Portland Cement, with a large proportion of sand, as much as 90 per cent., is useful for internal work; it may be used as a backing for a thin floating of the white cements.
The heavier and slower in setting cements are generally the stronger; but in such plasterer's work as rendering walls the quicker setting cements may be used without disadvantage.
Roman Cement is a "natural" cement. It is liable to effloresce on the surface, but is useful where quick setting with expansion is required, as in underpinning or repairs, without any great ultimate strength.
Other "Natural Cements" very similar to Roman are Medina, Rosendale, Windsor, etc., and are also useful where quick setting is required.
The Use of the Natural Cements is much restricted at the present time as compared with artificial cements, such as Portland.
Parian Cement is valuable for internal work, because of its hardness, nonporosity, and quick setting properties. It is hence useful in cases where the walls, moldings, etc., have to stand rough usage. It is also washable. This cement cannot be reworked.
Keene's Cement is one of the most useful of the artificial cements. It is harder than the other kinds made from plaster of Paris, and is much used for pilasters, columns, etc.2 as it sets quickly and can be polished, and takes paint excellently.
Martin's Cement is much the same as Keene's, and used principally for dadoes, etc. In proportion to its bulk it covers a large proportion of surface. It can be painted, etc., as Keene's.
Robinson's Cement has many advantages, among which are its fire-resisting qualities and suitability for use on concrete. It is also cheaper than other like cements.
Adamant is another white cement, which is useful for work where hardness, facility of application, quick drying, and a fine surface are required.
The Above Cements have plaster of Paris (calcined gypsum) for their base, and are only adapted for internal uses, to which they are eminently suited. They can all be brought to a good surface, and can be painted almost at once.