By 1914 quarrying activities within the city had abated and although most building stone was being acquired from elsewhere sandstone quarries continued to operate in Cathcart and Giffnock. Most extraction was therefore associated with the production of heavy-clay products, particularly building bricks. Although many of Glasgow's finest buildings appear to be built from stone, this is usually only a veneer, the bulk of these structures often being made up of brick. During the late 19th and early 20th centuries, Glasgow's rapid expansion was made possible by the massive output of bricks from brickfields and brickworks, particularly in the east side of the city around London Road. Here the surface clays were suitable for the production of hand-made and extruded red bricks and many examples can be found today within the internal walls of buildings.
As the century progressed, the demand for housing continued and the brick industry adapted by using mechanised brick presses to mould common bricks from the shales found in colliery waste. Several brickworks were therefore founded next to coal mines, such as Frankfield in Shettleston. The common bricks were usually not of sufficient quality to be used as facing bricks therefore many houses built in this period had to be protected by an external render.
Fireclay was also extracted in the Glasgow area and was used to produce a variety of heavy clay products including refractory bricks, chimney cans, drain fittings, sewer pipes and sanitary ware. However, the focus of Scotland's sanitary ware industry was to the west of the city in Renfrewshire, most notably at Barrhead, where Shanks grew to dominate the industry.