CREAMERY CONSTRUCTION 37 



Pitched Roof. — Materials recommended as fireproof for a 

 pitched roof are asbestos shingles, clay tiles, metal tiles, and 

 slate. 



The pitch of the roof is obtained by dividing the height by 

 the span; thus we speak of its being one-half, one-third, and 

 one-fourth pitched. 



PAINTING 



Paint consists of a liquid carrier with which is mixed a solid 

 substance called pigment which gives the color desired. For 

 ordinary painting, this liquid consists of linseed oil; but for 

 enamel paints, varnish is used. White pigments consist of white 

 lead, white zinc, or zinc lead.' Yellow is commonly chromate 

 of lead, or chrome yellow. Green is chrome green — a mixture 

 of chrome yellow and Prussian blue. Blue is ultramarine, or 

 sometimes Prussian blue. Brilliant red is usually a coal-tar 

 color, while dull reds and browns are oxides of iron. Others 

 are dull yellow. Black paints are made from carbons such as 

 boneblack, lampblack, or graphite. 



Paints should never be applied to wet or damp surfaces. A 

 plastered wall should first be washed thoroughly with a solution 

 of soap and next with a solution of alum. After it is entirely 

 dry, a coat of oil should be applied, and then the paint. If ap- 

 pUed directly, the paint will be attacked by the hme in the 

 plaster. 



Knots, sap, and defects in the woodwork should be thoroughly 

 covered with one coat of shellac reduced to the proper consist- 

 ency in pure grain alcohol. All joints, nail holes, and similar 

 defects should be filled level with white-lead putty after the 

 priming coat has been applied. 



Priming Coat. — The priming coat is the first paint applied, 

 and usually consists of ordinary paint and raw linseed oil mixed 

 in equal proportions. A gallon of priming coat will cover about 

 300 square feet. All exterior woodwork that is to be painted 

 should be primed immediately upon its delivery to the premises. 



' Kidder, Architects' and Builders' Poclcetbook, 1912, p. 1403. 



