Why is my deck stain peeling?

Why is my deck stain peeling and how do I prevent this from happening? This a common question and occurrence for many exterior wood deck owners. Homeowners love their wood decks and patios and nothing ruins the outdoor experience more than an ugly looking peeling deck. In this article, we will look at the main reasons for deck stains failures, how to fix them, and how to prevent the stains from peeling in the future.

Did Not Prep the Deck Properly:

Improper prepping of the deck is the number one reason that a new decking stain will fail. In general, the better a deck stain penetrates into the wood the better it will perform. Here are a few examples of improper prepping.

  • Grayed deck was not cleaned with a wood deck cleaner prior to application of finish. The use of a quality deck cleaner will not only remove all the dirt, grime, and graying but it will make the prepping process much easier. Never use household bleach or chlorine based deck cleaners. This will damage the cellular structure.
  • Old failed coatings were not removed with a deck stain stripper. You should not apply a new coating over top of an old coating that has failed by peeling or wearing unevenly. This will prevent you new coating from performing properly as it will be subjective to the continual failure of the old stain.
  • The use of a wood brightener was not used after a deck cleaner or stain stripper. It is very important to use a brightener to neutralize the caustics of a cleaner or stripper. Failure to use a deck brightener will leave the wood in a high pH state. Decking stains will fail faster if the wood has a high pH balance.
  • Applying a water-based stain over top of an oil-based stain or vice versa. Many stains will not adhere to different brands or types of stains. If switching a brand or type of stain it is best to remove the previous coating as much as possible. This will give your new coating the ability to adhere and penetrate into the cellular structure.

Deck Sanding:

Sanding the deck to a super smooth surface such as a hardwood floor causes penetration issues. Wood decks are not the same as interior wood. The more porous the wood is the better the stain can attach to the interior of the wood. If you sand we strongly suggest that you sand with paper of 60 grit or less. In addition, it would be best to use a deck cleaner and brightener to remove the sand dust when done.

Wrong Type of Stain or Sealer Was Used:

Always use stains and coatings that re specifically designed for exterior wood decks. Coatings that are too thick or unable to penetrate the wood will fail much faster and will be difficult to fix in the future:

  • Never apply a polyurethane or varnish type coating to horizontal wood. It will peel, turn yellow, and will require heavy sanding to fix.
  • Interior stains such as Minwax will not work on outside decking. They will be prone to mold and mildew while offering zero UV protection
  • Exotic hardwoods such as IPE require coatings that are able to penetrate into their very dense cellular structure. Make sure to buy a brand of stain that is specifically designed for these wood types.

New Decks:

Just because a deck is new and free of dirt and old coatings does not mean it is ready to be stained. All new decking should be prepped to remove the mill glaze. This allows the stain to penetrate. This can be accomplished with a deck cleaner and deck brightener.

More Stain is Better:

Very common mistake here. Homeowners believe that if they apply another coating or two that the stains performance will increase. It is actually the exact opposite or less is better. In general, you want to apply as much stain as the deck allows to absorb into the wood. Coatings that are over applied will film “on top” of the surface instead of “in” the surface. Film forming coatings are much more prone to peeling and wearing.

Poor Quality Brand of Decking Stain:

There are many deck stains available today but one thing is certain, they are not all created equal. Do some research online for deck stain and reviews. You will find that many of the different stains brands have a history of failure and poor performance. Do not believe ridiculous deck warranties either. The best deck stains are typically not bought at your local Big Box store but rather online or at your higher end specialty stores and lumber yards.

Penetrating vs. Film Forming Stains:

Penetrating stains will always outperform stains that dry or “film” on top of the wood. In general, the better the deck finish penetrates, the better the performance. Many stains claim to penetrate when they actually do not, Be wary of water-based semi-transparent acrylic wood stains such as Behr and Sherwin Williams. They claim to penetrate when in actuality they are thin versions of paint.

Best Practises for Deck Stain Performance:

  • The better you prep the deck, the better a stain will perform. Do not skip steps and strongly consider stripping off old coatings first prior to reapplication.
  • Penetration is king! The better the stain penetrates into the wood the less chance of peeling and wearing
  • Do not over apply!
  • Read all manufacturer’s application directions.
  • Research the brands of stains thoroughly.
  • Choose a deck finish that allows ease of reapplication in the future. All stains fail eventually and choosing a coating that requires minimal prepping for reapplication makes future maintenance much easier!

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