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New cedar deck - when to stain?

Hi all,
When is the best time to stain and finish new cedar deck? Which products would you reccomend?
I would like it to be little darker then natural colour of wood and yet gran to be seen. This way it will be seen through the balcony door as a continuation of our beautiful dark ouk old floor in the family room.
So I guess it's transparent stain. But do I do it ASAP or wait untill it ages little bit?

Re: New cedar deck - when to stain?

Depending on your location, sunlight, air flow, ambient air temperatures, rainfall etc, the time it takes for the wood to dry out enough will need to be determined on site. I cannot tell you from here. A moisture meter would be handy.

Re: New cedar deck - when to stain?

For cedar, stain before installation would be great to get color on the edges.

Re: New cedar deck - when to stain?

Traditionally, new cedar decks would be allowed to age for close to a year, this to ensure that the grain had opened up enough to let the stain penetrate deep into the wood. New smooth cedar usually has some degree of "mill glaze" on it. This is caused by the spinning planer blades that made the board smooth. The blades create heat and polish the board, sealing the grain - mill glaze.

To test for the presence of mill glaze, simply pour a little water onto the cedar and watch what happens. If the water beads up and sits on top of the wood for the better part of an hour, you have mill glaze. If the water sheets out and obviously is being drawn into the grain of the wood, you do not have mill glaze.

If you stain over mill glaze, it will look great - until next spring when it will fail! You must get rid of the glaze, either by natural aging, sanding, or by treating with oxalic acid. Oxalic acid is the main ingredient of most deck brighteners.

If you elect to sand, do not use too fine a grit of sandpaper, as it too can cause mill glaze, especially when used on a power sander.

Behr's 2 in 1 Deck Brightener contains oxalic acid. Flood the deck with the properly diluted solution, keeping the deck wet with the solution for at least a half hour. A vigorous scrubbing with a bristle scrub brush will aid in opening the grain. Then rinse off and let dry down.

Aging the deck is the least effort. Cedar is full of oils which will protect it naturally for a long time. It is naturally rot resistant and will not be damaged or even begin to gray in a years time. After the water test shows the mill glaze is no longer present, you can treat the deck with either an oil or water based stain.

Unlike interior stains, which only provide color, exterior decking stains provide both color and sealing protection. You do not need aa extra seal/protection coat over exterior stains.

Generally, the more pigment in a stain, the more protection, as it is the pigments which block the sun's UV rays. All oil stains with which I am familiar, require a yearly maintenance coat. After a few maintenance coats, the color can begin to look somewhat solid or opaque. Cabot's, Penefin, and Sikkens are three brands with which I have had good luck over the years. Cabot's "Clear Solution" will give your deck that great look it has right after the rain has wet it, but clear oil has the least protection from the sun. Stay away from products such as Thompson's Waterseal which is loaded with silicons. The silicon presents problems down the road, as nothing will stick to silicon, including more silicon!

The water soluble stains tend to have longer lives, but when they fail, will probably require that you strip the deck - not fun! They too require maintenance coats, but generally at longer intervals.

Re: New cedar deck - when to stain?

thank you so much for advise. I can see you have a lot of expertise and understanding of the wood. Some of the phenomena you describe I already experienced with my old deck.
And yes, the new one has a shiny surface.. I just didn't know what it's called. Few weeks passed since it was installed and it gets nicer every day... So I will wait for it to age graciously, test for glaze and then stain/seal if it's ready.
Thanks a lot!

Re: New cedar deck - when to stain?

I found this journal article helpful in understanding "Mill Glaze"

Re: New cedar deck - when to stain?

"mill glaze" thats a new one, ive always known it to be called "snipe"

Re: New cedar deck - when to stain?

Let me preface by saying that I don't have a deck, never built one and probably never will. I know next to nothing about the care and feeding of decks. Also, I rarely buy cedar, so I may not be knowledgeable about what portions of the cedar tree are normally sold as cedar lumber.

However, there have been some statements made in this thread that I think should be revisited and clarified. With utmost respect for Ordjen's knowledge and experience, I think the following statements need to be clarified:

1. "Cedar is full of oils which will protect it naturally for a long time. It is naturally rot resistant and will not be damaged or even begin to gray in a years time."

If you have a "cedar deck", you should be aware that ONLY the heartwood of cedar is rot resistant. The heart wood is the generally darker wood closer to the middle of the tree trunk. As the tree grows, chemicals called "extractives" form in the heartwood, and it is these extractives that give the heartwood it's darker colour and it's rot resistance. No extractives form in the sapwood, and so the sapwood of cedar is no more rot resistant than the sapwood of any other tree.

I'd find out whether or not what you have is a deck built entirely of cedar heart wood. If not, the cedar sap wood in your deck is just as susceptible to wood rot as spruce or fir, and you should maintain your deck accordingly. Ditto for Redwood.

Here's some references you might want to read to confirm I'm not just making stuff up:




That last reference shows the degradation caused by exposure of wood to UV light. It seems apparant to me that the sooner you protect the wood from UV light, the better.

2. "Generally, the more pigment in a stain, the more protection, as it is the pigments which block the sun's UV rays. All oil stains with which I am familiar, require a yearly maintenance coat. After a few maintenance coats, the color can begin to look somewhat solid or opaque."

It's true that it's the pigments in wood stains that block the UV light from the Sun, but it's not true that opacity goes hand-in-hand with UV protection.

That's because there are synthetically produced iron oxides ("rusts", basically) which are transparent to visible light, but absorb UV light, and exterior wood stains and automotive clear coats will use these transparent iron oxides as UV blockers to protect the substrate or paint without hiding the substrate or affecting the colour of the paint.

I don't know a lot about transparent iron oxides either, only that they apparantly don't scatter light, and are therefore completely transparent. (How that can happen under our current understanding of the behaviour of light is something I find inexplicable. In fact, the reference cited below doesn't explain how that can happen either, it merely states of these iron oxide pigments that "When fully dispersed, they do not scatter light and are hence completely transparent." Put this in the same bag as UFO's and the Burmuda Triangle... it clearly means that our understanding of light or the way it behaves isn't complete.)

The word "transparent" doesn't necessarily mean colourless, and my understanding is that transparent iron oxide pigments can be both with colour and without, kinda like stained glass and window glass. Apparantly transparent iron oxide pigments are "needle shaped" and can be made into a variety of yellow and red colours by changing the length to width ratio of the needles. These colours compliment the natural colour of wood.

This is a highly technical subject, and anyone wanting more info is referred to this article from "Paint & Coatings Industry", which is a trade publication of the architectural paints and industrial coatings sector of the economy:


Re: New cedar deck - when to stain?


An interesting article on possible reasons for paint/stain failure. I will , however, stick by the water test. If water does not penetrate the surface of the wood, neither will any paint or stain, either water or oil based. If the stain is merely sitting on a slick surface, it will fail in a short time, usually in the spring when the winters' accumulation of moisture wants out of the wood. The vapor pressure within the wood on the first hot day will pop the finish because it has not deeply bonded into the wood.

I don't think it is a bad idea to treat decks that have weathered for several months with an oxalic acid deck cleaner to remove any UV degraded surface cells. The acid will also additionally open the grain.

Decks, due to their very construction, allow water to enter the wood, especially during the long rainy winters here in the Pacific Northwest. There are too many vulnerable places for water to freely enter the wood: decking boards sitting directly on unsealed joists, hundreds of over torqued woodscrews sitting in little craters which hold water, butt joints which are inaccessible after the deck is assembled, undersides of decks which rarely get sealed, etc.

Would we consider building a house without back-priming the wooden siding and caulking all the joints to keep the water out? No way! But we build wooden decks, subject them to severe weather and then wonder why they fail.

I had my choice of building a deck or putting in an exposed aggregate concrete patio when I moved to my house here in Portland. I chose concrete!:) I've re-finished too many wooden decks in my life to want to do this in my old age!

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