ROCK SLAB FIREPLACE 



ADAPTATION TO LOCATION AND USE 



This fireplace of simple design and construc- 

 tion is not massive. It is low and inconspicuous 

 and well adapted for picnic use, especially in 

 areas where the fire hazard is small. The open 

 end should be toward the prevailing wind. 

 This type without removable plate is not well 

 adapted for use on camp grounds. (See pi. 

 Ill A.) 



Since the construction of this fireplace is 

 dependent upon the availability of the desired 

 kind of large stones, laid without mortar, its 

 adaptation to certain sites is limited. 



Some question has been raised concerning 

 the problem of maintenance in this fireplace, 

 where the intense heat comes in direct contact 

 with the stone, and especially where it is 

 necessary to douse the fire. If the proper kind 

 of heat-resisting stone is available (as de- 

 scribed under "Stone"), the maintenance ex- 

 pense should be no greater than in any other 

 fireplace . Sometimes a sheet iron plate is used on 

 either side of the standard grate in order to pro- 

 tect the stone against the heat (pi. III-A, fig. 2). 



DESIGN AND CONSTRUCTION 



The grate is entirely separate from the rock. 

 These rocks should be somewhat irregular. 



with the exception that the ends should be 

 roughly dressed, as should the top (to provide 

 a shelf on which to set pots and pans). The 

 rock used in this fireplace must be of the heat- 

 resisting kind. The stones on either side are 

 sunk about one-half of their height into the 

 ground and the tops of the stones are level 

 with the top of the grate. The ends of the 

 stone should be set as close together as possible 

 in order to prevent a cross draft in the firebox. 

 They can easily be replaced if damaged by 

 heat and water. 



The grate is anchored by being attached to a 

 concrete block as shown on figure 4, or by being 

 attached to a "log dead-man" (fig. 6). The 

 hearth is usually made of sand or mineral earth 

 and is level with surrounding ground. 



The length and width of the firebox is depend- 

 ent upon the size of the standard grate which is 

 adopted. The height of the firebox should be 

 normal, that is 9 to 12 inches. 



VARIATIONS IN DESIGN 



Variations in design are shown in figure 2 on 

 plate III, and also in plate III A. Sometimes 

 the stone at the end may project slightly above 

 the top of the grate to form a raised back 

 which has a tendency to improve the draft. 



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