BUILDING CONSTRUCTION 13Q 



In building brick walls care must be taken to select the best 

 bricks for the face, avoiding porous, discoloured and chipped 

 bricks. The work must be levelled and plumbed carefully as it 

 proceeds. The walls should be carried up regularly without step- 

 ping-back. The mortar is important. Cement mortar as described 

 in the section on Building Materials is best for brickwork, being 

 stronger and more impervious to moisture than lime. The faces 

 of walls may be pointed as the work proceeds. This method results 

 in a more durable face than is the case with pointing executed after 

 the walls are built. Walls built in lime mortar should be raked 

 out and pointed with cement mortar after completion. 



For the construction of hollow walls see the section on " Damp- 

 ness in Buildings and its Prevention." 



The joints of all brick walls should be grouted up fully with 

 cement mortar and water as each course is completed. 



STONE WALLS. The methods of building stone walls vary 

 slightly with districts, and consequently with the local materials. 

 Certain classes of stone such as whinstone and Kentish rag cannot 

 be treated in the same manner as flat bedded stones such as stratified 

 freestone. 



A stone wall may be built as random rubble, squared rubble, or 

 coursed rubble. In every case the principle is the same, viz., the 

 observation of building on the natural bed, bonding the stones on 

 a principle similar to that in brickwork and, most important, the 

 introduction of through-going headers or bond stones, one to every 

 superficial yard of walling. 



ROOF CONSTRUCTION. 



It is apparent that in the past the most scanty consideration has 

 been given to roofing animal habitations. Usually the material 

 most available has been used. It is obvious that the type of roof 

 and roof covering best for its purpose is the cheapest in the long run. 



The section on Air and Ventilation emphasises the importance 

 of the open roof for animal habitations. The exclusion of the loft 

 is recommended as desirable. Particularly for cow byres and for 

 stables and piggeries it is important that the roof trusses should 

 form the least obstruction to air and light, and that, if possible, 

 they will present the smallest of surfaces for the lodgment of dust. 

 To meet this requirement the Scottish method of roofing, with 

 rafters and ties set at 18 inches or 20 inches centres, is to be 

 discountenanced. 



All roofs consist of supporting trusses and a roof covering, to 



