** Building materials manufacturer Welspun Corp WGSR.NS rises 9.9% to 894.1 rupees after Q4 results
** Stock set for best day in three years, if gains hold
** Co's projects revenue growth of 25% in FY26, benefiting from demand for oil, water and hydrogen pipelines
** Revenue declines 19.4% in FY25 and 12.7% in Q4
** Still WGSR's profit more than doubles to 6.98 bln rupees ($81.50 million) from 2.68 bln rupees a year ago, benefiting from fewer costs amid lower sales
** With session's gains, WGSR up 48.6% in the last 12 months
(Reporting by Ananta Agarwal in Bengaluru)
((Ananta.Agarwal@thomsonreuters.com))