During the change of ingredients required for pressure treating wood(removing the arsenic part) the replacement for arsenic was more copper compounds.

The old---CCA-Chromated Copper Arsenate

The new---ACQ-Alkaline copper quaternary

There was such a demand for the new product(since it was widely reported CCA was illegal and unavailable) that treatment facilities rushed production of the ACQ which cause much of the supply to be under treated.

That caused a huge amount of product that has done exactly what you experienced---rot sooner than usual. But, that was over ten years ago---a long time in the construction industry and in the retail clerk longevity situation. I'd venture saying I'd wager that only about 2% of all the BORG floor staff on the job now were on the job 10 years ago.

Another gotcha is how you built the deck. By covering the deck portion, you caused a condition where moisture could not easily dry out. The hastened the rot of the insufficiently treated wood.

A third gotcha is modern trees being grown for construction lumber. The trees are grown much faster, resulting in wider growth rings and much less dense wood grain. That increases the type of wood fiber that rots the most easily, treated or not.

Lastly, there were several caveats about fasteners to be used with ACQ---since the extra copper compounds cause steel and iron to be attacked and chemically altered.

Single galvanizing was at first thought to be sufficient, but later found to be not enough. Double galvanized was then recommended, but double galvanizing screws is darn near impossible and still have a useable product.

The newer metal formulations of the now prevalent deck screws is successful.

Also, there are more than one type of pressure treatments. The lumber you bought was not intended to be used where trapped moisture was a daily situation. The lack of sufficient treatment(basically leaving the center of the boards untreated) was the culprit.

If you can supply the necessary proof, Lowe's should honor the warranty and replace the lumber. I doubt they will supply labor or other expenses.

Best fix in my experience would be to remove the tile/etc. on the deck, replace/rebuild with properly treated earth contact rated PT wood---and use brush on treatment for cuts made on the job.

Then use composite flooring and a moveable grill protector for the grill(metal pan/etc.)

Well the weird thing about all this is I think i remember labels on the lumber with a warning for arsenic. Which would have been old style and so, they should have lasted. 2nd I know that the way I assembled spindles between the two 1x4's and next laminated 2 x 6's was a moisture trap, so I didn't caulk anything as was recommended to allow things to dry out. Next I soaked all the polls in a wood preserve mixture of Jasco it is wood preserve and termite killer and preventer. Also painted the boards down with the stuff. I tend to do over kill in my projects and that is why I am irked I am looking at this situation. I will go through my receipts and I guess I have a trip to Lowe's. I have already started with my wood hardener and wood puddy filling and fixing.

The way the wood disappearedared from the inside out, the outside rim of the post is fine, and the screws that I took out some not all were like melted that went up into the wood. Just completelyetly eaten away.

So are you saying there is no fastner for this stuff? That double dip galvanized is hard to work with or? Didn't understand that, please explain

Thanks for trying to help me.

Receipts will probably not be good, when I was in the lumber business you needed the colored tag off of the end of each piece of treated lumber. Without a tag for each and every board you will get nothing. With a tag they should replace that board with the caveat being one board per tag.

The deck screws on the shelves now are fine for ACQ.

I don't like saying bad things about national firms because the supplies they get are often local places so a product from Lowe's in New York may be fine, while the same product in Wyoming is junk. But, I found the worst place to buy framing or deck lumber in Kansas City was---hands down---at any of the several Lowe's. And that was over a 10 year period.

I also have seldom used wet PT wood ever, because it often warps when drying---another fault of wood from fast grown trees.

When I built decks, on a couple of occasions, I went to a different store to avoid dripping wet PT wood.

Without being able to see the problem(and pictures may not help), I'd say you got bad wood.

I see no reason to treat pressure treated wood., but that must be a personal thing. Cut ends, sure. The whole point of buying pressure treated is to get the treatment already done.

Thank you both for all the inside info, ahhh yes the tags, the exit door of responsibility. It's ok, I worked some more yesterday, used wood hardner then wood fill and it seems about 4-5 spindles were most effected. I painted the new boards down with preserve, over kill I'm sure. Will give it today to fully cure and hopefull put it all go back together tomorrow. I rechecked the rest of the deck and everything feels very solid. I think your right something freaky happened here. I am thrilled the rest of the deck looks good. I will however save all those tiny tags for future products.

I am surprised you are able to tile a deck. Sealing the underside also does not allow moisture to escape. Grout is not waterproof. Have never heard of this being done. I would check with a seasoned tiling professional before continuing down this path to ensure you are building a viable outdoor tile system.

This post was edited by snookums2 on Sat, Feb 23, 13 at 23:29

Thanks snook, didn't seal the underside of the deck,that was left open. You can tile decks, quite common in our area, florida! We used marine ply, its a PT plywood, then Durock then a waterproofing product, if I had known about dietra, I would have used that instead, didnt learn about that till I redid my MB. And then tiled on top of that. I rechecked the whole deck and all feels very solid. I am not sure what fell apart in this one section of railing. It is under the drip line of the roof, and we do live on a lake so in the mornings everything is wet. But the other side of the deck is solid. It is on the edge of the house and probably benefits from the breeze way and gets the sun directly on it everyday which now that I think of it the other side doesn't quite get, the deck is on the north side so there is always a shade strip from the house shadow. Anyway I think we're good for now. Thanks!