BPB, the world's biggest plasterboard manufacturer, has unveiled a 13% rise in half-year profits.
The UK firm, which makes ceiling tiles and insulation materials, said underlying profits in the six months to September 30 rose to £107.8m ($184m).
The firm said it had benefited from growing sales of plasterboard and stable volumes of building plaster.
BPB and three other building material firms were fined last year by the EU
for fixing the price of plasterboard.
The European Commission slapped French group Lafarge with the biggest fine - 478m euros (£306m; $475m).
BPB was told to pay 138.6m euros, while Germany's Knauf was fined 85.8m euros and Belgium's Gyproc 4.32m euros.