Is It Bad To Leave Your Deck & Fence Wood Unfinished? (Mill Glaze Explained)
You’ve got new wood and you want to protect your investment. But you’ve heard horror stories of peeling decks and dread the thought of endless maintenance. Perhaps you even like the faded gray look. What are your options? Can it be possible to leave your newly built wood deck, fence, or siding entirely unfinished… Forever?
Here’s a quick dive into the pros and cons of unfinished wood followed by an explanation of mill glaze and what you need to know about the first time finishing wood.
PROS of Unfinished Wood
low maintenance compared to sanding / staining / sealing
washing as needed, spring clean, fall, etc.
natural silvery patina over time
deck floor and horizontals will turn fully gray within a year or two
verticals will take longer (depending on sun exposure, etc.)
cedar can still last very long without maintenance
cedar wood will last for 25-30 for vertical applications (fences, siding)
roughly 20-25 years for horizontal (floors, steps), depending on the elements, etc.
CONS of Unfinished Wood
some maintenance still needed to prevent black mold / green mildew etc.
being outdoors, basic washing is still needed like composite and PVC decks / fences
with no pigmented finish, wood will return to gray quickly after cleaning / brightening
many do not like the graying wood look
may look like unmaintained or not cared for
selling a home may be more difficult if buyer perceives gray deck as not cared for
may not last as long without stain/sealer
protective products help with the longevity of the wood
without a pigmented stain & sealer to protect against UV rays, the wood will dry out and crack quicker
What Is Mill Glaze?
If you decide to go the finishing route, it’s important you are aware of mill glaze and what that means for your first time finishing the wood.
Mill glaze is the shiny almost wax like layer as a result of processing at a sawmill. It comes from the knives cutting so quickly that it melts the sugar and cellulose elements of the wood, sealing it shut. You know any lumber will have this mill glaze sheen if it is smooth (versus ‘rough lumber.’)
Mill glaze stays part of the wood indefinitely until it is sanded off. This means that the first time smooth wood is to be finished it must be sanded to open the pores for any stain to penetrate the wood properly opposed to sitting on top. This is crucial for the first time the wood gets finished whether it’s brand new or even several years old.
Quick Points About Mill Glaze
Mill glaze needs to be sanded off before the first time finishing with stain or sealer
Rough lumber does not need to be sanded before finishing
We do not recommend sanding pressure treated lumber. Click here if you have pressure treated wood.
For more details about finishing wood so it never peels, check out our flagship Sand & Stain System in detail.
New For 2021 In Ottawa
Attn: Ottawa Homeowners & Contractors…
Starting in the 2021 season, we are offering pre-finishing for our clients in the Ottawa area. This is for wood profiles such as: decking, fences, siding, pergolas, etc. and consists of removing mill glaze and staining before installation phase to save our clients time and money.
Photo taken from our finishing shop featuring charred wood from charclad, our sister company in Ottawa.
So whether you’ve recently built a deck or fence, or purchased a home that came with unfinished wood, you will need to sand it before finishing it—unless you decide to leave it unfinished entirely now that you know the pros and cons of each.
If you moved into a new house with gray wood and you are unsure if the mill glaze has been sanded off already, you should sand it again to be on the safe side knowing that your oil stain will be able to easily penetrate the surface. After the first sanding and with proper care, it may never have to be sanded again in the future.
