Consisting of an irregular outer wall from the 13th Century, made with limestone rubble, varying between 1.5 and 2 metres in thickness, at a height of up to 8½ metres, reinforced with flat-faced and rounded buttresses.
The chateau of Irchonwelz is characterised by its original double entrance with a remarkably preserved doorway in well squared-off stonework.
Built into the corner of the outer wall you can see the 2-storey fortified living quarters dating from at least the 16th Century and largely remodelled in the 18th Century. Built on to the North face and integrated into the original gateway, there is a central building from the beginning of the 17th Century, altered in the 18th century, losing its top storey in the 19th. A doorway for barrows cut through in the 19th Century,formed from a string of freestone uprightsand a lowered arch of rubble. Traditionally Irchonwelz was held to be a domain or seigniory of the lords of Silly-Trazegnies, excluded from the sale of the domain of Ath to the Count of Hainault.
Some other sources do not support this view because the presence of the Trazegnies only dates from the first quarter of the 18th Century, wrongly categorised as a fortified house Irchonwelz appears in medieval records (1410) as a stronghold, a structure somewhere between a castle and a lord of the manor"s redidence. This description reflects the earlier importance of what appears as the survival at the beginning of the 13th Century from the great 12th Century castles of Hainault.
