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How to Remove Thompson Water Seal From Wood

how to remove thompson water seal

Removing Thompson Water Seat From Wood

Installing a deck is one of the better investments a homeowner can make. It expands your usable square footage, improves quality of living, boosts exterior aesthetics, and makes your property more valuable. For all those benefits, a deck does require a lot of maintenance – especially wood ones.

Part of regular wood deck maintenance involves sealing the surface every 1-3 years. A product such as Thompson Water Seal creates a protective barrier between your deck and all the elements that can harm it such as moisture, UV rays, mold, and insects.

The slippery slope about wood sealants is that the very purpose of the product is to not let anything penetrate the sub-surface. Therefore UV rays and moisture won’t harm the deck boards, but at the same time you won’t be able to paint or re-stain a sealed surface. At times, it does come in handy to know how to remove Thompson Water Seal from wood.

What Does Thompsons Water Seal Do?

There’s nothing quite like the aesthetics of wood grain in home construction. There’s a reason why products like vinyl siding or laminate flooring are now being manufactured to give the appearance of wood. For all the natural curb appeal benefits that wood provides, it is also a very vulnerable product.

Untreated wood is porous, therefore it will soak up water which will eventually destroy the structural integrity of the product and cause it to rot. For safety reasons, and to get the maximum life span from your investment this wood should be protected with a water seal.

A protective coating is nothing new for wood products around the house. Wood flooring, window trim, baseboard, and crown molding will often be topped off with a layer of clear polyurethane so that the wood grains sparkle through a dazzling shine. The main job of polyurethane though is to protect the surface against scratches, heat, and oil/grease/water penetration.

Polyurethane has interior uses, because (hopefully) the moisture exposure for crown molding, doors, and baseboard is minimal. Thompson’s Water Seal is formulated for exterior use because rain, snow, and UV rays are a constant presence on decks. It should be noted that water sealant can be used on all types of exterior wood besides decks, features such as gazebos, pergolas, garden wells, etc.

What is Sealant Made Of – How Does It Work?

Before you tackle the task of how to remove Thompson Water Seal from wood, it also never hurts to know what the ingredients for the substance are and how they work. These sealants are water based, and the main components are denatured alcohol and wax. The denatured alcohol has penetrating properties, and the wax is the force field that obstructs the water.

That’s the basic properties of how a sealant works – it penetrates the wood surface and hardens up the materials inside the wood. Knowing that is important in figuring out how to remove water sealant from wood.

How to Remove Thompson Water Seal From Wood

The fact that Thompson’s Water Seal penetrates the wood and doesn’t just coat the surface makes it a bit harder to remove. Before getting to that point however, here are some reasons why homeowners would want to remove the seal:

  • Want to paint or stain the deck a different color
  • First installation was done improperly (sticky, bubbles, streaks)
  • Used an inferior product that isn’t working (deck rot)
  • Removing and Repurposing deck boards for other projects (end tables, planter boxes, accent walls)

Method #1: Use a Deck Stripper

The first method to try and remove the water seal is to use a deck stripper. Stripping is required when changing the opacity (changing to a semi-transparent from a solid color), but the good news is that the process is rather simple.

Deck strippers are applied to neutralize clear sealers as well as semi-transparent and transparent stains. They are brushed or sprayed on, allowed to soak for 15-20 minutes, and then sprayed back off. This should restore the natural wood colors to the deck.

Method #2: Sanding

The other way to try and remove stains and sealers from a deck is by sanding the surface. Sanding is a more labor intensive process, and it’s important to do the job properly so as to not ruin the integrity of the boards. 

Using sandpaper grit rougher than 60 or 80 for example can close the pores of the wood and it won’t absorb the new stain as well.Sanding unevenly will also create dips in the deck that may hold rainwater. 

Remove Thompson Water Seal From Wood: Tips and Summary

Remember that removing old seal and re-staining is done for cosmetic/ protective purposes. New stain is not going to strengthen rotting boards, which should be replaced.

Another tip to remember is that all the old seal will need to be removed prior to re-staining, otherwise you’ll have blotches and patches of different colors. You’ll likely have to use the deck stripper as well as some sanding in tough-to-remove spots.

Another product you should apply prior to the new stain is a wood brightener. This product is applied to the deck after it is stripped of the old sealer, and is used to lower the PH of the boards. This opens up the pores and helps the new stain or sealant absorb better.

We apply water seal with the intention that it will never need to be removed, only reapplied every couple years when nature takes its toll. Just know that if the water sealer does need to be removed – it can be. 

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