For high gloss trim paints, alkyds are usually preferred. Flat paints are attractive and are often preferred on siding, masonry and stucco. Exterior wood stains, available in solid or semi-transparent types, are popular for textured wood surfaces. Solid stains hide the color of the wood, but at the same time allow the texture of the wood to show through. Coating exterior wood surfaces with clear coatings is a somewhat questionable practice.
Sunlight penetrates the clear coating, affecting the wood surface.
This causes the clear coating to lose adhesion and peel off. If you decide to use a clear finish, it is necessary to set up a strict regular maintenance program. A new clear coating should be applied before deterioration of the old coating begins. Some clear coatings contain ultra-violet absorbers which help to lengthen their life. Ask your paint retailer for a recommendation.