After erection the steelwork should receive one or two coats of paint; two coats are to be recommended, in which case they should be of different colours.
In German specifications it is required that the steelwork should first receive a coat of boiled linseed oil, in order that the red lead coating should be more coherent with the steel.
Steelwork that has to come in contact with brickwork or concrete should not be painted, but should receive a wash of cement as the brickwork or concrete-work proceeds.
The steelwork which is exposed to the weather should be painted about every three years, but when it is under cover an interval of five years may elapse.
The following are the requirements of the New York building law in regard to the protection of iron or steelwork against corrosion, &c.: " All structural metal-work shall be cleaned of all scale, dirt and rust, and be thoroughly coated with one coat of paint.
The steelwork for a building of any considerable size is almost invariably rolled to order.