In the Roman Empire, porphyry was transported everywhere from Egypt, for use in key positions on important buildings. Coloured marbles were brought from afar. Most other building materials had to be local, for economic reasons. The results of using local materials are now seen as beautiful, charming and historic. Guidebooks will speak of a "stone district', a "brick district', a "timber chalet district' and a "thatched cottage district' (Figure 9c). Visitors flock to see them. Purchasers bid up the prices of traditional buildings. Developers try to imitate old buildings by using traditional materials. Excepting such districts, modern towns have an astonishing jumble of materials. The following account relates to a short section of Frederick Street, in Edinburgh's New Town:
At street level new shop fronts obscure the original sandstone frontages... Martin's Light Bite Restaurant and John Smith's Wools share a facing of cream-coloured limestone full of crinoid, bivalve and bryozoan fragments. The facing on Millet's is a brecciated serpentine marble, with dark reddish fragments in a pale green matrix very similar to the marble known as Rosso Antico d'Italie, which comes from Genoa. The next shop has a very light grey granite facing from Baveno in the Piedmont district of northwest italy. The Stakis Steak House and the Anglia Building Society have a very dark green larvikite. (McAdam, 1986)
A curious feature of the above assemblage is that the designers of the various buildings probably did not even know what they were doing.
Choice of building materials could be left entirely to market forces, or it could be subject to zoning controls. Within a designated zone, design guidance could relate to the use of materials for roofs, walls, paving, planting etc. If this is not thought acceptable, designers could be required to make a statement of how the proposed building materials relate to those in the surrounding area.