He dropped off a load of pressure treated lumber at my house so I can finish out my train basement. Problem is some of this pressure treated wood has flat white splotches on it. I can’t believe my lumber supplier would be stupid enough to deliver pressure treated lumber with mold over it. But I want to be sure.
Could this be mold? Could it be something else? Would it help if I supplied pics? And would bleach water wash over the lumber take care of the problem?
~Thanks
~D
If it’s truely pressure treated lumber, then it’s unlikely that the splotches are mold. Wood mold is usually black. It could be some kind of chemical though, so I would recomend contacting the supplier to investigate futher before cutting and getting it airborne.
Pressure treated wood will not mold or mildew, so the white spots are probably the chemical used to treat the wood or are sap oozing out of the wood if it was still green when treated. All of the pressure treated wood I used had a dark or gray color to it, with an aged-copper tinge. The appearance is going to depend on the type of wood and the chemical used in the treatment process.
Be sure to wear gloves when you handle pressure treated wood, and an OSHA-approved respirator when you cut it.
I agree, phone and ask them why this plaque would be on the wood surfaces. Perhaps a second call to a landscaper who might use such timber outdoors to see what they know about the phenomenon.
AFAIK, molds are killed by several things, including copper and sulphites. For example, if you get molds or mildew on garden plants during extra humid or damp conditions, you can spray the leaves with a copper solution to forestall mildew. Alternately, and probably cheaper in the long run, you can get potassium meta-bisulphite from wine and beer making supplies stores, for cents. Mix the white powder at the rate of 1 heaping teaspoon per quart of water and use a sprayer to cover any surfaces you are feeling iffy about. A mold (and bacteria) will quickly succumb to a bisulphite wash, as they are meant to do inside less than clean bottles and caps/corks during bottling procedures.
Contrary to popular beleif pressure treated wood can have mold/mildew ON it. It will typicallly be a blackish substance that resembles a slightly damp powder.
I’ll agree that the white splotches sound like a chemical residue/reaction, especially if the substance is a powdery consistancy.
[edit addendum without changing the above statements]
the mold on PT lumber is not from the lumber itself but from excess moisture trapped between the boards while they sit for weeks/months waiting for delivery.
Thanks for the valuable information guys. A great resource as always.
I’ll post some pictures this weekend. I’m not sure I can count on my supplier to give me an honest answer as he dropped these off 2 months ago. (I’m finally getting around to finishing the last section of the basement.)
I’ll see if I can get some of that stuff you were referring to selector. Thanks. I don’t want to toss out 24 PT 2x6x10s’!
~Don
Don, check your PM
Depending on the exact treatment method used, you might be looking at a deposit of boric acid powder. The same stuff that gets mixed with water for footbaths is also a very powerful mold and insect killer.
No matter what treatment was used, handle with gloves and wear a filter mask and safety goggles when cutting or drilling it.
Chuck (modeling Central Japan in September, 1964)
Most of the treated lumber out there in the market had a chemical change done in in the treating done about 2 years ago. They changed it and never said anything about it for about a year, It contain a copper sulfate type base and some other types of newer chemicals , CrCQ rated I beleive. Galvinized and straight steel type fasteners will be eaten in about a year, this is from the new chemicals used in treatment, Triple coated, and stainless should be used.
The white powder you are seeing has a very lite blue in it does it not? This is the over saturated wood bleeding off the chemicals. Its nothing to worry about, but just dust it off and don’t get it in your eyes. As everyone else stated, black is mold, and has a bad oder to it.
What are you doing with all that PT 2x6 anyway? I first assumed it was the 2x4s for shoes for the studded walls, but 2x6?
Maybe i am wrong…but i was always under the impression that pressure treated lumber is not recommended for indoor use. If you have to wear gloves & respirator when cutting it, don’t you think the chemicals would be harmful being permanately in the basement?
The different designations escape me at the moment but there are at least 2 classes (Groups) of PT lumber. One is OUTDOOR ONLY due to the chemical hazards involved with indoor use and the other is INDOOR ONLY due to the lack of outdoor exposed weather resistance. Both are recommended to be cut/drilled/machined with the use of personal protective equipment (PPE), depending on the work being performed.
Hi,
I’ve worked with pressure treated lumber a lot, and would bet the RR that the substance you see is the chemical treatment used in the preservation that has oozed out.
FWIW, I urge you not to use pressure treated lumber indoors. If humidity is your reason, then I would invest in a dehumidifier instead. Pressure treated lumber is definitely toxic, and the handling and/or breathing of its dust (when cutting or sanding) is not a good thing. Yes, if you use gloves/respirator you will be fine, but also please do you cutting outside.
Oh, one more thing… treated lumber is definitely more difficult to work with, which is one more reason to use untreated lumber for your benchwork.
As they say… “trust me”!
Mobilman44
This whole discussion is just reinforcement for my satisfaction with my non-toxic, non-allergenic choice for benchwork construction material.
It isn’t too late to switch to steel - and steel stud material is definitely less expensive than any kind of treated timber product.
If you’re building a large layout, framing it with steel will save more than enough to pay for a good dehumidifier, which you will want to protect your electronics anyway.
Just my [2c]. Other opinions are sure to differ.
Chuck (modeling Central Japan in September, 1964)
My sentiments exactly. This is why I was asking what these were to be used for. The use of a PT 2x4 for the shoe, base plate or whatever you call it in your area is understandable and some local codes required it for contact with concrete.
To use pressure treated, especially yellow pine for benchwork is a real mistake. Besides having this material indoors and exposed, it is a poor choice for benchwork. It doesn’t season well and has a mind of it’s own. If PT yellow pine wants to split, twist, cup or curl nothing will stop it. This is a main reason you will never see it used as framing lumber within a structure. Cracked DW or plaster anyone…
If you’re really intent on using this stock for benchwork, I would suggest washing/scrubbing the pieces to clean off the excess chemicals (outside), allow to dry then work with it. That discoloration and residue is not any problem. Drill and screw, any nailing is guaranteed to split pressure treated lumber, not right away but as it dries.
Yes, mold will grow on pressure treated wood. A simple and quick wipe-down with bleach will get rid of it almost instantly. We sometimes have to do this at the woodshop I work at part-time.
If you check the EPA web site, I believe you will find that the arsenic-bearing treatment compounds are no longer allowed (although pre-existing stocks can be consumed). Even wood with the old arsenic-bearing treatments can be used indoors, it appears, subject to all the same caveats re: cutting, handling, etc., that apply to exterior use. The EPA site discusses the newer alternative treatments.
As for yellow pine, (usually Southern Yellow Pine), especially if it has been kiln-dried and treated, is not especially prone to twisting, cupping, warping and the like. Nor is the treated wood particularly prone to splitting when drilled, screw
[quote user=“dante”]
If you check the EPA web site, I believe you will find that the arsenic-bearing treatment compounds are no longer allowed (although pre-existing stocks can be consumed). Even wood with the old arsenic-bearing treatments can be used indoors, it appears, subject to all the same caveats re: cutting, handling, etc., that apply to exterior use. The EPA site discusses the newer alternative treatments.
As for yellow pine, (usually Southern Yellow Pine), especially if it has been kiln-dried and treated, is not especially prone to twisting, cupping, warping and the like. Nor is the treated wood particularly prone to splitting