The castle itself is typical of the style for that period although the larger windows were added at a later stage. The main oak door was protected by an outer metal 'drawbridge style' door which was pivoted at the base. Inside, the hall is small and was easily defended; above is a rectangular opening called a murder hole, which certainly gave advantage to the defenders. There is a circular stone staircase in the north east corner, which leads directly to all the chambers and eventually to the parapets. To the right of the entrance hall is the Guardroom.
The small chambers in the castle are all located at the north end. Halfway up the staircase a narrow passage leads to the Garderobe and this provided the only toilet facilities within the castle. The Bed Chamber has a fine vaulted ceiling. Unfortunately the original collapsed but the replacement has been reconstructed using medieval building techniques. To construct the vault two enormous wickerwork mats were woven in situ and placed on temporary timber formwork. The stone vault was constructed directly on top of this and when the formwork was eventually removed the wickerwork remained leaving an interesting woven pattern. To make the plaster, the lime and sand were mixed with coarse animal hair, which helped stop it from cracking as it dried out. No animal hair was used in the final layer. Most of the windows had pivoted timber shutters.
The most important chamber is the Great Hall and this is situated at the uppermost level. It has two large six-light windows and only at this position would it have been safe enough to have such large openings. The finest fireplace is located here and this room would have been the centre of activity in the castle. At one end separated by an oak partition is a kitchen and above this, a minstrels' gallery. The whole space is covered by a reconstructed oak roof using adzed timber which is pegged together with oak dowels - no nails were used.
The parapets on the castle are conjectural and are based on those remaining on the McCarthy castle at Ballycarbery near Cahirciveen. The chimney is based entirely on the original, which had to be taken down for structural reasons.
Bartizans are situated at the north west and south east corners of the castle - these are overhanging turrets from which missiles etc. could be dropped with ease on the attacking enemy below. They have a range of musket loops, as this was the ideal place to locate musketeers. Over the entrance door is a very unusual feature for an Irish castle - an oak door hinged from projected stone brackets, which allowed soldiers to defend the entrance door from above.