Dumb question on pressure treated lumber
Just got a delivery of some pressure treated lumber for my deck (2×14’s, 6×6’s, 2×10’s, etc). So I’m standing there staring at the pile, or at the ends of the lumber to be exact, and it looks to me like the treating only goes about 1/8″ to 1/4″ into the lumber, with the inner part being untreated doug fir. I guess my dumb question of the day is what do I do with it after I start making cuts in it? Do I have to apply something to the end cuts to maintain the rot resistance? What do I do to the 2×14’s which will be cut into sawtooth shape for the stair stringers? Do I need to apply something to the entire sawtooth surface? Or am I totally off-base here, and the treating actually goes all the way through the lumber, despite the appearance?
Thanks in advance.
Leon
Replies
You're right, the treatment only penetrates so far. If you're really worried about it, there are brush-on products that would be better than nothing. Look at your local hardware store.
Oh really?? I was always under the assumption that the pressure and heat of that process forced the chemicals completely through the wood. Do you have a reference to show it doesn't or isn't needed? I'd really like to know. Thanks
It only goes in about 1/8" on Doug fir. In other parts of the country, they use Southern Yellow Pine, and on SYP it soaks all the way through.
-- J.S.
I use Jasco's Termin-8, it's a copper napthenate solution. It's more like a stain than a paint. For end grain, I just stand the piece up in a pan of the stuff and let it soak in for a while. It has a nasty hydrocarbon smell, but seems to work very well. About ten years ago I made a temporary wood walkway -- in direct contact with the ground -- using non-pt doug fir painted with Termin-8, and to this day the bugs haven't taken a bite. The neighbors' untreated fence of similar age has already collapsed from termite damage.
-- J.S.
Thanks for the tip, John. Just went out at lunch and got some Termin8 at Home Depot (along with some neoprene gloves - looks like nasty stuff), so I'm in business :).
Leon
I used some orange grout gloves, not sure if they were neoprene, when I was termin-8-ing all my stucco mouldings. They didn't dissolve or get sticky, but they did get a lot easier to tear. Let us know how the neoprene holds up.
-- J.S.
I've never heard of doug fir being used as treated lumber. Is there a label stapled to your lumber that indicates how much pressure was used to treat your lumber? If it's anything less that .40, the lumber that you have is little more that dipped. Around here, all treated lumber is either Southern Yellow Pine or Ponderosa Pine. It has been my understanding that that these two species are most condusive to treating. My experience is that rarely do I see any cut areas in SYP that aren't treated, and in the P-Pine only areas with a high pitch content are not penetrated by the treatment
My experience is it's a regional thing. All the guys out west have never heard of SYP PT, and the guys out east of Hem Fir PT (I believe that's the most common species to be treated out west). I grew up in Chicago, and everything is SYP. I guess somewhere West of the Mississippi they change over.
John Sprung:
I believe the success of SYP treatment depends on several factors, probably the biggest being the treatment company. Some 2x stock is all the way through, while other samples I have seen have about 1/3 treated, the rest looks virgin. 4x4's that I have seen are rarely completely saturated. I think your chemical is a good measure.
Jon Blakemore
Leon-
You're probably well aware, but if the stuff is preserved with the traditional favorite CCA - i.e. chromated copper arsenate (which is supposedly being voluntarily discontinued) then be sure to use a respirator when cutting, dispose of the sawdust properly - and don't burn the scraps or sawdust.
Edited 3/25/2003 8:47:53 PM ET by CaseyR
Beg your pardon, but the 0.40 number is not a measure of the amount of pressure used in the treating process. It's a measure of the pounds or gallons of chemical in the wood. You're right that anything below 0.40 is probably a waste of money.
Do it right, or do it twice.
Thanks for the tips, I'll be sure to soak all the cut lumber ends :).
I looked at my pile yesterday, and indeed most of it is treated to .40 ACQ (not CCA, interestingly). But about 6 2x4's are only treated to .17. I never even heard of such a low number, I thought .25 was the lower limit. Of course the lumber yard is taking the attitude that it's my fault (which I agree is true, since I didn't specify the treatment level). Still, despite being the "dumb homeowner", I think that calling that stuff "pressure treated" is a bit of a leap of faith :). Oh well, live and learn; just need to decide if I should use the stuff as is (it's on a second story deck) or go pick up some .40 lumber at Home Depot.
Leon
Edited 3/26/2003 12:50:47 PM ET by leon
Since you have the lumber and the can of Jasco Termin-8, I'd suggest using what you have, and paint Termin-8 onto it prior to assembly. Stand each piece up in a bucket or pan of the stuff, let the end grain soak while you paint the bottom half, then turn it over and do the other half.
As a DIY, you can do it that way without any more cash out of pocket. For a pro, that wouldn't be cost effective because it's time consuming. That "temporary" walkway at my parents' house is still going strong after 10 years in direct contact with the ground.
-- J.S.
I think the 0.40 is rated at grouind contact, the 0.60 is rated at buried, and there might be one rated for underwater. So use the lightly treated one for the handrails or something isolated from the ground.
Do it right, or do it twice.
I saw pictures of a timber foot bridge that used treated douglas fir at a materials inspection seminar. The end posts looked perfect. The reality was that the 1/2" treated exterior of the posts was all that remained. The bugs must have been eating from the first day after completion....that's not a mistake, it's rustic
Thanks for the clarification, you're right. It does of course take more pressure to impart more chemical. I think you guys who use treated lumber in marine applications have a .60 requirement. Is this correct?
Some of you talked about treating cut ends on the job. Isn't this stuff, if it's CCA, considered a hazardous material? I know that when it was introduced the mfg's said CCA was safe in the lumber because it was bonded to the wood molecules (or some such thing) and and there were no health concerns. Now, of course we are hearing a different message.
Edited 3/28/2003 7:19:23 PM ET by Steve G
CCA is a compound that contains copper and arsenic, and something else that begins with C, chromium IIRC. The paint-on or soak-in stuff you can buy is copper napthenate.
I'd guess that CCA is probably more cost effective for factory application, and the other stuff is more expensive but safer to handle.
-- J.S.
How much preservative should be in the wood?
Numbers such as 0.25, 0.40, and 0.60 pounds per cubic foot (pcf) represent the amount of preservative retained in the wood. For example, 0.25 indicates that 1/4 pound of preservative is in every cubic foot of wood fiber in the assay zone.
For water-borne preservatives: a retention level of 0.25 pcf is considered adequate protection for lumber that is not in contact with the ground or in high moisture conditions.
Most lumber treated to 0.40 pcf retention is suitable for ground contact, high moisture conditions and freshwater contact.
Lumber treated to 0.60 pcf retention is used for wood foundations, structural timbers, guard rails, etc.
from:
http://www.preservedwood.com/preswood/preswood.html
Just an observation but one high end deck builder in this area, Florida, keeps a spray bottle of treatment hung on the saw horse he keeps his chop saw on. When he cross cuts he sprays the end. He claims that the chemical treatment is less dense in the middle of the two-by and spraying on a little extra on the exposed end grain makes the deck last longer in this climate.
He also kept a set of containers made out of the bottom half of bleach bottles at hand with an inch or two of the liquid in them. All the 4by4 and 4by6 posts are placed in it to soak up as much preservative as possible. If they weren't cut they get a quick dip or two. If they are cut they stay in longer to soak. He tops up the containers regularly.
Florida is home to wood borers, carpenter bees and ants, humidity, heavy rains, several flavors of termites, woodpeckers, hot and cold running funguses, molds, algae and strong sunshine. All of which eat decks or any other exposed wood. Decks don't last long here and any extra protection seems like a good idea.
This carpenter had a grand reputation for fine decks and is, according to what I hear as he won't brag on himself, booked for at least a year in advance. I can confirm he asks 20% up front, non-refundable if you cancel, as a deposit to schedule a job. He gets top dollar and his customers still love him. Lucky SOB.
When you look at the cheet sheets that come [I know - who reads them anyway, right?] with the CCA PT, it tells you that if you are cutting off more than a certain amt from the end grain, then you are supposed to re-treat it or risk the warranty. That is one reason that the PT comes with the lable stapled on the end of the piece. An adjustor someday can see if it has been cut off.
Mine here is SYP and the only time I notice that there is treatment lacking is when I cut into a 6x6 or 8x8. I think the treatment goes two inches deep pretty good.
I think that it's mostly on the west coast that they do it with DF..
Excellence is its own reward!
The cellular structure of Doug fir is very resistant to pressure treatment, especially the heartwood. It is treated at times, usually for places where strength is desired, such as bridge timbers, or some decking products. When used for heavy service such as RR ties or power poles, the treatment is very heavy and very nasty.
Here in the West, most of the ground contact (.40 or above) treated wood is either one of the pine species, Western Hemlock, or Spruce (Sitka or Engelman). There are two treatment plants in my area which treat the majority of the structural wood going to Hawaii and the south Pacific, not to mention what stays here for regional use. Most of what they treat is Western Hemlock. The Hemlock tends to be less prone to warping, twisting and splitting than the other species. However, if the lumber is freshly processed wood and saturated with water, the treatment penetration is sometimes less than optimum, thus limiting its resistance to assault by fungi and bugs.
Regardless of how well wood is treated, it's always a good idea to coat the cut ends with one of the products mentioned in this thread. As a habit, I always try to put the uncut ends, when possible, to the point of greatest exposure. For example, on a 4 X 4 support post for a deck, put the uncut end to the ground.
Pressure treatments have so many variables it's hard to give a constant. One thing is for sure, though: theres a product on the market with the enviably simple name END CUT SOLUTION. It's fantastic, we use it a lot out here in Seattle where there's a lot of wet ground contact (can you say understatement?) One thing, though, and this applies to all CCA type solutions: Gloves are good, but EYE PROTECTION IS AN ABSOLUTE NECCESSITY!!! Check the labels. You'll find fun phrases like "irreversible,irreperable eye damage. One bad splash and it's a bad day.
For what it's worth, I just built a timber bridge and used .60 ACQ p.t. 6 x 14 Southern Yellow Pine beams and 4 x 12 sills (used untreated for the deck and rails just to be safe--we have a toddler).
Did a lot of research on p.t. and got to know the folks at the p.t. facility in my state (Maine).
I actually was so anal as to go the the treatment yard and pre-fabricate everything before treatment. Timber Bridge engineers all say that field-cuts and bores are a no-no. I did end up having to cut some blocking, and used Cuprinol's Green No. 20 preservative on the cut ends, which is basically copper napthenate. While not CCA, CN is extremely toxic stuff, so be very careful in handling and disposing of it. (I was working over a brook and didn't even dare bring the open can anywhere near the water).
As far as penetration, according to one timber bridge engineer who's written "the bible" on timber bridges, it's important that the wood be properly dried before treatment for good penetration of water-borne preservative. Obviously green or wet wood won't treat well. In labs, properly treated 6 and even 8-inch thick Southern Yellow Pine gets fully penetrated with ACQ.
One of my 4x12s appeared to have poor penetration (I used it for blocking) but when I had to bore a hole in one of the 6 x 14s I noticed that the chips were well-greened all the way through.
Incidentally, I went out of my way to spec ACQ (Ammonia Copper Quatenary) rather than CCA in order to avoid the arsenic. As you probably know, the EPA is leaning on the p.t. industry to go to ACQ for residential uses for that reason. Of course ACQ is pretty nasty as well and we'll see what the regulators are saying about it in 15 years! As I see it, the main risk is to the builders cutting, drilling, and handling it. I wore gloves and a mask and the carpenter I hired to help me just laughed--it's amazing how casual people are about the stuff.
And finally--the most important thing you can do to prolong the life of this wood is to design it to shed water and to allow air to circulate and dry out damp areas.
Good luck!
Edited 3/28/2003 10:53:46 PM ET by MONSIEUR_ED
Just out of curiousity, what did you use for the deck and rails?Jon Blakemore
Local mill here sawed me up some Hemlock--3x8 rough for the deck, 6x6 railing posts and 4x8 rails. Pretty rugged stuff. There's also a 2x8 "wearing surface" that runs longitudinally.
Bridge engineers are big on p.t. decks, but I'm not too keen on having kids playing around on poisoned wood (I'm amazed that people have p.t. play sets). I know, I know, they say that the toxic compounds are bonded to the wood and there's no risk, but all the same I'd rather not have kids touching the stuff.
i don't think this is a dumb question at all and while i'm just an amateur i had to have a guy at the lumber yard remind me that the cut ends of treated wood had to be sealed. i had just taken the attitude that hopefully everything would be ok if i just left the pieces alone after cutting them in spite of the fact that it sure didn't look as if the chemicals had penetrated very deeply. i just wish it wouldn't be necessary to use such poisonous materials but we don't want to have to rebuild our decks every 5 years either. i'm sure people who deal with this stuff on a regular basis take a pretty casual attitude, don't use gloves or care what happens to the scraps. the local recycling agency told me no one else had ever called asking about what to do with scraps or sawdust. i imagine a lot of this gets dumped into our local green bins and supposedly turned into "organic compost".
Sukebe, The new treated lumber doesn't contain arsenic. They are now composed of various copper compounds which aren't as dangerous because of our body's inability to readily absorb them. Arsenic, besides being a poison with immediate toxicity, is also a known carcinogen.
Where I am all treated is SYP and mostly treated with some copper compounds. Mostly the yard I frequent stocks only lumber treated for ground contact. I paint the cut ends with copper napthenate which is a not too scary a chemical as preservatives go.
Yes, out here in the west we must reseal all cuts. You can usually tell how deep the chemical has penetrated buy looking at the cut end. All ground contact lumber here in CA should be resealed with .9 grade sealer.
This is what happens when you don't reseal.
We build a lot of retaining walls with pt lumber. I've seen more rot from unsealed pt lumber that starts to rot within 2 to 3 years after install.
Yes, you must reseal all cuts and or drill holes in PT lumber. The stair stringers have to be resealed too. If you don't reseal your cuts it will not last the 30 YEAR lifespan that the mfg says it should last.
Out here in the west we have different grades of pt lumber. Anything that touches soil has to be .9 grade. I'm not sure the lumber yards carry the lighter treatments anymore. But I always make sure it's .9!!!
Copper green, copper brown and clear are available to reseal your cuts depending which color you are using. Either spray cans qrts or gallons.
For the drill holes, I use the spray can liberally until it drips out the bottom.
Trust me. I've installed this lumber for many years. I have jobs 10 and 15 years old and the pt lumber looks as good as when I installed it.
It's unfortunate for the client to have to replace a job because it wasn't done right the first time!! RESEAL YOUR CUTS!!!