Fig. 7. Foundation Detail
3. Excavations.—Excavations should be made enough larger than the proposed foundation that the mason may have room to wield his trowel in pointing the outer joints, and for waterproofing. An extra foot of excavation upon each side will usually be required.
All foundations must be carried well below the frost line. Excavations should be made accordingly.
4. Foundations; Footings.—Because of the tendency of a building to settle unevenly, due to variations in the strength of the supporting ground or the unequal weight placed upon this ground, foundations must be constructed of some non-yielding material such as brick or stone, and of such thickness and so bonded that the weight of the building may be evenly distributed.
The thickness of wall will depend upon the weight to be supported and upon the character of the soil.
Unless rock or gravel is encountered, every foundation should have a footing, [Fig. 7.] The amount of footing used is usually twice the thickness of the foundation wall. In brick walls this footing draws into the wall by "stepped" courses of brick, each layer being narrower than the one just preceding. For ordinary residence work with ordinary soil conditions a 10- or 12-inch wall resting upon a footing 2 feet wide and 8 or 10 inches deep will suffice.
A safe footing for supporting posts of 66" × 6" yellow pine, for most soils, will be 10 inches deep by 18 inches square. Partition walls carrying no unusual load need not be over 8 inches in thickness.
Fig. 8. American Bond
