Choosing a roller nap for walls, ceilings and trim

What nap is, and what it does

Nap is the length of the fibers on a roller cover, measured in fractions of an inch. A longer nap holds more paint and reaches into the dips of a rough surface. A shorter nap holds less, lays paint down more evenly and leaves a smoother finish.

Wooster Brush puts the trade-off simply: a shorter nap suits smooth surfaces, a higher nap suits rough ones, and some painters use a longer nap on smooth surfaces to work faster, but a higher nap may leave a textured look there. This Old House warns that a long nap indoors can give too messy a texture. In other words, the nap should match the surface, not the other way around.

A nap chart by surface

The makers' ranges overlap a little. This Old House puts lightly textured walls and wood paneling at 3/8 inch, where Benjamin Moore moves textured walls to 1/2 inch. If you're between sizes, start with 3/8 inch and try a section. If the wall looks thin or hard to cover, step up. If it looks pebbly, step down.

Match the nap to the actual wall

Run your hand over the wall in a side light. If it feels smooth, 3/8 inch is the right start, and 1/4 inch works if it's glass-smooth or you want the very finest finish. If you can feel a texture with your palm, use 1/2 inch so the fibers reach the low spots. Deep bumps need the longer naps listed for stucco and masonry.

Rooms often have more than one surface. The ceiling and walls might take 3/8 inch, the door and trim 1/4 inch, and a textured accent wall 1/2 inch. Buy a few covers rather than forcing one to do everything. Our guides to painting interior doors and painting baseboards cover the smaller surfaces.

Why sheen changes the choice

The glossier the paint, the more any roller stipple shows. Dunn-Edwards explains that higher sheen paints reflect light more directly and enhance the perception of shadows and highlights, while lower sheens scatter the light. A flat paint hides a little stipple. A satin or semi-gloss shows more of it.

So pair higher sheens with shorter naps. A satin hallway rolled with a 1/2-inch cover will show more texture in window light than the same paint rolled with a 3/8-inch or 1/4-inch cover. Our paint finish for each room guide helps with picking the sheen in the first place.

Cover material: woven, knit, microfiber and foam

The fabric matters as much as the nap, and the right one depends on the paint. This Old House says synthetic fibers such as polyester and nylon suit water-based paint, natural fibers like lamb's wool suit solvent-based paint, and microfiber works well with latex. Foam covers suit oil-based paints and varnishes.

• Woven covers. Benjamin Moore describes woven covers as shed-resistant and suited to smooth, semi-smooth and semi-rough surfaces, which makes them a good default for interior walls.
• Knit covers. These resist matting and are designed for low-sheen paints, stains and primers, according to Benjamin Moore.
• Microfiber covers. Benjamin Moore describes a blend built for high capacity and consistent paint release, and This Old House says microfiber works well with latex.
• Foam covers. This Old House says foam suits oil-based paints and varnishes.

If you're painting walls with latex, a woven or microfiber cover in the right nap is the safe pick.

Quality shows in the details

Cheap covers shed fibers, and every fiber ends up in the paint. Benjamin Moore says to look for beveled edges, no visible seams and a plastic core, and to squeeze the cover to see whether it bounces back. Inexpensive covers tend to shed fibers and break down after repeated washing, and a quality cover should last up to five uses before it starts to shed.

Prepare every new cover. Benjamin Moore suggests wrapping painter's tape around your hand, sticky side out, and rolling it over the cover to lift loose fibers. This Old House suggests washing a new roller with water and mild soap to remove manufacturing residue and letting it dry completely before you use it.

Frame, size and pole

A 9-inch cover on a sturdy frame is the standard for rooms, because it holds enough paint to work efficiently and is still easy to control. A wider cover covers more per pass but is heavier and harder to keep even. Smaller 4-inch covers on a mini frame are for doors, trim and tight spots.

An extension pole helps with the ceiling and also lets you roll a wall from top to bottom in one stroke, which makes it easier to keep a wet edge.

A buying checklist

1. Check the surface. Smooth wall, light texture or heavy texture decides the nap.
2. Check the paint. Latex or acrylic wants a synthetic, woven or microfiber cover. Oil-based paint wants the covers made for it.
3. Pick the nap from the chart: 1/4 inch for doors and trim, 3/8 inch for most walls and ceilings, 1/2 inch or longer for texture.
4. Look at the cover itself. Beveled edges, no seams and a plastic core, and it should spring back when squeezed.
5. Buy a spare. A second cover means you can swap when the first one gets loaded or starts to shed, without stopping a wet edge.
6. Prep it before you paint. Pull the lint off with tape, or wash a new cover and let it dry.

That list takes five minutes in the store and saves an afternoon of fixing marks later. If you've already rolled a wall and are unhappy with the texture, see how to fix it in our guide to avoiding roller marks.

Where a roller isn't the right tool

Rollers are for walls and ceilings. Cabinets are a different kind of job: the doors and drawer fronts get sprayed, and the frames are finished in your kitchen. Our guide to spray painted kitchen cabinets explains why sprayed doors come out so smooth.

For walls, we cover floors and furniture first and repair small holes before any roller comes out, as part of our interior painting. Most rooms take one to two days, and the quote includes the paint. Ask for a free estimate and we'll talk through the room.