilets were often placed inside a small chamber, leading by association to the use of the term garderobe to describe them. Depending on the structure of the building, garderobes could lead to cess pits or moats. Many can still be seen in Norman and medieval castles and fortifications. They became obsolete with the introduction of indoor plumbing.
A description of the garderobe at Donegal castle indicates that during the time when the castle garderobe was in use it was believed that ammonia was a disinfectant and that visitor's coats and cloaks were kept in the garderobe. The construction of garderobes was not limited to Britain and Ireland; they were also common in medieval castles on the continent. An example is Bürresheim Castle in Germany, where three garderobes are still visible today.
According to the medieval architecture scholar, Frank Bottomley, garderobes were:
Properly, not a latrine or privy but a small room or large cupboard, usually adjoining the chamber or solar and providing safe-keeping for valuable clothes and other possessions of price: cloth, jewels, spices, plate and money.
When I map castles, the Solar was often located near the top of a castle's tower(s) with large windows to all sides to accommodate the lords & ladies.
The solar was a room in many English and French medieval manor houses, great houses and castles. In such houses, the main room was known as the Great Hall, in which all parts of the household would eat and live, with those of highest status being at the end, often on a raised dais, and those of lesser status further down the hall. But a need was felt for more privacy to be enjoyed by the head of the household, and, especially, by the senior women of the household. The solar was a room for their particular benefit, in which they could be alone (or sole) and away from the hustle, bustle, noise and smells (including cooking smells) of the Great Hall.
The solar was generally smaller than the Great Hall, because it was not expected to accommodate so many people, but it was a room of comfort and status, and usually included a fireplace and often decorative woodwork or tapestries/wall hangings.
In manor houses of western France, the solar was sometimes a separate tower or pavilion, away from the ground-floor hall and upper hall (great hall) to provide more privacy to the feudal lord and his family.
The etymology of solar is often mistaken for having to do with the sun but this is not so. This misconstrual may result from the common usage of the solar; embroidery, reading, writing, and other generally solitary activities. These activities would need good sunlight, and it is true that most solars were built facing south to take maximum advantage of daylight hours, but that characteristic was neither required nor the source of the name. The source of the word may be related to the French word for 'alone': seul(e), pronounced 'seul','sl'. The name fell out of use after the sixteenth century and its later equivalent was the drawing room.