By 1953, Tarmac was processing over two million tons of slag per year while its road surfacing activities had developed into a substantial civil engineering business in its own right.

During the 1950s and 1960s, it acquired numerous competitors, becoming the largest roadstone and construction group in Britain in 1968 following a three way merger between Tarmac, Derbyshire Stone and William Briggs.

During the 1970s, Tarmac Group made a decisive shift towards private home construction; by the end of the decade, it was building 4,000 houses annually and would become the largest housebuilder in Britain.

At the end of the 1980s, its housebuilding activities accounted for half of Tarmac Group's profits, somewhat overshadowing its performance in other areas, such as its expansion into North America and other international markets.

Nevertheless, the company gradually expanded its geographic coverage (particularly in the south east), increased its production of paving slabs and moved into road surfacing as well as supply.

[7] As with so many companies in the construction industry, the Second World War increased the demand for Tarmac's services, notably for surfacing the large numbers of airfields being built or modernised.

By the time of its half centenary in 1953, Tarmac was processing over two million tons of slag per year, its road surfacing had developed into a significant civil engineering business, and its Vinculum subsidiary "had become one of the major precast concrete undertakings in the country.

While leading the roadstone division, Martin had been responsible in 1959 for the acquisition of local competitor Tarslag and Crow Catchpole, which gave it a greater presence in the south east.

[10] In 1968, Martin engineered the three way merger between Tarmac, Derbyshire Stone and the Scottish Asphalt company, William Briggs, creating the country's "largest roadstone and construction group".

McLean had been bought to strengthen Tarmac's own poorly performing housebuilding division and the enlarged operation, now run by Pountain, was producing around 2,000 houses per year.

[25][26] Tarmac Professional Services also included a scientific and materials testing consultancy (Stanger), a facilities management company, specialist architects firms, and IT businesses.

[31][32][33] During November 1999, Tarmac, which had been effectively consolidated around its roadstone and road surfacing businesses, accepted a bid from Anglo American Mining in exchange for nearly $2 billion.

[34][35] Within months of the acquisition being completed, Anglo American launched a restructuring of the company, under which a new regional structure for its quarries, asphalt and ready-mixed concrete activities was adopted.

[36] In August 2007, Anglo American announced it would seek to sell Tarmac;[37] however, in February 2008, the company went on to report that it was putting the sale on hold, allegedly due to the economic consequences of the Great Recession.

[44] In February 2011, Anglo-American announced a proposed joint venture with Lafarge that involved combining both companies' aggregates businesses in the United Kingdom.