Two investment funds, CVC Capital Partners and Advent International, will turn the five speciality products arms into a company run by the present management and Lafarge will buy back a one-third stake.
A further minority stake is also expected to go to US private-equity firm Carlyle Group.
The only speciality products businesses not to be sold are road marking, the European arm of which was sold to Burelle Group, and lime, which is operated in the USA as part of a joint venture with Carmeuse.
These deals are part of a package to raise £1bn to help restore Lafarge's "financial flexibility". The speciality products division had sales of £1.2bn in 1999, 12% of the group's total.
The five businesses sold off are involved in aluminates, mortars, admixtures, refractories and paints.