Double Staining = Double Trouble

Have you ever finished staining your floor and wished you chose a darker finish? Double Staining is a common practice by homeowners, however; most homeowners don’t know that a second coat of stain will frequently cause the top coat to peel. Another variation of this problem is applying a coat of stain over the first sealer coat causing a failure point in the system.

double stainingMany may wonder, “What’s the big deal? It’s just another layer of stain.” The problem is that most oil based stains contain color pigments, dyes and a very small amount of binder. The first coat is thin enough for the top coat or sealer to penetrate and bond to the wood fiber. If a second coat is applied, it builds the thickness and two things happen. First, the sealer or top coat cannot penetrate through the stain to grab the wood fiber. This causes the second issue, the bond now relies on the strength of the stain to bond the surface coats to the wood. Most stains do not have enough internal strength to hold the entire film surface together and this can cause peeling of the finish. If there is finish on the floor and finish on the back of the film, there is not enough stain strength to hold the two surfaces together.

One way to prevent this is to apply the stain to multiple sample pieces of the same type of wood. If the overall color is not dark enough, use a darker stain on the floor. If the color is right, but not intense enough, water pop the grain of the raw wood after screening to add to the color load. An alternative method is to finish the screening with a courser screen than normal.  You can also use an acceptable dye, of the color of stain, on the raw wood first to add more color.  Since dyes have no binders, multiple coats can be applied before staining.

If you’re looking to repair your stained floor:

  • If the color isn’t right, it will have to come off and be redone.
  • If the color is merely uneven, a small amount of similar dye color added to the sealer and/or top coat will even out the job. Adding dye to the sealer and finish coats can also help give a slightly darker color look. You can contact Basic Coatings® regarding questions about this.

Micah Petersen, Senior Product Manager for Basic Coatings®, spent the first 15 years of his career as a Research and Development Chemist before becoming Product Manager. In his free time he enjoys spending time with his family and a multitude of outdoor activities. For further questions regarding hardwood floor care and Basic Coatings, please email Micah at Micahblog@basiccoatings.com.

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