The construction sector here made a strong start to the year, posting faster increases in activity, new orders and employment, as well as seeing confidence improve again.
But input costs rose to their highest extent in 11 years.
That's according to the Ulster Bank Construction Purchasing Managers' Index.
It rose to 61.4 in January, from 58 in December.
The latest reading was the fastest since May of last year.
"The latest results of the Ulster Bank Construction PMI survey paint a very encouraging picture of early-year activity trends in Irish construction," said Simon Barry, chief economist Republic of Ireland at Ulster Bank.
"There was a particularly notable acceleration in commercial activity, making it the fastest-growing sector last month.
"However, the improvement was broadly based, with the housing PMI also rising to an eight-month high, consistent with ongoing very rapid activity growth."
Activity has risen continuously in the construction sector since September 2013, with experts linking the expansion to the securing of new contracts. Mr Barry said construction firms are looking to the year ahead with high levels of confidence, buoyed by further improvements in the economy.
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