SIG, which operates across the UK, Ireland and Europe, said underlying pre-tax profit fell to 26.9 million pounds in the six months ended June 30, from 34.4 million pounds, a year ago.
"The first half did not provide the trading backdrop we wanted, with significant challenges in the UK market as a result of the poor weather in the early months of the year and continuing macro uncertainty," Chief Executive Officer Meinie Oldersma said.
Revenue rose 1 percent to 1.36 billion pounds in the first half from a year earlier.
SIG, which supplies insulation and roofing products, said underlying operating profit from the UK and Ireland fell to 14.2 million pounds from 637.8 million pounds a year earlier.
"The first-half results were both disappointing and encouraging. The UK result, in part caused by the poor weather but also weak underlying market conditions, left group PBT (profit before tax) down 7% on an underlying basis. European activity was much better," Peel Hunt analysts said.
SIG maintained its full-year expectations, amid ongoing challenges in the UK construction sector as growth in British construction activity slowed in August after reaching a two-year high the month before.
(This version of the story corrects year-ago figure to 23.7 million pounds in paragraph five).
(Reporting by Noor Zainab Hussain and Samantha Machado in Bengaluru; Editing by Amrutha Gayathri)