Author Topic: oiling timbers w/ "mildew" spots (Read 1717 times)

FrankLad · « **on:** July 25, 2007, 11:45:38 am »

We have sanded (and sanded and sanded) the lower portion of our timber frame, including posts, braces, and top plates to get rid of some greenish spots that showed up after the frame was subjected to several weeks being uncovered (rain and sunlight).

The only timbers not sanded are the rafters. I tried some stain on a 8x10 sample block, part sanded and part with stains left, and it actually looks fine. It's a darker stain, which I think helps mask it a bit.

I've checked with a local mold/mildew expert who says that oil stain would not feed the mildew, and I should have no problem. Then again, I've read where stain could cause the "mold" (this expert fella looked at a block of wood and said he wouldn't even call it mildew or mold) to search for oxygen/water and expand.

I am not 100% clear on any of this. I just know I'd like to stain the sanded timbers as well as the unsanded rafters. I know there'll be a slight difference in tone between the two, but as they are separate members (and not sanded + unsanded on the same timber/member) it should look fine.

...Just wondering about long-term effects as far as mildew growth (if it even is that). Maybe I should upload a pic.

Any ideas?

FrankLad · « **Reply #1 on:** July 25, 2007, 01:28:27 pm »

Ok, I took a ride out to the house during lunch and snapped a few pictures.

Staining on unsanded timbers:

Here's a beam that was sanded, but still has some deep staining:

Fla._Deadheader · « **Reply #2 on:** July 25, 2007, 04:11:43 pm »

Would it be possible to spray them with a weak solution of Clorox and water ??

I have done this many times, and it cleans up like new.

Try a spot. Mix about 1 cup of Clorox in a gallon of water, more or less.

FrankLad · « **Reply #3 on:** July 25, 2007, 05:00:41 pm »

I've tried Water + Bleach (4 to 1 and later 1 to 1) as well as Water + Bleach + JoMax. Neither worked. The outer surface of the wood maybe gets a tad lighter, but the green spots remained.

Thanks for the suggestion, though!

Dodgy Loner · « **Reply #4 on:** July 25, 2007, 08:37:01 pm »

What you've got there is blue stain fungus. It occurs in softwoods when they stay wet for too long. It does not affect the strength of the timbers, but there's no way to get rid of it. A lot of people actually like its appearance. Just think of it as added character to your wood!

aniakhenry · « **Reply #5 on:** July 25, 2007, 10:31:15 pm »

I think that Dodgy Loner is correct. It just looks like water stains. I used to be a painting contractor and a wood restorer may help?? I used to use a product called X-180 and it was amazing how it would turn aged and grayed wood to look absolutely brand new. It is reasonably priced and can be bought in 1 gallon containers. I think it can be deluted or used straight. It is environmentally ok also. Great product.... Maybe go to a paint store, a mean a real paint store not home depot or lowes.... and ask them for wood restorers and tell them your problem.

Good Luck

Don P · « **Reply #6 on:** July 25, 2007, 11:53:58 pm »

I think DL is correct also and nothing is going to touch it. If the surface is down below ~ 20-25% it will not get worse. I've never seen a finish "feed" it.

Radar67 · « **Reply #7 on:** July 26, 2007, 12:01:33 am »

If it is mold or mildew, you can spray it with distilled white vinegar to kill it. It won't take away the stain, but it won't let it continue to grow.

Stew

FrankLad · « **Reply #8 on:** July 26, 2007, 12:05:26 am »

THANKS SO MUCH!

It's really reassuring to read your comments. I feel so much better about the situation.
I'll check with the local paint supply store on that X-180 or similar cleaner. If I can't get it
locally I'l just go ahead and oil it as-is, knowing that no harm will be done.

Thanks again, very much!

beenthere · « **Reply #9 on:** July 26, 2007, 12:09:47 am »

If it's mildew, I'd go with FDH's recommendation and the chlorox solution. That will get it as good as possible without sanding and spending a lot of money. Just spray or paint it on with a brush, depending on how much splattering you can tolerate and ease of working on the wood.
It's not mildew if chlorox doesn't clean it up.

The X-180 is oxalic/hydorchloric acid, according to:

MSDS on X-180

FrankLad · « **Reply #10 on:** July 26, 2007, 03:07:23 pm »

Yeah, the stuff seems to be pretty deep in the timbers - further confirmation of it being blue stain fungus.

Here's an article I just found, and wanted to share with anyone else who may be interested:
Blue Stain Fungus Article

jpgreen · « **Reply #11 on:** August 14, 2007, 01:27:07 am »

Interesting as a friend of mine is a grader from a commercial mill now closed down, and he claims blue or staining of any kind is the begining of rot, and that it will keep going, and I couldn't disagree more.

I took the pressure washer to some molded pine and it still will not remove the stain. Surface mold yes. Plane work removes the black uglyiest part, and smooths out the staining, but it's deep and will not get rid of it. I had no luck with clorox either.

Don P · « **Reply #12 on:** August 14, 2007, 07:00:10 am »

Bluestain is not a rot but it is an indication that the conditions are right for wood destroying fungi. Bluestain feeds on the sugars within the cell cavity not on the cell wall. Rots feed on cellulose, the cell wall itself.

That said, sapstain does damage the wood. Micrographs of the hyphae show that they bore through cell walls from cell to cell. This is why the wood slowly becomes more hygroscopic as the stain advances. For that reason I'm leery of using wood with much stain in exposed locations, fearing it will hold more moisture and possibly lead to rot.

If you watch, sometimes you can see it follow rays and then spread out from there.

There is some accurate information and some good micrographs here;
http://legacy.ncsu.edu/WPS202/fungi/fungi.htm
http://legacy.ncsu.edu/WPS202/fungi/decay.slides/index.htm

TexasTimbers · « **Reply #13 on:** August 15, 2007, 10:22:30 am »

I have sprayed 4 timbers so far t hat had mildew and one t hat had blue stain, with a 50/50 solution of clorox and water. Each one lost it's mildew/stain completely except one t hat still had a few spots. I waited a couple more days and hit them with straight bleach and they were gone in another day. I don't know if they will reappear as I didn not spray t he end grain because I wanted t o see how deep t he clorox went, and y ou can tell t hat t he inner stain remains.

I might have t o treat them from time t o time I don't know, but I am holding off putting any oil or sealer on them for now. They are all in service now.

beenthere · « **Reply #14 on:** August 15, 2007, 03:46:32 pm »

kevjay
That is what I'd expect to happen. Glad it did for you.

FrankLad · « **Reply #15 on:** August 16, 2007, 01:37:43 pm »

I'd hate to think that this stuff is harmful to the wood. I've even noticed lighter instances of it on the 2x T&G flooring, 2x6 SYP studs from the lumberyard, and on some 2x4 spruce pine studs (faint/light) as well.

Spoke with a damage remediation guy and he says it's very common. He added that any house w/ wood exposed for a rain or two will start to get it.

beenthere · « **Reply #16 on:** August 16, 2007, 05:09:16 pm »

Frank
Not following your last post, and what it is you are referencing to...

i.e. "this stuff"

"lighter instances of it.."
"..it's very common.."
"...start to get it"

Mildew the "it" here? or blue stain?

Just curious.

TexasTimbers · « **Reply #17 on:** August 16, 2007, 05:58:21 pm »

Can't speak for him but I'm guessing he means the blue stain.

Don P · « **Reply #18 on:** August 16, 2007, 08:00:03 pm »

If so I probably spoke too strongly, it was not my intent to unnecessarily worry anyone.
I think I better hush and leave it to those more capable

.

Engineer · « **Reply #19 on:** August 16, 2007, 08:23:03 pm »

My timber frame house is full of the stuff. In many cases I encouraged it prior to drying the wood. I will try to take some pictures of the plank floor that has lots of blue stain and post them here. I did try getting it out with various cleaners, chemicals and sanding and nothing worked, so I allowed it to happen. If I ever find something that removes it, I might try it, since all the timbers in my house are and will continue to be raw wood.

beenthere · « **Reply #20 on:** August 16, 2007, 08:29:23 pm »

Don't do that Don. Your info was very good, and covered some of the basics. A good indication of conditions at the time the blue stain happened. Getting the wood out of those conditions will help keep it from rotting away. The blue stain in dry wood isn't a strength problem, according to what I've always heard anyway.

Some of the advertising hype that can get bantered around might lead us to think we should buy more chemicals to treat the wood for something it may not have to begin with. But if it sells treatments, that is priority to the mfg.

FrankLad · « **Reply #21 on:** August 17, 2007, 09:35:47 am »

Quote from: beenthere on August 16, 2007, 05:09:16 pm

Frank
Not following your last post, and what it is you are referencing to...

i.e. "this stuff"

"lighter instances of it.."
"..it's very common.."
"...start to get it"

Mildew the "it" here? or blue stain?

Just curious.

Oh, sorry! I was talking about the blue stain.

Engineer: I'd like to see pictures of your floor. As mentioned, our 2x T&G flooring (forming the 2nd floor and ceiling for first floor bedrooms) has some light instances of the stain on them, but it actually doesn't look bad. I think perhaps because the T&G was dry, as opposed to the wet timbers.

I read and just thought "the beginnings of rot" meant even if the timbers were housed/protected, so I did get a bit worried for a minute. Here I was, picturing our timber frame gradually getting weaker and weaker as time passed.

... but I now understand it to be that the wood will rot IF left in those original conditions that caused the blue stain in the first place (left out in the weather).

Quote from: Don P

I think I better hush and leave it to those more capable

Nossir, don't do that! I appreciate all the info you guys give, as always!

News:

Author Topic: oiling timbers w/ "mildew" spots (Read 1717 times)