CSR also announced a $375 million equity raising to facilitate a demerger of its sugar business.
Due diligence on the demerger proposal is well advanced and has confirmed that the process will increase shareholder value, the company said.
CSR booked an impairment of $250 million in the six months to September 30 on its Viridian glass business, due to the decline in construction markets and a high Australian dollar, it said.
First half profit excluding significant items was $96.6 million, up 35 per cent on the previous corresponding period.
Earnings before interest and depreciation (EBIT), before significant items, was $216 million, up 22 per cent on the previous corresponding period.
The group reaffirmed its guidance of a slightly improved full year earnings performance than the previous year's $320.1 million.
The sugar business benefited from increased crushing volumes, an earlier start to the crush and a higher raw sugar price.
The decline in residential and commercial construction markets in Australia and New Zealand since last year impacted the earnings of the building products division.
"However, leading indicators suggest that conditions will improve in the second half," CSR said.
Australia Post profit divesFirst Horizon loss narrows
