Paint rollers can be used with almost any type of paint—gloss, flat, latex or oil-base—and they may be used on most rough surfaces, also on smooth walls and ceilings.
Rollers can be bought with several different kinds of covers, each varying as to the type of fiber used and as to the length (or depth) of the nap. The most popular is a medium-length nap (3/8 to 1/2 inch), lamb's wool type of fabric, generally made of a synthetic fiber instead of real lamb's wool. This is the cover most often utilized for painting walls and ceilings, regardless of whether a latex or alkyd-based flat is being used. Short-nap mohair covers are likewise available for use with glossy or semi-gloss enamels. These covers leave less or no stipple at all, so they give a smoother job when a glossy, finish is needed.
Deep-pile rollers, which have a longer nap, are also available. These have fibers which may be either 3/4 or 1/14 inches in length. They are specifically made for use on rough surfaces, like porous concrete, cinder block or stucco, and they can even be used for painting woven wire fences and coarse-textured ceilings. The extra-long fibers on this type of cover permeate into all the crevices and indentations, and it would do the job much quicker than a brush.
Irrespective of the type of cover required, homeowners must never purchase a roller or roller cover based on price alone. Cheap rollers are more difficult to dismantle and clean. They also might not work as smoothly since they usually have inefficient bearings and badly designed handles. A good quality cover would be made of fiber that won't mat, cake or shed. The core will be made of hard plastic so that the cover can stand repeated washing without falling apart.