Deck Finishing Procedure and Products

If you have cleaned your deck thoroughly, finishing is the next step.

Proper deck finishing must begin with preparing the deck surface.

In order for finish, stain or sealant to adhere properly, the best thing you can do is take an orbital hand sander and lightly sand the surface with an 80 grit paper. This prepares the wood surface perfectly for the stain or finish.

With the orbital sander it could add another 30-40 minutes to your day but prolong the finish another year or two.

So sanding is well recommended.

Apply a Surface Finishing Coat

After the deck boards have had a few days of warm weather to dry out you can apply your finish coat.

This is important. If the deck boards are still moist the finish coat will not adhere properly.

To apply your finish use the garden sprayer again and take care to avoid overspray near the sides of the house - or use a flat brush that kind of pushes the finish or rubs it onto the material.  A roller can often overload the deck with too much finish.  It is a thin coat you are after.

What Type of Deck Finishing Product Should You Use?

That is an excellent question because there are 3 commonly used types of deck finishes.

Each one has its unique characteristics and you should be aware of them in order to choose the right finish for your deck.

Clear Finish

A clear sealer for wood deck surfaces

These products go on clear and add minimal to no coloration to the wood.

They typically contain only a water repellant and sometimes preservatives. They don't usually last as long as an alkyd stain that penetrates the wood.

Some clear finishes however are also penetrating as they contain oils and are absorbed into the wood providing a longer lasting finish.

This example is from Sherwin-Williams but there are many other good products from other manufacturers also.

Semi-Transparent (alkyd stains)

A semi transparent oil based stain

These are also known as penetrating finishes because they are more opaque in color and the grain is still visible.

This is a good example of semi transparent stain from Sherwin-Williams.

They actually soak into the wood so never peel off - supposedly. They eventually just fade and then it's time to re-apply. Lots of companies make similar high quality products. However, each product can be different.

The most important recommendation is to avoid applying under direct sunlight as the surface gets quite hot and this can cause problems with proper adhesion.  Secondly, do not use a roller.  Use one of those flat brushes and this lets you apply it in a very thin coat.  Thinner coats are much better and less likely to bubble up and peel off.

Solid Stain or Paint

A solid stain product

This kind of finish sits on top of the deck surface and has pigment for color.

Here is a Sherwin-Williams product that is representative of the solid stain category. Solid stains or paint do not withstand the wear and tear place on horizontal surfaces very well so they are not recommended for decks unless you are prepared to re-apply them annually.

They tend to crack and peel and are best suited for siding or fences rather then deck finishes.

Deck Finishes Contain Some or all of These Ingredients

Every finishing product is made up of one or a combintation of the following compounds.

Oils, Parrafins and Resins

Oils or parrafins repel water and are mixed with an agent to spread the finish. Thompsons Water seal is a good example of a parrafin based coating. But it requires a bi-annual application to really be effective.

Oils also repel water but soak into the wood deeply so last longer.

Resins are longer lasting and more expensive. The nice thing about resin finishes is they don't harden like a varnish but actually soak into the wood. They are also known as alkyd resin.

Preservatives

Some finishes also contain preservatives to prevent mildew and mold from forming. This is a great quality especially if you live in an area subject to a lot of rain or moisture.

UV Inhibitors

UV inhibitors provide protection against the rays of the sun and are designed to prevent or slow the discoloration process of exposed wood.

Hopefully this explanation has answered all of your questions about deck finishing so get out there and make your deck look great!

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