Like all monasteries, Daphni was built in order to serve the needs of the convent. This dictated the many additions and repairs during its long history.
The catholicon. Being the most important part of monastic life, the catholicon church is usually
monumental and occupies the centre of the monastery. The Daphni church has an impressive size, complex architectural type and high-quality masonry. It is one of the most important Helladic examples of the composite octagonal type. It has a large cube with a large dome, which, on the inside, steps upon four pairs of supports, both pillars and walljambs. The support pairs form four squinches and eight pendentives bearing the dome. The octagonal type follows Persian and Armenian prototypes, which were diffused to the Greek mainland through Constantinople, where the idea of squinches had been invented and used in the 10th and 11th centuries.
Octagonal churches leave a wide space underneath the dome, which creates a united and uplifting feeling. At Daphni this feeling is further stressed by the light coming from sixteen dome windows. The exterior is an example of stone and brick cloisonne masonry, with pseudo-kufic decoration and simple brick stripes round
the window arches. The sculpted decoration is restricted but well-crafted. The narthex acquired an exonarthex in the 12th century, in the form of an open portico with an upper floor, the abbot’s residence and library. It preserves traces of 12th and 13th century paintings, while the church has post-Byzantine paintings (17th century). The northwest section of the Daphni Monastery catholicon after the exonarthex restoration
(Deltion tis Christianikis Archaeologikis Etaireias, 1962-1963, pl. 4, fig. 3).
The enclosure wall. The monastery was protected by a strong square defensive wall (about 97x97 m). It was 8 m high, with an internal passageway 1.6 m wide, supported by a blind barrel vaulted corridor. It had battlements and four square towers, three of which survive today. The wall was built with conglomerate blocks 1.6 m x 0.4-0.6 m and occasional brick layers.
The main entrance was on the middle of the west side, protected by a tower and side bastions. A second smaller gate, a rare phenomenon for monasteries, was on the east side, and is today used for public access. Convents were miniature castle-towns and the wall was an essential feature, as they were frequently located in isolation, or because they wanted to be kept apart from outside temptations. The fortification of Daphni, close but outside Athens, served both purposes.
Monastic cells. Monk cels were usually situated on the inside of the enclosure wall, in order to economize space and strengthen the wall. They were two and sometimes four-storied complexes, opening to porticos and accommodating the beds and a few niches for the books, clothes and other personal items of the monks. Daphni had cells on the north and west sides. The west complex was not attached but left a narrow corridor before the wall. A third, south, complex with an internal courtyard was built by the Cistercians and then repaired by the Orthodox monks.
Refectory and cooking area. The simple monastic meal was one of the most important moments in the daily life of the convent. Refectories are spacious rectangular areas with an apse on one short side. Monks were seated at long tables and the abbot sat at a special table in the apse. The walls were decorated with
Old and New Testament scenes. At Daphni the refectory is 28.7 m long and is situated north of the catholicon,
with which it shares the same orientation. Both buildings display similar masonry and thus the refectory may be dated to the 11th century.
Monks entered through three double doors on the west side. The room was barrel vaulted and had windows in the long walls. A round building attached to the north of the refectory was probably used for cooking. It features a central hearth and chimney, as well as niches for utensils.
The baths. Monastic bath complexes are a rare feature suggesting prosperity. They were constructed accoding to the Roman tradition. They had four areas, namely a dressing room, two hot rooms and one room with water pools, either cold or hot. The water was heated with air produced by fire under the floor and distributed with clay pipes. Only the foundations of the baths are preserved at Daphni.
The cistern. An underground rectangular cistern 13.3x4.95 m has been traced underneath the 16th century cells. It has a capacity of 300 cubic meters. It had two barrel vaulted aisles and circular openings on the roof
for water collection. It is similar to cisterns at Hosios Lukas and S. Sophia at Mystras.
The rectangular room. A rectangular room, 23x6.5 m with Middle Byzantine masonry but unknown function lies south of the catholicon.
The sepulchral church of St Nikolaos. In the forrest east of the monastery lies the deserted chapel of St Nikolaos. It is contemporary with the catholicon and may have been the cemetery church. It is a small barrel vaulted basilica with stone and brick cloisonne masonry.
A mausolium crypt lies underneath the church.