Concrete Chimney Caps
As a large proportion of fires in residences originate in the chimney, it is well to have this part of the house as nearly fireproof as possible. It can be made entirely so by building it of concrete. If this is not convenient, at least let the chimney cap be of concrete.
These caps are cast in one piece, on the ground, and in any shape desired.
The outside form is a wooden box, with inside dimensions corresponding with the outside dimensions of the desired cap. Usually the cap is 6 inches thick, and has an “over-hang” or “drip” extending on all sides beyond the outside of the chimney.[3] Thus, if top of chimney, over all, is 18 inches square, make outer form 22 inches square, an extra allowance of 2 inches on all sides, thus obtaining a cap that will have an “over-hang” of 2 inches all the way around.
The inside form may consist of a piece of terra-cotta tile. If more than one opening is desired in the cap, use two pieces of tile or as many as there are to be openings.
Mix concrete 1: 2: 4, the mixture to be a thoroughly wet one. Place in the form, after greasing outside of terra-cotta so that same may be easily removed. Leave undisturbed for two days. Remove forms and place cap in position, attaching it to the brick chimney with a cement mortar, one part cement to one part sand.
