A funny thing about Sisk, the largest construction company in Ireland, is its longevity. It was founded in 1859 and has been passed through five generations of the Sisk family. In any industry, passing a business down through five generations is hard. Lots can go wrong in 160 years, on the family side as well as the business side. Sisk is 96 per cent owned by three Sisk brothers and their families – JP, Owen and Richard. They succeed their fathers George, Henry and John, who took over the business in the 1960s. If it’s hard to keep a family…