How to Choose a Paint Roller
by: Dale Cox
You will want to use a roller if you need to cover walls, ceilings, and other wide spaces with a smooth, uniform coat of paint. In addition, if you have a lot of smaller areas like flat doors, kitchen cabinets, and built-in bookcases to paint, you'll want to use a mini roller to make those jobs go easier while also improving on the finished results you could achieve using a brush alone.
Choosing the best paint roller to use for any particular job isn't complicated, there are only a couple of important points to consider. First, what type of surface are you dealing with? Is it very rough with lots of crevices and ridges, is it very smooth and highly visible, or is it somewhere in between? The surface texture, more than anything else, will dictate the length of absorbent fibers, called the roller cover nap, you'll need to choose in order to achieve consistently smooth coverage with your coating.
Secondly, what type of coating are you using? Is it oil or water-based? Is the coating very shiny like high-gloss enamel or does it have a duller finish like semi-gloss, eggshell or flat wall paint? The type of paint will help determine the nap material to choose and the sheen will help in determining the nap length.
Choosing Roller Nap Length
When you choose a paint roller cover, sometimes called the sleeve, you are essentially choosing the nap. Roller nap varies by length and the material used to make it. Typical nap lengths you'll find at your local homes store include 1/4, 3/8, 1/2, 3/4 and 1 inch.
As a general rule, surface texture will determine the nap length to choose. For example, a rough surface like thick drywall texture, stucco, or masonry will require a long nap of 3/4 inch or more to force paint into the uneven finish. Choose a short nap of 1/4 to 3/8 inch when you have a very smooth surface to paint with an oil-based paint or a coating with a shiny finish. This would include applying high-gloss paint to drywall or plaster and when painting smooth wood like kitchen cabinets and built-in bookcases.
For most other jobs around the house including walls and ceilings, choose a medium nap of 3/8 to 1/2 inch. These will produce a consistently smooth coat with minimal spatter and roller marks, even when using an eggshell or semi-gloss finish.
After the surface texture, the coating type and finish should be considered when choosing the length of roller nap and, in some cases, the nap material as well. For instance, when using an oil-based coating or varnish, a short poly/wool nap of about 1/4 inch is the best choice. This is particularly true if you're applying one of these finishes to a very smooth surface. For latex semi-gloss, eggshell and flat paints, a poly/nylon nap of 3/8 to 1/2 inch makes the best choice.
Choosing Nap Material
Roller nap is made using: polyester, nylon, wool (also called sheepskin), mohair, polyurethane foam, and microfiber. Most nap is made using a blend of a couple of these materials like polyester and nylon. Your roller nap material and density will have a good deal of impact on the results of your paint job. For example, a high quality cover will greatly improve the smooth appearance of a paint coat and minimize the effort required to apply it as compared to a lower quality cover.
In general, quality equates with nap density. The density of a roller cover is a result of whether the fibers are woven or knitted into the core. Woven fibers create a thick, springy nap and will produce a smooth, consistent finish in any paint coat. Although quality woven rollers are a good choice no matter what sheen you're using, if you're using a very shiny or oil-based coating, they are a must to avoid problems like roller marks and "hairs" in the paint finish from shedding fibers.
Knit roller nap is spaced farther apart and not as substantial as woven nap. These covers will usually be cheaper too. Knit covers tend to shed easily, even with the more expensive models, making them good for rough jobs around the house, but not much else if appearance is an important concern.
By far the most common rollers you will find at your local store are poly/nylon and poly/wool blends. Poly/nylon is typically used for water-based latex paints and poly/wool for oil and alkyd-based paints. Pure wool has traditionally be used almost exclusively for oil and varnish coatings because it's not prone to shedding fibers which can ruin the shiny effect of the paint job. The trend for shiny oil-based coatings now, however, is to use a woven poly/wool nap that can produce comparable results at a lower price.
Microfiber rollers are the latest trend in nap for both latex and oil paints. These rollers are great for applying a very thin, smooth coating that can be comparable to a spray paint finish. This makes microfiber ideal for varnish and high-gloss oil-based paints applied over very smooth surfaces where too much paint can create problems with roller marks, but not so good for covering walls and ceilings where more paint is needed over a large area.
In addition to the traditionally stringy fibers used for roller covers, polyurethane foams are also used to make nap and pad-type brushes. While foam rollers can produce a smooth finish with high-gloss finishes, they can also be difficult to work with. Repeated strokes can spread the paint too thin leaving streaks in the finish. Using these rollers can also get expensive as they can usually only be used once, where as a fiber roller nap can be washed out repeatedly with a roller spinner and used again.
To choose a roller at a glance, check the chart below. Roller nap and length recommendations are provided depending on the surface you're dealing with and the type of paint and sheen of you're using.
Choosing Roller Cover Size
Roller covers are made to fit onto a spinning wire frame which can then be threaded onto an extension pole for a longer reach. Typical cover sizes you will find at paint and home stores include: 9, 7, and 4 inch lengths with a 1-1/2 inch hollow core.
Choose your roller size based on the size of the area you need to paint, a standard 9 inch tool is a good choice for most interior painting on walls and ceilings. A 7 inch size is also commonly available and may be a good choice if you're not comfortable with the slightly larger one. But as a separate tool, it doesn't offer any particular advantages over the nine inch roller. You can also find a much larger, "jumbo" roller at most paint stores but at 18 inches long, these are way too big for most home diy. Jumbo rollers are mostly used by professionals on large jobs with lots of space to cover quickly.
In addition to the standard sizes, mini, or sausage rollers are also available for small and hard to reach spaces such as built-in shelves and kitchen cabinets. While the standard four inch cover is just a stubby version of the larger ones, a sausage roller is a thin 1 inch round and about 6 inches long and made to fit onto a long, thin handle. This slender design makes it a better choice than the 4-inch for easy maneuvering in tight places like inside cabinets, while still delivering good paint coverage.
Choose Quality Over Price
Always choose a good quality roller for your project, especially when painting inside the house. The higher quality will cost just a little more than the cheaper version but will deliver much better results with less effort. Quality roller covers will last much longer too, making them more economical in the long run.
You can usually rely on the price to correspond to quality when choosing a roller but not always, so look for a few telltale signs. First, the nap on a cheap roller is not as dense as that of a top quality tool. To test nap density, wrap you fingers around it. You should not be able to feel the inner core on the quality roller when you squeeze it in your hand. Even if it has a short nap, it will still have plenty of cushion between your fingers and the core. Hold two rollers of differing price in your hands at the same time to feel the difference in nap thickness. The cheaper nap will seem to barely exist, while the quality one will feel substantial and springy.
Another test of quality is the core itself. A cheap one will be made of cardboard or hard polymer-bond plastic, while a quality roller core will likely be made of phenolic resin. This better quality will stand up to many paint jobs and can be washed repeatedly, while the cardboard core in a cheaper roller will breakdown after only a couple uses. Even with a more durable plastic core, the nap on cheap rollers will shed excessively leaving unsightly fibers in your paint finish that can ruin the job.