When cutting your own crown molding and trim molding, there are a lot of different types of wood to choose from. A trim carpenter will make the distinction between two basic grades of trim work; paint grade and stain grade.
Basically, the two terms separate into trim joints that can be caulked and joints that cannot, and will determine the dimensional tolerances that must be adhered to by a carpenter.
Stain-grade work is finished clear, such that the carpenter needs to create near perfect joinery. Paint-grade work can be less exacting, since any minor blemishes and mismatches on joints can be covered up with the skilful application of caulk and primer paint coats.
Hard vs. Softwoods
Stain grade moldings typically are made from more expensive hardwoods; the paint grade trim work is usually softwood, but as always in woodworking, there are the odd exceptions.
The softwood vertical-grain Fir, is sometimes used for both grades moldings. The hardwood Poplar is sold as paint grade molding due to its relatively low expense and durability. Paint grade moldings will often be stocked by millwork shops in locally inexpensive hardwoods like white pine, yellow pine or fir.
Other than whether you want to stain or paint your trim moldings, a trim carpenter will also look at the wood’s workability, which includes how easy it is to cut, shape and sand, and how well it will hold a nail. Soft woods, being more bendable and compressible, conforms better to irregularities and takes well to nailing, so is easier to install.
Tight grained woods such as basswood, pine and cedar give clean cuts and leave a surface that is paint or stain ready, while an open grained wood such as oak or walnut will need to have its grain filled before painting or staining.
Durability of moldings and other trim is also an issue, since trim does receive a fair amount of wear and tear in a house. Several factors influence durability, most notably resistance to rot, dimensional stability, and hardness.
The harder the wood, the more a molding will be able to survive clumsy appliance movers, house cats sharpening their claws, or kids throwing things.
In damper areas of the country, rot resistance will be important. This is also a consideration if trim will contact masonry, since it will wick moisture into the trim. Good rot resistant woods are cedar, cypress and redwood.
Dimensional stability is the amount of shrinkage or expansions that a given length of trim will undergo given a certain amount of moisture content in the air. Wood trim absorbs and releases moisture with changes in the relative humidity levels in a house, be it from humid weather, cooking, taking showers or appliances running.
As humidity changes, wood shrinks and swells along the direction of its grain; as a result, paint can crack and joints will open up gaps. Woods of high dimensionally stability include rift sawn oak, vertical grain redwood and sugar pine.
Molding Woods List
Whether you make your own molding, buy it off the shelf, or have it custom made here is a list of woods for crown molding, baseboard molding and other trim work.
White Ash: this is alight brown to creamy white colored hardwood of open grain, best used for stain grade work. It has a bold grain, is strong and springy and has dimensional stability on the low end of the spectrum.
Beech: this is a closed grain wood that is very hard, but with poor dimensional stability. It is inexpensive, white to reddish brown in color, and best used for paint grade work.
Yellow Birch: One of the more commonly used woods, it is good for stain grade and superior for paint grade moldings. Closed grain hardwood white to dark red color.
Butternut: Pale brown and medium hardness, it is used for stain grade trim. Gives a rich appearance, medium dimensional stability, is not widely stocked.
Cherry: Closed grain hardwood of reddish brown color. Gives a rich appearance, superior for stain grade work. Medium dimensional stability.
Douglas Fir (vertical grain): Closed grain softwood, red-tan color good stability, good for wither paint or stain grade.
Douglas Fir (flat grain): Same as vertical grain, except has a tendency to splinter, costs less and has grain that easily raises.
Maple (hard type): Extremely hard wood that is white to reddish brown. Closed grain, lower in dimensional stability, good for stain grade, superior for paint grade. Soft maple is not widely used, although it has better dimensional stability.
Red Oak (plain sawn): Open grain, reddish tan to brown color hardwood. Superior for stain grade, it is a low cost and widely used architectural wood.
Red Oak (riftsawn): Same as plain sawn red oak, except has excellent dimensional stability.
Idaho Pine: Creamy white softwood that has good dimensional stability. Very good for paint grade and good for stain grade. Closed grain, true white pine that has a large variety of architectural applications.
Northern Pine: Creamy white to pink colored softwood. Dimensional stability good. Very good for paint grade and good for stain grade. Closed grain, true white pine that has a large variety of applications.
Ponderosa Pine: Most widely used pine. Closed grain softwood of light to medium pinkish color. Very good for paint grade and good for stain grade.
Sugar Pine: Closed grain softwood, cream white color, and excellent dimensional stability. Very good for paint grade and good for stain grade. True white pine, many applications.
Poplar: Closed grain medium hard wood, pale yellow to brownish color. Has excellent paintability. Superior for paint grade and good for stain grade.
Red Western Cedar: Very good rot resistance, softwood with closed grain, light to dark red colored. Medium dimensional stability.
Redwood (vertical grain): Deep red softwood of closed grain that is superior for stain grade and paint grade work. Very high dimensional stability, high rot resistance.
Redwood (flat grain): Deep red softwood of closed grain that is good for stain grade and paint grade work. Medium dimensional stability, high rot resistance.
Walnut: Open grained hardwood, high cost, excellent for stain grade work. The sapwood is creamy white colored, the heartwood is medium to dark brown colored. Low dimensional stability.
Photos by Tall Chris(top) and Lamerie (beechwood swatch), Creative Commons Attribution License