So much for 'treated' lumber

[TnAndy]

Re-built my deck 10 year ago....pressure treated lumber structure with 'plastic' decking board top. Most of it is just fine, but one place that does get a lot of water runoff, the treated lumber has completely fallen apart. 6x6 post rotted out, joists connected to it rotted out. "Wolmanized" lumber tag still on the end of one of them.

Warranty says ya got to have enough end tags to cover the number of pieces, plus the original invoice for buying it, and we'll give some more of the crap.......which means it's like most building material warranties, not worth the paper it's printed on.

 

[ovrszd]

Bummer. What's the source of water?

 

[Redlands Okie]

In the old days a piece of tar paper was laid on top of each joist before the decking went down. The idea is still a good one although there are newer products you could use also. The material on top helps shed water and keeps the joist dryer. Do not wrap or enclose the whole joist, just the top edge.

 

[lakngulf]

I have several spots where pressure treated lumber looks the same. I think there was a period (probably about ten years ago) when they moved away from arsenic and other materials and for a time did not have a decent product.

 

[bunyip]

We have had the same problem on eaves on the corners where the valley iron comes down, we used a galvanised pressed plate on the ends to prevent water ingress, seems to have worked.
We have no decking (not timber anyway) so haven't had the issue with larger treated timber beams, funnily enough though we have treated pine sleepers as garden beds, have been in for about 15 years with no sigh of rot, I think the new ones like these are pressure treated with copper sulphate.
The only problem I have had is treated timber not being straight for structural work, more twisted than a Queensland politician.

 

[ovrszd]

We have had the same problem on eaves on the corners where the valley iron comes down, we used a galvanised pressed plate on the ends to prevent water ingress, seems to have worked.
We have no decking (not timber anyway) so haven't had the issue with larger treated timber beams, funnily enough though we have treated pine sleepers as garden beds, have been in for about 15 years with no sigh of rot, I think the new ones like these are pressure treated with copper sulphate.
The only problem I have had is treated timber not being straight for structural work, more twisted than a Queensland politician.

Good one!!!!!

 

[newbury]

I've a deck I built back about '85, all the surface is PT 2x6. It weathered over the years and I replaced most of the 2x6's about 10 years ago but decided to redo the stairs and when they started to fail.
Now, posting this means the stairs will probably read the post and turn to dust immediately
But they are still holding out.

 

[EddieWalker]

I've seen something similar on decks that are closed of underneath and there is no airflow. Once it gets wet, it never dries out. How much airflow do you have around that post? What is the drainage like?

On your warrantee, I've seen the same problems with flooring warranties. You contact the manufacturer and after jumping through all the hoops, if they decide to honor their warrantee, they will ship you a replacement. If it's tile, you get another piece of tile in the mail. If it's wood flooring, you get another board in the mail. That's it. You have to figure out how to replace it, spend the money to do all the work. They only give you the new piece of whatever it is that you bought from them.

A flooring guy told me that the carpet he sells has different levels of warrantee, and you pay more for the better warrantee. It's the exact same carpet, but you pay the contractor rate with no warrantee, then the home owner rate that is more, but the warrantee is meaningless, and then their is the ridiculous priced, five star warrantee that will actually replace the carpet if you can prove it was defective when installed, which is also totally meaningless.

 

[oosik]

I have two small decks which along with stairs provide entrance to the house. Both were built, along with the house, in 1982. Both are built with standard construction grade lumber and aside from normal wear & weathering are holding up just fine.

I attribute this to our semi-arid location and the fact that all the wood in both structures completely drains after any wet weather. Treated lumber or not - if exposed to damp conditions continuously - wood will rot. The best example of that are a couple of the treated 4x4 posts in my carport. The second time they rotted off at ground level - I replaced them with telephone poles. The the tele poles have lasted 20+ years now. Look somewhat weird in the carport but what the heck - they are doing a great job.

 

[teejk]

I've heard that you should only buy pt lumber rated for ground contact. That appears to be relatively new advice so probably not well known when you built.

 

[Sawyer Rob]

I've heard that you should only buy pt lumber rated for ground contact. That appears to be relatively new advice so probably not well known when you built.

There's the right answer right there...

SR

 

[MacLawn]

Yep, tag says "above ground." It should be below grade treated for 6x6 posts, even used above ground.

 

[mcfarmall]

The only good treated lumber nowdays is the stuff that's treated with creosote and it's only available to municipalities for use on bridges, trestles, etc..

 

[teejk]

Yep, tag says "above ground." It should be below grade treated for 6x6 posts, even used above ground.

Wasn't long ago that you bought pt lumber without any designation, just "pt". I wonder where the non ground contact stuff will have any use at all. The whole industry changed after CCA was outlawed.

 

[Fossil Farm]

Residential pressure treated lumber does not last very long. It will last longer than untreated, but does not last a lifetime. Most of it has to be painted, stained or creosoted to have much of a durable life anymore, especially when it is cut and the cut ends are not retreated before installation. I have seen several 4x4's rot from the center out since the treatment only goes in an inch or two and the cut end was not retreated. Hopefully they come up with a better treatment without having to reapply onsite.

 

[TnAndy]

I've heard that you should only buy pt lumber rated for ground contact. That appears to be relatively new advice so probably not well known when you built.

Yeah, in studying the types, apparently "above ground" should have (and who really knows) 0.1lb/cuft.....ground contact is 0.2, and below ground is 0.4.

I can tell ya the 0.1 I used (according to the tag) is a waste of money and effort to put it in. IF I can find below ground in the sizes I need, that is what is going back.

There is about a foot of clearance under the deck at that point...not a lot, but the ground slopes away from the house at a few inches clearance to a foot or so at the point these rotted. Water is just normal rain runoff....they don't sit in water.

 

[ovrszd]

The right answer is oosik's second paragraph.

I asked earlier where the water is coming from but didn't hear an answer.

Edit: Whoops, hadn't read the last response.

So no water other than normal rainfall is landing on this wood?

Why did it only rot in that area? Why didn't the entire wood portion of the deck rot?

 

[Sawyer Rob]

Yeah, in studying the types, apparently "above ground" should have (and who really knows) 0.1lb/cuft.....ground contact is 0.2, and below ground is 0.4.

I can tell ya the 0.1 I used (according to the tag) is a waste of money and effort to put it in. IF I can find below ground in the sizes I need, that is what is going back.

There is about a foot of clearance under the deck at that point...not a lot, but the ground slopes away from the house at a few inches clearance to a foot or so at the point these rotted. Water is just normal rain runoff....they don't sit in water.

NOT around here!

.40 is NOT ground rated, .60 is the in ground rating and what I buy when I buy poles...

IF it touches the ground, buy .60 or it will not last real long...at least around here it won't.

SR

 

[cqaigy2]

Here in the wet PNW, i try to use concrete in and on the ground with stand off where wood will attach. The idea being reducing contact to ground and trying to keep the wood as dry as possible.

 

[300UGUY]

NOT around here!

.40 is NOT ground rated, .60 is the in ground rating and what I buy when I buy poles...

IF it touches the ground, buy .60 or it will not last real long...at least around here it won't.

SR

I used .6 treated posts for a barn, fences and a deck, 30 years ago, and nothing has rotted off yet. But you need to be careful, the stuff is pretty nasty. I've got splinters in my hands, and my whole hand swelled up, like a catchers mitt. Docs said it was a toxic reaction. I wear gloves and a mask cutting it.