Mill Glaze on Decking and How to Remove It

What is Mill Glaze and How To Remove It

When building a new deck or fence or even using new wood for repairs, it is important to know that wood will not stay new for long. Over time, as the wood is exposed to the sun, rain and other elements, it quickly turns gray and softens. If you want to protect your wood and give it a longer life, it will need to be seasoned, cleaned and protected with a wood stain – solid or transparent; the darker the more protection.

We realize the debate of whether new decking should be cleaned prior to staining. But don’t let the new look and cleanliness fool you, new decking does need to be cleaned before any staining or sealing takes place.

Why does new decking need to be cleaned?

New decking should be properly cleaned primarily to remove any possible mill glaze from the lumber mill.

Ever notice the glossy like film on new wood? That is mill glaze.

Mill glaze develops on milled lumber during production. As the lumber gets cut, the metal blades on the saws and planers get hot from to the friction of cutting the wood. The high temperatures from the blades cause sugars in the wood form a glaze on the surface. This mill glaze is present in the majority of pressure treated pine and cedar lumber you see today. Pine and cedar are also the most common wood used for most wood decks and wood fencing.

What if the mill glaze is not removed?

If your new wood is not cleaned in order to remove any mill glaze, it will prevent any type of deck stain or sealer from bonding and penetrate the wood. The result? Flaking, peeling and premature failure of the stain within the first year.

There have been times when we bid an Indianapolis deck staining project and the customer chooses another contractor. Too often, the customer simply looks at the dollar amount of each bid and goes with the cheaper price. Fair enough. However, a year after that project, we sometimes receive a call from that customer out of the blue about re-staining their deck. They learned contractor they used did not properly prep the wood before applying the stain and the entire deck needs to be redone a year later due to peeling and flaking.

We will gladly help the homeowner and re-stain the deck, but now they’re paying for the same job twice because it wasn’t properly done the first time. It’s fine to go with a cheaper price, as long as you know exactly what you’re getting for your money. The last thing most homeowners want to do is pay for staining their deck twice within a year because it wasn’t done correctly the first time.

How to remove mill glaze

To remove the mill glaze, you will need to use a wood deck cleaner/stripper followed by a light pressure washing. Sometimes scrubbing the wood with a stiff bristle brush is necessary before the pressure washing.

After the wood stripper has been applied, scrubbed and pressure washed, apply a wood brightener. This will allow the wood pores to open up and the stain to penetrate the wood as it was intended.

Applying the stripper and brighter is necessary, even after allowing the wood to season naturally before staining. This process will ensure that even after the wood naturally seasons the wood stain bonds properly. Allow the wood the dry out before anything else to the wood.

Once the wood is dried out sometimes you’ll find a fuzzy residue on the wood. That’s normal. You will probably need to simply go over the decking with a light sanding to remove the fuzz and any remnants of mill glaze that was missed during the cleaning process.

After the wood is dry, prepped and ready, apply your choice of stain. We recommend going with quality oil based stain because it will protect the wood best and provide a longer life.

Common Questions

Will a light pressure wash remove mill glaze?

No. A high PSI pressure wash could, but it could damage the wood in the process.

What if I simply allow the wood to season for a year before staining?

Over time mill glaze will wear off. However, by the time it does wear off and your wood is good and seasoned the wood will still need to be cleaned with a deck cleaner/stripper followed by a brightener. Why? Air pollutants, pollen, dust, mildew, mold spores, etc. can accumulate on the wood over time and will need to be removed before any staining.

Closing Thought

At the end of the day, you’re really better off in any situation to properly clean and prep the wood before applying any stain if you want it to last.

If you’re looking for a good deck staining company to stain your new neck or re-stain and older deck, consider using Legacy Painting for your project.