Share prices in Irish building materials group Kingspan dropped sharply after the company disappointed investors by announcing its 2005 earnings would only be “in line with current market expectations”.

Shares fell by up to 4.9% following Kingspan’s trading update, published in advance of its preliminary results which will be released on March 6.

However, the company, which owns the Century timber frame house business and TEK structurally insulated panel system, said operating profits and earnings growth would be significantly ahead of 2004.

Kingspan’s spend on acquisitions during 2005 was €140m, including €98m on buying Century.

The company said: “These acquisitions should enable the group to benefit from changes in construction methods from more traditional solutions. The group’s insulated panel and board businesses also continue to benefit from shifting construction practices.”

Kingspan reported weaker conditions in the construction sector and lower economic growth estimates generally for the UK. But it does not expect the factors to significantly impact its overall business.