Varnish must properly cover the entire surface with enough coats before it can protect a surface. So, how many coats of varnish do you need?
For high-traffic or busy surfaces, you need 3 coats of varnish for maximum protection and durability. For low-traffic or decor surfaces, 1-2 coats are enough.
Applying too many coats will make the finish sticky because the solvent can’t evaporate. On the other hand, if you don’t apply enough coats, varnish won’t properly cover a surface and protect it.
Why Does it Matter?
The number of coats matters because it determines the varnish’s durability, type, and quality. If you don’t apply enough coats, the finish won’t be strong enough to protect the surface.
Also, the finish will be thin, offer little to no protection, and chip and peel faster. Since the finish is thin, it takes less effort to dent or damage it, and water can penetrate it easier. The minimum number of coats for varnish is 1.
The varnish will turn sticky and won’t dry as it should if you apply too many coats. When the varnish is sticky, it absorbs (attracts) dust and stains, making your finish dark and filthy.
The maximum number of coats for varnish is 5. If you exceed this number, the finish won’t become more durable or strong. Instead, the finish will become too thick and peel off because it can’t dry properly. Also, since varnish is a clear coat (no color), the finish will become too blurry.
You Need Another Coat If:
To know if you need another coat, inspect the finish. For example, if the first coat looks light and doesn’t cover the surface properly, you need another one. On the other hand, if the first coat covers the entire surface and has a thick layer over it, you don’t need another coat.
The type of surface also determines if you need another coat or not. You need more coats for busy surfaces exposed to constant handling or water. You don’t need another coat for low-traffic surfaces that aren’t exposed to water.
The more coats you add, the thicker and more rigid the finish becomes, and the more it protects the surface underneath. However, the finish won’t become more durable if you exceed the coat number limit (5).
However, water-based or acrylic varnish usually requires two or more coats. That’s because the finish isn’t strong enough to only protect the surface with one coat. On the other hand, oil-based varnish is thicker and offers more coverage, so you don’t need too many coats.
Different Types of Varnish:
You need 2 coats of yacht varnish for low-traffic surfaces and 3 coats for exterior surfaces or boats. Ronseal, a popular manufacturer of this sealant, advises applying 2-4 coats.
This is one of the most durable types of varnishes. It’s designed to be used on wooden parts of boats, yachts and ships to protect the wood from water damage. Because of its durability, this sealant is used on different exterior surfaces.
Since spar varnish is too thick, you only need 2-3 coats of it. However, you shouldn’t go above 3 coats because the finish will be too thick and won’t dry. Optionally, you can thin it with mineral spirits before applying.
Gamvar is a solvent-based varnish that only needs 1-2 coats for proper coverage and protection. That’s because this sealant takes too long to dry, and the more coats you add, the longer you must wait. It’s also advised to thin it and only use a paintbrush to apply thin coats.
You must apply up to 3 coats of floor varnish. That’s because floors are exposed to constant foot traffic and furniture weight, so the finish needs more durability and protection.
Depending on the brand, you need 2-3 light coats of spray varnish.
Different Types of Surfaces:
You need 1-3 coats of varnish on a wooden surface. However, the number of coats depends on the type of wood and varnish. For instance, you need 3 coats of water-based varnish while only one coat of oil-based varnish.
Also, for wooden surfaces exposed to heavy traffic and weights, you need 3 coats. For decor wooden surfaces, you only need one coat.
Since oil paintings won’t get used or touched, you only need one coat of varnish. One coat is enough to protect the painting from small elements. Also, if you apply too many coats, it will affect the painting’s quality and colors.
On the bare wood of boats, you need 5 coats of spar marine varnish for proper coverage and protection. That’s because boats are exposed to constant water and need more water protection. You need 3-4 coats for boats with an existing finish.
On outdoor furniture, you need 3 coats of exterior varnish. That’s because outdoor furniture is exposed to weather elements, such as rain and wind, and needs more protection.
You need 3 coats of varnish over different types of paints. That’s because paints don’t have protective additives and will get washed off if exposed to water. So, you must apply varnish over paints to protect them from moisture, water, scratches, and other damage.
You need 3 coats of floor varnish for the stairs. That’s because stairs are a high-traffic area and need more protection.
In summary, the number of varnish coats depends on the surface type. However, 3 coats are the universal standard for most surfaces. The maximum number of coats for varnish is 5, while the minimum is 1.
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,