Redwood Deck

hello guys,

did a redwood deck last week, the first i've done since three years ago. It looked absolutely beautiful when i left it. Guy called me back and said it had white spots on it. Went out there and he was right. It still looked good except where there were knots and grain-pattern changes. They looked white. Is there something I did wrong, or something different that must be done to redwood?? and more importantly, what can be done to fix it?? by the way, all preparation on the deck was done correctly, deck was plenty dry, didn't rain after I left. Would really appreciate some insight here, I don't see many redwood and cedar decks.

thanks guys,

Jon Fife

Cedar and Redwood

Just a thought -

Cedar and redwood tend to need a lot more rinsing, especially where the knots are. They really soak up the cleaner. If you use a cleaner or stripper it is a good idea to rinse extra long on these decks then when you have rinsed it good enough, go back and rinse again!

When rinsing, if you see a white plume in your water (especially near knots) that is a good indicator that you have residual cleaner still in the wood.

Hope this helps

Best of Luck

Russell Cissell

Jon,

What type of sealer did you use? Sometimes, esp on cedar and as well with redwood, the knots will be white for a few weeks. This is the hardest part of the wood and will take a while to "set up". I have had a few of these surface on cedar and kept an eye on them and eventually they did set up and only had to re-apply sealer on a few spots. I totally agree with what Rus said, knots in particular really need to be rinsed. It is amazing how much "stuff" they can hold.

Anyone have a suggestion on sealing a gazebo 25' in the air?

reedster

25 foot high Gazebo

Don't fall!

Older cedar and redwood(even pressure treated) decks the Knots can be very porous,A trick I learned is to spot spray the knots and let them sit a while,don't let the sealer completely dry to avoid lap or spot marks.When you seal the floor the knots don't turn white.You can sit there and spray sealer at a knot for ever and it seems it never stops sucking it up.If you spot spray the sealer prevents the forever thirsty effect and helps the color stay near the surface.

Hello Guys and Dolls,

Have read the above posts and really have to disagree on knots being porous and sucking up the product. I believe you'll find that the knots themselves are a very hard material which contain more resins than any other part of the tree. Knots are generally the last thing to rot out due to the amount of resions they contain. Because of these natural resions, the knots will not take a finish very well.

There are several companies that grind up the knots and use them for resions in producing natural finishes.

The area surounding the knots are a different story. The wood fibers are tight and somtimes they will go in all different directions making penatration of a finish difficult. These areas sometimes need extra back brushing to force the finish into the wood.

When you see a knot missing from a board, it's not because the knot shrunk, it's because the board dried out causing the wood around it to open up and letting the knot drop out.

Take a hammer and beat on a piece of board then take a knot and beat it with a hammer and see the difference for yourself.

Jim Bilyeu
Exterior Woodcare

Hello Jim,
I've been reading your posts over the years and you are a true scholar when it comes to wood restoration. Out of everyone I ever read concerning wood restoration you are the most detailed and the most knowledgable. If there was ever a supreme wood restoration individual you my man are it.

You took the words right out of my mouth about Knots in the wood. They are hard as nails and that is why they don't take most sealers well because they are NOT porous as some people think. I couldn't and don't attempt to try to make this anymore clearer then you did. Thanks for responding and hopefully we will read more of your posts here at this wonderful bb.

John/Clean County PW

I don't think I could say any clearer what John just said. Any time I post a question I hope that one of the responses will come from Jim. We are definitely fortunate to have him on this board to answer our questions, the same goes for Russell. After meeting Jim, I can tell you he is as good of a man as advertised, and the products he makes represent an equal dedication to quality. For the newbies to this field I would suggest going back to the PWN and doing a search of all the posts Jim has made. This is a required reading for any newcomer wanting to learn the correct answers to all things wood care.

Everyone have a great night,

Jon Fife

If it's not the knots sucking up the sealer and cleaner then where is the sealer going? I don't think I was imagining this the last 6 years.
About two months ago I was with a customer that was complaining about the white on the knots after I cleaned the deck and I actually sat there and sprayed sealer at a knot for 10 seconds and the sealer dissappeared,am I missing something here.Maybe I need glasses.Also 90% of the dry rot I come across is on and around the knots,when I stick an awl into them they fall apart.Am I imagining that also.
Also what Russel said about the knots soaking up the cleaner is he imagining that?how can knots soak up cleaner if they weren't porous in some way?
I too have noticed this.
Maybe porous was the wrong word to use,but I'd like to here an explanation why a knot can soak up so much sealer and cleaner.Keep in mind I did say older decks and there are a lot of them around me.
Well I'm off to clean my imaginary 700th and something deck!

Gentlemen,

I am sure you have heard someone say, "prices keep going up and the quality keeps going down". Well, this is really true in the timber industry.

When I spoke about knots and dry rot and such, I was refering to them in laymen terms. To a laymen, a knot is a knot is a knot and dry rot is dry rot. This is not always the case.

A knot is normally caused by the grouth of a branch/limb or seperation of the tree trunk. Through these limbs, branches and trunk, flow the life blood of the tree, sap/resions. Sometimes, more often now than before, during the grouth of the tree, vines will grow around the trunk and high into the branches. Some people think that this has a really nice look to it. Keep in mind that I am refering to trees that are used most in the building trade such as cedar, redwood, pine, fir and dougfir. What happens when these vines start growing around the tree is that they start to choke off the life blood flowing through the trunk, branches and limbs. The internal cells of the tree will not get the sap and resions that it needs to live on therefore creating what a lot of people refer to as dry rot in the heart of the tree. I have seen pines, cedars and redwoods over 200 feet tall with the inside or heart completely gone because of this. In high winds, these trees can snap like tooth picks.

When these trees are cut and milled, the knots have already started to decay because they could not get the natural resions they needed to survive on. These knots will be soft and porous. If you go to the lumber yard and look around, you'll see what I'm talking about. If your a good contractor, you'll discard any boards with this type of knot.

Now, the term "dry rot". Dry rot to a laymen means rotted wood caused by the elements. Here again, this is not really a true and complete statement. A lot of "rot" can occure while the tree is still growing. This is refered to as root desease. Root desease can cause grey rot, red rot, pink rot, blue rot and a few other rots. These different rots get their name from the minerals in the ground that the tree is growing in. Once the root has been damaged, it will absorb the minerals and create the different color rots. It's an infection much like we can get if we get cut or scratched.

The ones that we run into the most is the grey and blue rot. You will find these on a lot of log homes. If you cut a section off a log and look at the butt end, you may see a pie shape discoloration of blue or grey. If you count the life rings down to the pointed end of the pie, you'll be able to tell when the tree was effected during it's grouth. These discolored areas will be a little softer than the rest of the wood because they were not getting all the saps and resions they needed.

Well, I could go on and on about this subject but I have other work to do. Anyone can put a band aid on but this dosn't make them a Doctor. Cleaning and sealing a piece of wood does not make a Wood Restoration Expert.

Have a great day.

Jim Bilyeu,
Exterior Woodcare

In the future I would love to focus on being a wood restoration expert but for right now I work by myself and do the best I can.I don't build the decks,I just clean and seal them as you said Jim.There are certain areas where the decks were built by a builder that does the whole block and goes the cheap route which can account for the cheap grade of lumber.As a matter of fact I remember posting a question about dry rot on the knots and Jim Bilyeu gave pretty much the same answer as he did here.I respect Jims answers very much and have learned quite alot from him.I just give my advice from experiences that I have gone through and what I have seen.I work all over northern New Jersey so I see a wide range of different situations.I know that Knots are hard as rocks and for the most part are dense and don't suck up that much,I was just drawing on experiences that I have gone through with the answer I gave.By he way that trick about spot spraying the knots works on a new deck too,as this was the original question.

Also Jim if you would answer this question,If you had a ten year old deck that has been cleaned or stripped 3 or 4 times could the stripper dissolve the resins in the knot making it open for business?It seems to me that if oxalic acid can dissolve tannin stains in cedar and redwood could it also dissolve resins in the knots? Is this possible?

Hi JR,

In answer to your questions.

First off, Oxalic acid does not dissolve tannin stains. Oxalic acid will re-adjust the pH factor in the tannin stains to match the pH of the wood. This will only work if the tannin stains are not to deep. If the tannin stains are deep, you may be able to remove them from the surface but they will more than likely come back. The pH of cedar is 4.5 and the pH of pine depending on species range from 5 to 5.5.


I have seen many red wood decks where you could actually see where all the joists were at because of the tannin stains. When I build a deck out of redwood, I will lay a piece of 30 pound felt on the joists before laying my decking. This will prevent the tannin stains to appear.

There is another stain that Oxalic is good for and that is rust stains. Rust stains are caused by steel/iron being in contact with the wood. Sometimes you cannot tell the difference between the rust stain and the tannin stain. On siding it's pretty easy to tell the difference. There will be black streaks running down at every nail. Here again, a good contractor will only use stainless nails to install cedar/redwood siding. By using stainless nails, you won't get the rust stains. Never lay a piece of steel or iron on a cedar or redwood deck.

In the construction of log homes, some contractors will use black iron connectors and fasteners to hold the logs together. After a period of time the rust stains may appear on the surface of the logs showing where every fastener is at. This type of stain is almost impossable to get out.

Now, as far as cleaning or stripping a deck 3 or 4 times and removing the resions from a knot, no, this will not happen.

As far as preteating the knots first, this is actually giving the finish more time to penatrate into the knots and surrounding areas. This is OK as long as you don't get lap marks.

Have to go now but will be back later. Have a good day.

Jim Bilyeu
Exterior Woodcare

Jon, I do agree that the knots are not allowing the stain to pentrate. Boards come from different trees and will react to finishes differently. I have used Sherwin Williams Cupernoil on several decks lately in different colors and they have not had white spots. I have used these products because we do not offer our product in anything but clear. These decks turned out very nice. I like the oil base Cupernoil better than the water base. I have not thied it in clear.

Good posts Jim,

Hope you are doing well and had a good vacation.I am getting ready to head to Sweden for 2 month,9 degrees there ,so i guess i will have a long vacation,no work.Like always when i see your replies,i get excited and ready for good information.

Steven Rowlett
Hey,i was wondering if i got your post right,do you seal with clear only??We dont even mention that kind of sealer where i live,Which part of TN are you from?
See you all later
Johny

Johny, We do decks in clear with SK-60 Clear. It is product we have been selling under our name For the past year. We use the semi- transparent Cupernoil from Sherwin Williams for the colored stain decks.We have excellent results with this product. We are located just outside of Nashville.

JFife said:

hello guys,

did a redwood deck last week, the first i've done since three years ago. It looked absolutely beautiful when i left it. Guy called me back and said it had white spots on it. Went out there and he was right. It still looked good except where there were knots and grain-pattern changes. They looked white. Is there something I did wrong, or something different that must be done to redwood?? and more importantly, what can be done to fix it?? by the way, all preparation on the deck was done correctly, deck was plenty dry, didn't rain after I left. Would really appreciate some insight here, I don't see many redwood and cedar decks.

thanks guys,

Jon Fife

Click to expand...

Jon are you still around Buddy?

Steven Rowlett said:

Jon, I do agree that the knots are not allowing the stain to pentrate. Boards come from different trees and will react to finishes differently. I have used Sherwin Williams Cupernoil on several decks lately in different colors and they have not had white spots. I have used these products because we do not offer our product in anything but clear. These decks turned out very nice. I like the oil base Cupernoil better than the water base. I have not thied it in clear.

Click to expand...

Thats and old post from the chemical Doctor

Old thread for Wood