What roller nap do you use, 3/8 or 1/2 or longer? Roller cover sizes and cores, nap for roof coatings and rough surfaces, woven vs microfiber vs foam, why rollers are left in paint, saving a wet roller, tray liners, bucket grids and drill mixers
Nap is the length of the fiber on a roller cover, and it is chosen by the surface, not the paint: 1/4 inch for smooth doors and metal, 3/8 inch for smooth drywall and plaster, 1/2 inch for lightly textured walls and ceilings, 3/4 inch for rough textured walls, concrete block and stucco, and 1 to 1-1/4 inch for very rough masonry, granulated roofing and roof coatings. A longer nap holds more material and reaches into texture; a shorter nap leaves a smoother film. On a roof, acrylic and silicone coatings go on with 3/4 to 1-1/4 inch nap covers on 9 or 18 inch frames, out of a 5-gallon bucket with a grid rather than a tray. Painters leave a roller in the paint between coats because a cover that stays wet does not have to be washed; a wrapped wet roller keeps overnight.
C&R RC9-3/8 Roller Cover, 5 sizes, 9 inThe product data lists the RC9 as a 9 in phenolic-core roller cover made in 1/4, 3/8, 1/2, 3/4 and 1-1/4 in napReading a roller cover. Three things are printed on the sleeve: the length (3, 4, 9, 9-3/8, 14 and 18 inches), the nap (1/4 to 1-1/4 inch), and the fabric and core (woven or knit polyester, microfiber, lambswool, foam; phenolic, poly or cardboard core). The frame is matched by length and by stem diameter (1/4 inch for standard frames, 5/16 inch for heavy 5-wire and jumbo frames; jumbo covers have a 2-1/4 inch core instead of 1-1/2). The questions people ask — which nap, what the sizes are, what professionals use, whether frame matters, woven vs microfiber vs foam, why painters leave rollers in paint, how to keep a wet roller, whether to reuse a tray liner, what roof coating does to a roller, how a paint mixer works — are all answered from those three figures below.
Roller covers and the gear around them, question by question
Nap, size and core figures are from the product data on this site; the nap-to-surface pairings are the ones printed on cover packaging across the trade.
Roller covers in plain words
- Nap is fiber length. 1/4 smooth and metal, 3/8 smooth walls, 1/2 light texture and ceilings, 3/4 rough and block, 1 to 1-1/4 very rough and roof coatings.
- Sizes: 3 and 4 inch mini, 9 inch standard (9-3/8 same thing), 18 inch for floors, ceilings and roofs. Jumbo covers have a 2-1/4 inch core and need a jumbo frame.
- Woven sheds least, microfiber holds most and leaves least stipple, foam is for gloss on smooth doors.
- Roof coatings: 3/4 to 1-1/4 inch nap on an 18 inch frame, from a 5-gallon bucket with a grid, to the wet mil the coating data sheet states.
- Painters leave rollers in paint so the cover does not dry out between coats; wrap a wet cover tight in plastic to keep it overnight.
- A bucket and grid replaces a tray on anything bigger than a room, and does not tip on a roof.
- Liners peel clean once the paint dries; a plastic bag over the tray does the same job.
- A drill mixer paddle matches the container: small for gallons, 4-1/2 inch for 5-gallon buckets; run it slow and below the surface.
Questions people ask
Why do painters leave rollers in paint cans?
So the cover stays saturated between coats and does not have to be washed; a damp rag over the bucket for a break, plastic wrap for overnight.
What do professional painters use for rollers?
A 9 inch 5-wire frame with 3/8 or 1/2 inch woven or microfiber covers by the case, an 18 inch frame for ceilings and floors, and a bucket and grid instead of a tray.
Which roller do you use for painting walls?
3/8 inch nap for smooth drywall, 1/2 inch for light texture, 3/4 inch for heavy texture or block; woven for a smooth finish, microfiber for fewer loads.
How do you preserve a wet paint roller?
Wrap it tightly in plastic wrap or a bag with the air squeezed out and keep it cool; latex lasts a day or two that way.
What can I use instead of a paint tray liner?
A plastic bag pulled over the tray and taped, or skip the tray and use a 5-gallon bucket with a bucket grid.
Can you reuse a paint tray liner?
Yes, if it is rinsed while wet; dried latex also peels out of a liner in one sheet.
Is 1/2 or 3/8 nap better for walls?
3/8 for smooth walls, 1/2 for lightly textured walls and ceilings; the surface decides, not the paint.
What roller nap for concrete?
3/4 inch for rough concrete and block filler, 3/8 to 1/2 inch for smooth slabs and epoxy after it is spread with a squeegee.
What is the difference between roller naps?
Longer nap holds more material and reaches into texture; shorter nap leaves a smoother film. 1/4 to 1-1/4 inch covers the range.
How do I know what size my paint roller is?
Measure the cover length (9 inch standard) and the core diameter (1-1/2 inch standard, 2-1/4 inch jumbo).
What is the standard size of a paint tray?
A 9 inch tray holding about a quart; 18 inch trays hold about a gallon for the big frames.
What can I use instead of a seam roller?
That is a different tool for membrane seams; see the seam roller guide linked below. A paint roller does not replace it.
What is considered a short nap roller?
1/4 inch and shorter, for smooth doors, trim, metal and gloss finishes.
What is the trick to painting ceilings?
An 18 inch frame on a pole with 1/2 inch nap, a bucket and grid, flat paint, rolling toward the light in overlapping passes and stopping only at corners.
Are paint trays reusable?
Metal trays indefinitely; plastic trays for many jobs; let the paint dry and peel it, or use a liner.
Is a foam roller better than a pile roller?
Only for gloss enamel on smooth doors and cabinets; foam bubbles with fast latex and does nothing on texture.
What are the disadvantages of roof coatings?
They need a clean, dry, sound roof and the right weather, they do not bridge failed seams, and their life depends on applying the wet-mil thickness the manufacturer states.
What is the difference between a microfiber and a woven paint roller?
Woven polyester sheds least and gives a clean smooth finish; microfiber holds more paint, releases it evenly and leaves almost no stipple.
Does the paint roller frame matter?
Yes: a stiff 5-wire frame with a 5/16 inch stem keeps the cover true and takes an extension pole; flimsy frames flex and track.
What can I use instead of a paint mixer?
A stir stick for a gallon, the store shaker, or boxing between two buckets; for 5 gallons of coating a drill mixer paddle is the tool.
Related guides
SqueegeesRubber vs silicone, notched and floor squeegeesPush brooms, handles and extension polesBristles, braces and telescoping polesSeam rollers and single-ply toolsTPO, PVC and EPDMOSHA safety glasses requirementsWhat 1910.133 saysWhat is heat stress?And what OSHA requires employers to doThe ratings, test results and standards shown here are the manufacturers' published values, reproduced as published. Nothing on this page is a recommendation by Bayshore Safety that any product is suitable for a particular task, hazard or workplace. Selecting safety products and protective equipment is the responsibility of the end user and the employer, based on their own hazard assessment and the regulations that apply to their work. Confirm every value on the manufacturer's own documentation before use.