A saw-tooth roof is a

roof A roof ( : roofs or rooves) is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temp ...

comprising a series of ridges with dual pitches either side. The steeper surfaces are glazed and face away from the

equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can al ...

to shield workers and machinery from direct sunlight. This kind of roof admits natural light into a

deep plan A deep plan building is a building in which the horizontal distance from the external wall is many times greater than the floor to floor height. Deep plan buildings make more efficient use of site area. They also cost less to build per unit floor ...

building or

factory A factory, manufacturing plant or a production plant is an industrial facility, often a complex consisting of several buildings filled with machinery, where workers manufacture Manufacturing is the creation or production of goods with t ...

Advantages

Before electric light substituted for daylight in the late 19th century, consideration of good daylight strategies was essential. The sawtooth roof, with its glass panels facing away from the equator, blocks the light and heat of direct sun exposure and provides uniform, natural light over a large area. Historically they were used in industrial and manufacturing buildings as the primary light source. Some architects think that sawtooth roofs look best when grouped in rows of three or more. Sawtooth roofs allow more efficient use of headroom and floor space. It is easy to install beams, columns and attractive elevations in the design of the roof. Sawtooth roofs provide for maximum headroom compared to flat roofs.

History

19th century

British engineer and architect

William Fairbairn Sir William Fairbairn, 1st Baronet of Ardwick (19 February 1789 – 18 August 1874) was a Scottish civil engineer, structural engineer and shipbuilder. In 1854 he succeeded George Stephenson and Robert Stephenson to become the third preside ...

is sometimes credited with the first designs for what he termed the ''shed principle'' possibly as early as 1827. In his, "Treatise on Mills and Millwork", of 1863, Fairbairn states that, 'Contemporaneous with the architectural improvements in mills

rom 1827 Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * R ...

the shed principle lighted from the roof, or the "saw-tooth" system, came into operation. It was chiefly adapted for power-weaving...' It was rapidly adopted during the industrial revolution for the many new ''daylight factories'' where good natural lighting was essential in the manufacturing process and large areas of enclosed space were required to house the machinery. The first documented example can be found on the Weaving Shed (and perhaps also the Combing Shed) of

Titus Salt Sir Titus Salt, 1st Baronet (20 September 1803 in Morley – 29 December 1876 in Lightcliffe), was a manufacturer, politician and philanthropist in Bradford, West Riding of Yorkshire, England, who is best known for having built Salt's Mill, a ...

Saltaire Saltaire is a Victorian model village in Shipley, part of the City of Bradford Metropolitan District, in West Yorkshire, England. The Victorian era Salt's Mill and associated residential district located by the River Aire and Leeds and Live ...

Mills near Bradford, which were founded in 1851.

Decline and readoption

There was a decline in its use when artificial lighting became prevalent, but the design re-emerged in the last quarter of the 20th century and early 21st century, as architects and designers placed greater importance and value in introducing natural light into buildings for environmental efficiency. Reasons for the renewed interest in

daylighting Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that sunlight (direct or indirect) can provide effective internal lighting. Particular attention is given to daylighting while designing a bu ...

include the high cost of fossil fuels and the realization that sources of electricity have a finite life. Less tangible aspects of daylighting relate more to the human spirit and quality of life. The sawtooth design, often seen on factory roofs, has won praise for its potential for renewable energy. Judges of the British Construction Industry's award recognised that the distinctive shape offers potential for solar panels to be installed. Sawtooth roofs, in which opaque modular elements are combined with transparent surfaces, whether inclined or in various shapes, have become prevalent again. The exact dimensioning of these roofs is extremely important both in terms of energy savings, due to the reduction in electricity needed for artificial lighting, and as regards vision quality.

Examples

The Central Telephone Exchange, Melbourne, built approximately 1919, provides an early example of a reinforced concrete sawtooth roof. The

Sawtooth Building The Sawtooth Building is a historic 1913 brick and steel industrial structure in Berkeley, California which was built to serve as the West Coast manufacturing headquarters of the Kawneer Manufacturing Co. It gets its name from the saw-tooth roof ...

is located at 930 Dwight Way, Berkeley, California, and also known as the Kawneer Manufacturing plant. Early 20th-century industrial buildings in Japan often feature this design. A sketch of the saw-tooth roof form is available from the Ministry of the Environment in New Zealand.

References