[OP]
Contributor
I built some fence using treated 4x4 posts. The 15 year old posts are fine. some of the ten year old posts are rotted off about 6-8" down all the way. I doubt I still have receipts but I might. Home depot has never had labels saying if it is ground contact or not. Logically since they do not say it should be implied fence posts are ground contact treated.
Any hope of getting replacements for free. I know they will not pay for my labor
Bill D.
Contributor
there were pressure treated posts here from 84. I pulled them a few years ago with a post puller. Turned out no concrete in the ground so pulled out easily. This is older green pressure treated. The part in the ground on all of them was treat, just about good enough to put back on the shelf. Testament to the old nasty chemicals.
Contributor
Copper napthalate ( Warning spelling was a guess) , is real good for treating wood for ‘ground contact’ . Hard to find now.
Contributor
Contact the store for warranty information. I'm in the Pacific Northwest and the supplier here has a limited lifetime warranty; I checked a HD store near Modesto and some 4x4 PT apparently doesn't have any guarantee.
Contributor
CCA treated was a long lasting product. ACQ treated does not last very well. I have had to help several clients wade through the warrantee process. It is terrible. The lumber company reluctantly gave us a few new boards. There are several on going class action lawsuits. The homeowners rarely get any help. I have had to build several decks a second time for free. One project rotted so fast and so bad that I had to send samples of the wood to a lab to prove that I had indeed used treated lumber, despite having all of the receipts and delivery records. A fence post is the only place I put wood in contact with the ground. I tell folks "it should last 10 years".
Member
New treated lumber has to be safe enough for children to eat.. so it just doesn't work.
Contributor
There's treated and then there's treated. You need to read the tags. UC4B or 4C treated lumber will outlast the more typical UC4A by a lot, and the above ground UC3B treatment by even more. If it doesn't carry a AWPA tag there's no way to be sure what you are getting. The rating achieved is more important than the particular chemical used to get there.
Contributor
I keep wondering how the moisture content of the lumber before it goes into the pressure vat affects retention. Even when I go out of my way to get the highest retention rating I find boards or posts that have areas that retain very little chemical.
Friend of the Creek
Isn't there an inherent danger of kids getting splinters in their mouth?Originally Posted by Jared Sankovich
Regards,
Tom
[OP]
Contributor
I think it is true that the solid posts are treated green and the rotten ones are the new and improved brown treatment.
Bill D
Contributor
Do what I do instead. Use aluminum or galvanized steel poles for your posts. Sure, they're more expensive, but only slightly and they'll outlast you (50-70 years vs. 10-15). So once installed, you'll never replace them again. Then the next time you need to hang a new fence, it's easy. No digging. Your future self will thank you.
I've been slowly replacing all of my fence posts, one at a time as each on rots, with galvanized poles. That makes it affordable and easy to do. As of now, I only have one wooden fence post remaining. It's been an ongoing project of mine for the last 10 years. And the first ones I installed are still good as new. The wooden boards I hung on them are ageing though. They might have another 5 years left in them.
Contributor
If there is no description about the rating, you should have gone somewhere else.
Contributor
It doesn't affect the end product for a few reasons, as long as the standards are being adhered to:
1] the treating standards require use of KD-19 lumber, which means the m/c has to be 19% or less
2] Before the pressure cylinder floods and pressure is applied, the first step is to pull a hard - HARD - vacuum. Hydraulic vacuum, not pneumatic. This is done to remove as much moisture as possible, so the "thirsty" cells will soak up the chemical soup as fast as possible. No benefit to prolonging the treating cycle. FWIW - the process wraps up with another hard vac cycle. No benefit to leaving excess water in the product, and some negatives, including more weight = smaller shipping payload per $/mile
3] When the cycle ends, the cylinder opens, and the tram full of lumber exits. Multiple [I forget how many] core samples are taken at specified depths and placements in the load, and combined for testing the chem retention. These records stay on file for auditing.
Yeah - that can definitely happen. Heartwood ain't gonna play ball. No matter how hard and for how long you hammer on it, the chem is not going to make much, if any, progress into that dense cell structure.
Noticeable in posts and - especially - in the products they call landscape timbers. Those are nearly all heartwood, and the standards for that product is "Treated to Refusal". Meaning the treatment cycle only goes until no more can go in, which ain't much
"Retention rating" refers to the chemical mix ratio, and is a gauge of pounds of chemical per cubic foot of wood. This is controlled by the mixture of chem to water in the soup. Fence boards and deck balusters are the lowest. Ground contact is higher - but you still can't push it into heartwood. Then the scale keeps climbing - I think saltwater immersion is the highest.
Another comment was about HD labels not saying "ground contact". Their literature and shelf labels and advertising all say that - the teeny labels probably don't have enough room. Plus, that's t he industry standards again
When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.
Contributor
We're fortunate here that there is a big demand for treated lumber because so many use it for docks on posts and bulkheads along the shoreline. There is also a local treatment plant that caters to this market. I would almost never buy treated lumber, and never for ground contact, from a box store.
Contributor
Would you explain, please, what you mean by "hydraulic" vs "pneumatic vacuum?" A vacuum is a vacuum.
And I don't believe the vacuum used in pressure treating is particularly hard, at least from a physics point of view. Unless I'm mistaken, the standard approach goes down to about 20kPa - which means they remove about 80% of the air in the chamber/wood. I do way better than that with a vacuum bag for veneer pressing. The intent is not so much to dry the wood, as to remove that would otherwise have to be compressed by the pressure treatment, and which would provide hydraulic pressure to expel the treatment when the pressure is removed.
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