British architect, born in Philadelphia, PA. He worked in Fowler's and R. Smirke's office before setting up his London practice in 1830, and in 1832 won the competition to design the new Hall of The Fishmongers' Company beside Rennie's new London Bridge. It was a masterly composition in the Greek Revival style with more than a touch of Smirke's influence (Roberts had assisted Smirke on the working-drawings for the British Museum), and included many interesting features such as an ingenious plan, the use of cast and wrought iron in the construction, the inclusion of four unfluted Greek Doric columns of polished Peterhead granite in the entrance-hall and stair (among the first instances of this material being used for such a situation and object), the employment of a huge concrete raft for the foundation, and quotations from the refined Greek Corinthian Order of the Choragic Monument of Lysicrates in Athens in the main Hall itself. His pupil and assistant at the time was George Gilbert Scott.
Roberts developed a successful practice, designing country-houses for members of the aristocracy with liberal and Evangelical tendencies. These buildings were in a Jacobethan, Tudor Gothic (Norton Manor, Norton Fitzwarren, Som. (1843), or pleasing Italianate (Escot House, Devon (1838) styles. His essays in Gothic Revival churches, however (e.g. St Paul's, Dock Street, Whitechapel (1846) did not meet with the approval of the Ecclesiologists.
However, it is as the architect of a number of philanthropic buildings that Roberts is of world importance. His Evangelical leanings brought him into contact with those who wished to improve society by example. His first essay was the Destitute Sailors' Asylum, Whitechapel (1835), but in 1844 he became Honorary Architect to the Society for Improving the Condition of the Labouring Classes (SICLC), with which Lord Shaftesbury (1801–85) and Prince Albert were to be so intimately involved. For the Society Roberts designed a great variety of exemplary buildings, including houses in Lower Road, Pentonville, London (1844—demolished), various lodging-houses, and the epoch-making Model Dwellings, Streatham Street, Bloomsbury (1849–51). The last provided very advanced standards of accommodation, fire-resistant construction using vaulted floors and concrete, and gallery access which Roberts argued were elevated streets to individual houses, thus avoiding window-tax which would have been imposed on a large building. As a result of this building and Roberts's arguments the Government was obliged to abolish both window-tax and other enactments, making it more economical for philanthropic organizations and private individuals to provide dwellings for the labouring classes. Roberts developed the plan of a typical apartment evolved at Streatham Street for his ‘Model Houses for Four Families Erected in Hyde Park at the Industrial Exhibition of 1851’ paid for by the philanthropically motivated Prince Consort to further the aims of the SICLC of which he was President. This brilliant design had four self-contained apartments, each with its own toilet facilities, access from an open stair, excellent insulation and fire-proof construction, and with a standard of accommodation far in advance of its time. The exhibit (the first of its kind in the world, long before the much-trumpeted Weissenhofsiedlung of 1927) was visited by thousands of people, and the Society published the detailed plans and elevations. Roberts's designs were influential throughout Europe and the USA, and versions of his plans were still being used in Amsterdam South in the 1920s and 1930s. His designs for model cottages for the country were also published, and built in numbers throughout the United Kingdom from 1851: most were in a vaguely C17 style, but this could be varied according to local circumstances and taste. An entire estate of his model dwellings, with a version of the Great Exhibition (or Prince Albert's) model dwellings, was built at Windsor, Berks. (1852), and survives virtually intact.