Old stain does not need to be completely removed from a deck in order to apply a new coat of stain under most circumstances. In this article, we will cover what should be removed from a deck for a new coat, why some old stain is a nonissue, why you may want to completely strip a deck, and the basics of deck prep and stain removal.
What should be removed before staining an old deck
Any old, flaking, or bubbling stain should be removed from a deck prior to an additional coat being applied. Under most circumstances, this will not be the entire coating and just areas that dealt with additional wear over time. A perfectly prepped deck could have 10% of the old coating removed or 90% removed and it will entirely depend on the adhesion of the existing product to make that determination.
To determine how much old stain should be removed, run a scraper across the surface of the deck. If nothing comes up and there is no visual indication of peeling, it is likely just fine. If stain comes up, keep scraping until you remove the flaking areas completely.
“As long as the deck is cleaned of organic growth, it is not always necessary to remove all of the stain before adding another coat” - Nicholas Flemion, Central Virginia Power Wash
Why some old deck stain on the surface is a nonissue
As long as you are using a similar product to what was already on the deck, having bits of stain that are stuck into the wood underneath the new stain is a great thing. It provides an additional layer of protection from the elements and it will be there when the new top coat peels away.
Stain wears not based on age but on exposure to the elements. When old stain that is properly adhered to the wood is covered, it will not continue to weather and will remain perfectly intact over the years until it is exposed again. This extra layer is a benefit to you and your deck and should be kept if possible. If the stain won't budge, do not force it.
For help picking the right stain for you, read our article What Type of Deck Stain is the Best.
Why you may want to completely strip your deck
If you are using a different stain transparency or want to start fresh on your deck, complete removal may be the right option for you. Deck stains come in different transparencies from clear to solid and moving down a transparency is not possible if the existing stain is still on the deck, as it will show through.
If your deck is very old and has many layers of built-up stain, it is completely understandable why total removal would be the right option for you. However, this will be quite expensive as it can take multiple days, a variety of chemicals, and multiple removal methods to completely strip a deck while preserving the underlying wood.
The basics of deck prep and stain removal
To prep a deck for staining and remove only the required stain, follow these general steps:
Pressure wash the surface to remove algae, mold, mildew, dirt, and flaking stain
Hand scrape (if needed) to remove flaking stain
Lightly sand (if needed) the areas immediately surrounding the removed stain
For more info on deck prep, read our article on Deck Washing here.
To completely remove the old stain, follow these general steps:
Apply a chemical stain stripping agent to the stain according to the manufacturer's instructions
Pressure wash off the residue
Repeat these steps if needed
If chemical stripping will not work, which is common, try this process:
Rent a floor drum sander
Sand with 20 grit until complete removal
Pressure wash the surface to unclog the wood's pores before staining
When it comes to removing old stain, more is not always better. If complete removal can be avoided for your project, do not attempt it and just remove the flaking areas.
At EcoWash, we can tackle these projects and would be happy to assist in your deck staining project. If you need help with deck staining, get in touch with an EcoWash representative today.
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