Kilcash castle was the home of the cadet branch of the earls of Ormond. They eventually succeeded to the senior earldom in the 16th century. Inevitably houses/castles like Kilcash became unnecessary to the survival of the family and allowed decay.
Just to scale it. The windows in the house part are about ten foot high. And in the 1st shot you can draw the floor line through from the house to the castle giving five floors in the tower. This tower/keep/castle is 300 years younger than the last post. Inside this one you have timber floors instead of the barrel vaulting.
I suspect that the house part was quite a bit bigger. At the time of building the trend in house building was for a renaissance style, so you could probably add another window then a door without a window above it and then as much more of the house again.