UK building materials supplier SIG said its chief executive Stuart Mitchell would step down immediately and warned on full-year profit citing weak trading hurt by Britain's vote to leave the European Union.
The news sent its shares down sharply.
SIG named non-executive Director Mel Ewell, who was CEO of infrastructure services provider Amey until March, as its interim group CEO.
SIG shares were down 22%, on course for their worst single day ever.
The company has forecast underlying pretax profit of £75-80m for the year, below the £91.53m expected by analysts according to Thomson Reuters I/B/E/S.
The provider of materials for roofing, insulation and interior fittings reported an underlying pretax profit of £87.4m pounds last year.
Founded in 1957 in Sheffield as an insulation distribution business, SIG had been impacted by delays to some commercial sector projects and subdued demand for technical insulation in the petrochemical and manufacturing sectors, it said.
SIG said the UK repair and maintenance market also remained challenging.
Brexit has hit the British construction industry hard, with business surveys showing the sector suffered its sharpest downturn in seven years in the months following the June 23vote.
SIG reported a 1% fall in like-for-like sales in UK and Ireland in the period from July to October.
Earlier this week, rival Tyman said demand for housing products had softened and that it expected its markets in Britain and Ireland to be flat at best in 2017.
