Deck Staining Problems and Solutions

Staining a deck can enhance its appearance and protect the wood, but several common problems can arise during or after the process. Below, I’ll outline the most frequent deck staining issues—peeling, fading, uneven color, and mold/mildew growth—along with their causes and practical solutions.

Peeling Stain

Problem: The stain starts to peel or flake off, leaving the deck looking patchy and exposing the wood.
Causes:

The deck wasn’t properly cleaned or dried before staining, allowing dirt, moisture, or old stain to interfere with adhesion.

The wrong type of stain was used (e.g., a film-forming stain on wood that expands and contracts a lot).

We typically see a combination of a previous stain or clear interfering with the next stain system installed. I've never seen a new deck stain system fail, it's always on the second go around with installing a different product. So the first tip is to always use the same stain system or completely strip, remove or replace. It just isn't worth the hassle.

Solutions:

Strip the Old Stain: Use a deck stripper or sandpaper to remove all peeling stain. This maybe very complicated based on the configuration of your deck, but as a professional, we are set up to spray eco friendly strippers and wash off to remove and neutralize.

Clean Thoroughly: Wash the deck with a deck cleaner or a mild bleach solution to remove dirt and debris, then rinse well.

Dry Completely: Wait 24–48 hours (depending on weather) to ensure the wood is fully dry.

There are waterborne systems that can be installed while the wood is wet, there are only a few systems available, however we strongly recommend only using solvent borne systems above the snowline or in freezing temperatures. So this is location dependent.

Restain: Apply a stain suited to your wood type (e.g., penetrating oil-based stains work well for most decks).

Fading Color

Problem: The stain loses its vibrancy quickly, making the deck look washed out.
Causes:

Prolonged exposure to sunlight and weather breaks down the stain’s pigments.

A low-quality stain without UV protection was used.

Solutions:

Choose a UV-Protective Stain: Opt for a high-quality stain with built-in UV inhibitors to shield against sun damage.

Maintain Regularly: Reapply a clear top coat or a fresh layer of stain every 1–2 years to preserve the color.

Clean First: Before restaining, clean the deck to remove dirt and faded residue.

Uneven Color

Problem: The deck has splotchy or inconsistent coloring after staining.
Causes:

The stain wasn’t stirred properly, leading to uneven pigment distribution.

Application was rushed or inconsistent (e.g., too much stain in some areas, too little in others).

Insufficient drying time between coats caused overlapping patches.

Solutions:

Sand the Surface: Lightly sand the uneven areas to smooth out the finish.

Stir Thoroughly: Mix the stain well before and during application to ensure consistent color.

Apply Evenly: Use a brush, roller, or sprayer, working in small sections and maintaining a wet edge to avoid overlap marks.

Allow Proper Drying: Wait the recommended time (usually 4–24 hours) between coats, per the stain’s instructions.

4. Mold and Mildew Growth

Problem: Dark spots or fuzzy growth appear on the deck, especially in damp or shaded areas.
Causes:

The deck stays wet for long periods, encouraging mold and mildew.
The stain lacks anti-mildew properties.

Solutions:

Clean the Deck: Use a mildew remover or a solution of water and bleach (1:3 ratio) to scrub away mold. Rinse thoroughly and let it dry.
Choose a Resistant Stain: Apply a stain with mildew-resistant additives.
Improve Conditions: Trim nearby plants for better airflow and sunlight, and ensure proper drainage to keep the deck dry.

Tips for Success
Preparation Is Key: Always clean, sand, and dry the deck before staining to ensure the best results. Different woods (e.g., cedar, pressure-treated pine) may need specific prep or stain types, so check what’s best for yours.
Pick the Right Product: Match the stain to your climate and wood type—oil-based stains penetrate well, while water-based ones are easier to clean up.
If you don't know the history of the deck, test a sample a few weeks in advance to the total application to see if the deck has an interaction to the stain. Something like Thompsons waterproof sealer makes staining a deck with something else impossilble.
Take Your Time: Rushing leads to mistakes like peeling or uneven color. Follow drying times and apply in mild weather (50–80°F, low humidity).