Matt is a professional painter and freelance writer, sharing his knowledge, house-painting tips, and product reviews.
Can You Paint Varnished Wood?
Painting varnished wood by hand is really time consuming, but when done correctly, it looks awesome. Most stained interior trim is coated with a protective finish that doesn't bond well with paint. Stained and varnished wood needs to be totally sanded, cleaned, and primed for the best paint adhesion.
Painting stained trim in a home is what this article mostly refers to, but most of the paint prep is the same as painting varnished paneling, furniture, or doors.
Clean the Surface
The surface should be thoroughly cleaned before sanding and priming. You can clean after sanding, but I usually do it before sanding. Most people reach for a de-glossing agent when cleaning, but there's no need to use harsh chemicals that are hazardous to your health. Traces of these chemicals can remain on the surface of the wood, causing fish-eye and bonding issues with paint. Simply use Dawn dish soap to rid the surface of dirt and debris.
Cleaning is not meant to take the place of sanding. Although liquid sanding products, like Klean Strip and Gloss Off, claim to remove gloss without sanding, these products don't work well and leave residue on wood. Cleaning is only meant to remove dirt and grease from the surface. Sanding will break down the gloss for a strong bond with primer.
Sand the Varnish
Sanding definitely sucks, but it's a must when prepping varnished wood for paint. Sanding wood dulls the glossy finish of varnish so the primer and paint sticks well without issues.
For sanding stained base board and frames, I use a brand new 3M sanding sponge. A sanding sponge is very coarse and works well for removing varnish and exposing the raw wood underneath. If you want to use sandpaper, wrapping the paper around a sanding sponge makes it a lot easier to maneuver into corners and along trim edges.
For table tops and larger, flat surfaces, a random orbital sander is the most efficient method for sanding. Load the sander with 180 to 220 grit sandpaper. Use a tack cloth to remove excess sanding dust before priming.
Best Primer for Varnished Wood
When painting over varnished wood, my go-to primer is the oil-base product Cover Stain by Zinsser. Yes, it's oil and it smells horrible, but it seals wood to prevent bleed-through from tannin. Cover Stain is also an excellent bond coat for paint. It dries in one to two hours.
Another excellent option is the shellac primer BIN by Zinsser. This product is very thin and messy to work with when using a brush, but for spraying, it sprays really well and levels nicely over wood. It also dries in 30 minutes and can be top coated in about one hour. Like Cover Stain, it seals wood and bonds really well with paint.
Another primer that can be used to prime varnish is Pro Block by Sherwin Williams, also an oil-base primer. This product also seals wood and provides a bond coat for paint. The smell of this primer is really bad. A respirator and ventilation is a must.
There are latex products that can be used to prime varnished wood, but in my experience, they don't perform as good as oil-base primer. Latex primer won't prevent tannin bleed. Oil primer smells terrible, but it works the best.
Use Protective Masking Paper
Whether you're brushing or spraying primer on interior wood, it's very messy. A brush stroke will fling sprinkles of primer all over flooring, which is hard to remove if it dries. When painting trim, the flooring beneath the substrate should be covered with tape and masking paper.
The easiest way to mask flooring next to base board and door frames is with a 3M hand masker. You simply equip the masker with tape and a roll of masking paper and the machine simultaneously attaches both to the floor in one pass. This not only protects the floor, but it also allows base board to be painted quickly without having to carefully cut-in.
Painting Over Stained Wood
After the surface has been cleaned, sanded, and primed using an oil-base primer, the wood should be lightly sanded and then painted. Painting stained wood usually takes at least three coats of paint after one coat of primer.
The two products I use the most for painting wood trim, frames, cabinets and furniture is Pro Classic and Emerald urethane enamel from Sherwin Williams. I like the semi-gloss finish. This paint contains levelers that allow it to level evenly over a surface when sprayed or applied with a brush. The re-coat time is about four hours. For painting trim, a 2 1/2-inch angled brush is a good size.
If you're faced with the task of painting all the stained trim in your house, you should consider using an airless sprayer instead of doing it by hand. Spraying the wood will easily cut the time in half and look better. It's very tedious work, but if you take the time to do the job correctly, the paint will be very durable and look amazing.
Painting vs. Replacing
In the case of painting stained trim, hiring a painter is cheaper than hiring a carpenter to replace the wood with paint-ready trim. The downside to painting stained trim white is that it shows dirt more than stain does. Glossy paint also makes damaged wood and imperfections more noticeable.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Question: I purchased all new doors for the interior of my house, primed then with oil-based enamel primer, then painted then with oil-based enamel. Can I use the same products to paint over the varnished molding that is between the ceilings and walls? I'm trying to avoid sanding and as much prep work as possible.
Answer: The wood should be sanded and oil primed before painting.
Question: I am painting over my varnished trim and will be sanding it all first. Could I use a paint that already has the primer mixed in?
Answer: No. Paint and primer in one is not a primer sealer. The paint is thicker to help with coverage, but it won't seal the surface of your varnished wood. Use oil-based primer sealer. I like the product Cover Stain. This primer provides an excellent bond coat for paint.
Question: I want to paint a wall of built-in cabinets and drawers (built in the 1950s, knotty pine, so I assume varnished). If I rent a sprayer, will I be able to paint the sliding cabinet doors without taking them down? I think I can remove the drawers to place horizontally, but so far I do not see how to get the doors out.
Answer: You can paint sliding cabinet doors, but if there's too much friction between the doors and the wood around it, the paint can mar, or rub off, when opening and closing them.
Doors can be spray painted very easily without taking them down, but the hardware needs to be protected from over-spray.
Question: I want to paint oak stair posts. You mention that the Pro Classic Sherwin Williams paint has levelers. Does that work on a vertical surface like I am intending or only on a horizontal surface?. BTW- Thanks for the warnings against liquid sandpaper and latex primer. I was originally planning to use both.
Answer: Yes, Sherwin Williams Pro Classic acrylic is a leveling enamel that works great on vertical and horizontal surfaces. On vertical surfaces, you have to be more careful not to apply the paint too heavy otherwise it will drip, but with just the right thickness, the enamel lays out really nice. I've painted many staircase posts and spindles with Pro Classic. It's a good product. It's a little tricky to work with at first, until you get a feel for it. The enamel starts to set up fairly fast so you have to brush it on quickly. The enamel sprays really nice too if you decide to go that route. Use oil-based primer on the posts.
© 2017 Matt G.
John mccaffery on October 10, 2018:
Want to paint glass panelled mahogany stained &varnished doors white