CHAPTER III 



SITE— FOUNDATIONS AND FOOTINGS— DAMP COUKSE 



Site. — The site for buildings should be dry and healthy, and free from 

 rotting or fermenting organic matter. 



Foundations. — A good foundation is one which will remain equally firm 

 under all parts of the walls of the building. If the foundation soil is hard 

 at one place, and soft at another, the walls borne by the soft part will 

 settle more than those on the hard part, resulting in the formation of 

 settlement cracks in the walls. A site should therefore be chosen where 

 the subsoil is of uniform hardness and texture horizontally. 



"Footings" of walls should, if possible, rest on solid or virgin soil, 

 " made " ground being avoided or removed. 



An excellent foundation is afforded by deep beds of gravel. The gravel 

 should be disturbed as little as possible while excavating. 



Clay containing a large proportion of grit also forms a good foundation, 

 but more nearly pure clay soils should be avoided, because the purer the 

 clay is, the more is it affected by changes in the weather, expanding in 

 wet weather and contracting in dry, to an extent which may unsettle 

 the footings. 



If a building is to be erected on a hillside the foundations should be 

 stepped, or " benched," so that the footings rest on horizontal, and not on 

 slanting, surfaces. 



Buildings should not be erected on ground containing ant nests or ant 

 channels. 



The foundation trenches should be excavated until a solid layer is 

 reached. In South Africa they seldom need be deeper than 18 inches for 

 single-storey buildings. 



The bottom of the foundation trenches should be hard. It may be 

 tested by blows from a tool, when variation of sound will indicate any 

 underlying soft places. Such bad parts should be excavated or, if possible, 

 rammed until hard, indeed it is advisable to ram all over the bottom 



