Wood preservative

Stan in Oly, WA

Well-known Member
What's the best available preservative for the cut ends of pressure treated lumber? I picked up a can of what the guy in the lumber department at Lowes recommended, but I got the feeling that it's just what they happened to have. When I got home and read the label, I wasn't impressed. My guess is that it would probably be better than nothing---but that's all. As long as I'm trying to do this right, I don't want to waste time doing something that's really no better than just going through the motions.

Stan
 
the present day cuprinol is about as best you can get--unless you can get your hands on some of the old green cuprinol or creosote
 
Stan, what's your purpose in applying preservative? If you're worried about rot, properly treated wood should not need any additional preservative after cutting. However, if you're worried about checking (splits in the end of a board caused by the wood drying out), anything that seals the end grain will help.
 
Mark, It's my understanding that properly treated wood does need preservative after cutting because the depth of penetration of the preservative is minimal, particularly when using appearance grade pressure treated lumber which lacks the incisions that enhance penetration. Personally, I think it's excessive, but it's a relatively easy step which may protect the wood from future decay, and almost certainly will protect me from future criticism should the subject ever become the topic of a certain kind of household discussion.

Stan
 
Hah! Been there.

Stan, I've seen the equipment used to pressure treat lumber and it's pretty impressive. I'm told they load the lumber into a large pressure vessel, then evacuate it. Once they've pulled a good vacuum, they then flood the vessel with the solution and pressurize it. Since the air has been sucked out of the wood, the solution is sucked deep into into it. So "properly" treated wood should have preservative all the way through it.

That said, a few years ago I bought a some 4x4s at a local store whose name rhymes with "loan repo". When I trimmed them to length, it was apparent that the PT solution had not fully penetrated the wood. The posts have held up OK, but rot is not a real big problem here.

You used to be able to by copper naphthenate at the hardware store, but that went away when they outlawed CCA. Anything to seal the end grain will reduce rot and checking. Boards tend to rot from the end grain because rot fungus is drawn into wood anytime it absorbs water, and water migrates fastest through the end grain.
 
I used to haul directly from 2 plants, 4 years worth of keeping the yard stocked with CCA treated lumber, the vessel is impressive, as is the process.


The EPA has quite a bit of information on CCA and I don't know, but I think a lot of this came from Picnic tables and them using it in school yard playgrounds, + Arsenic, but the material did perform well, now they treat it like lead paint.

Osmose, I believe still makes CCA treated wood and the EPA does have a list of approved uses, I do believe you can order it, some of the uses are utility poles, agricultural fences, not sure if they list pole barns or ag buildings, I did post links quite some time ago, its on the web. Osmose link below does have a link to the EPA site. The next link is interesting reading, CCA works fine and is safe when used properly, its just people that are ignorant.
OSMOSE

Wolmanized CCA Poles interesting reading
 
Treated lumber that is used for foundations is different than what you use on your deck. I think there is 3 diff. levels of treatment.
 
Stan, some interesting reading below, it make sense given the material you are using, though I was of the same opinion of Mark, you can't get CCA as easily, I am not sure how the current ground contact material performs, CCA worked just fine, I used to handle it, crystallized CCA on the outside, wore gloves, and you don't want a splinter of this in you, or burn, eat or what have you, and I agree with it not being a good idea for playgrounds, but... people just being ignorant, fueled by some sort of activist movement directed towards the EPA, was likely the cause, I think you can order CCA though, see the links below, its still in use, but limited, and though not banned by the EPA, the wood preservative manufacturers seem to be in some sort of agreement about its limited use, as we do live in such a litigious and seemingly at times, ignorant society, no doubt as to why it went this way. ACQ and CA are the latest treatments available, I am not well versed in either, I do wonder if the ground contact preservative used today will perform the same if so, fine, but why is CCA still the choice for industrial use, it was everywhere for years and years. Same thing with creosote, fools ruined its availability, you can't dig a hole and fill it with creosote to soak logs with, like they did I am sure, its fine to use and use properly, I had some left over from years ago and applied it to the bottoms of 70's era 6"x6" x 18' posts, that have been in well drained ground for 7 years, to help prevent rot or decay, seems to work fine, no leaching ever, grass and weeds grow right up along them.
 
In NY state you now need a pesticide applicators license to apply many wood preservatives that are only sold industrially.
Pressure treated wood really only absorbs treatment in the sapwood, so when cut thru there is hardly any preservative in the heartwood---thus the need to treat cuts and bolt holes.e always specified 3 separate coats of preservative to cuts, and the use of a pressurized bolt hole applicator for the bolt holes.
 
I believe I read that about the applicators license. The thing is with fresh lumber from the plant, its great to use right away, but its still saturated, its hard to figure even with a pressurized applicator how it will absorb the preservative. If you dry the lumber, smaller dimension does like to warp. Large dimension, timbers and poles maybe not so much.

I can recall how heavy those units of lumber were. We had a delivery one day and the derelict, and or drunk forklift operator, popped a band on a unit of 2x12x16's on the opposite side of the trailer, with one of the forks, releasing most of the lumber onto the driver who was rolling up straps on the other side, and of course it was the top unit, he was crushed and severely injured, nice fresh CCA saturated boards.

There used to be blue and red tags, red was .60 CCA, I remember seeing that in 12"x12", I had bought a cut off from a yard I delivered trusses to.
 
most of the projects I was involved with were for shoreline structures---NYSDEC required us to have a 30 day air dry time before using. Needles to say a lot of lumber was returned as it exceeded the warp, twist and straightness specifications.
 
Hello Stan In Oly, WA,

I dip wood exposed to earth in driveway sealer.

Guido.
 

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