I bought some pressure treated lumber yesterday…

[Packard]

I went to Home Depot yesterday and bought some P/T decking and two 4” x 4” x 8’ posts.

They were very green and very wet (and very heavy).

Later in the day, after placing the P/T lumber on my deck for use the following day, I saw that I had a nasty purple rash on my hands and forearms. 

A shower and some cortisone cream addressed the issue and the rash is gone this morning. 

I will be using gloves and eye protection (and probably a face mask) when I resume the repair work.

I never had this issue in the past.  Did they change the formulation again?

In any case, wear skin protection, eye protection and probably a face mask when using P/T (and keep some cortisone cream in the medicine cabinet.

 

[Ron B]

I do not know if formula has changed recently, but here is my experience.  My deck has some 30+ old posts and some 15-year-old posts (replaced because tree fell on deck).  I noticed on the 15-year-old posts some soft spots on top end grain.  I started poking around with a screwdriver, then got a longer rod and discovered the posts were mush 18" down through the center.  My 30-year-old posts are still good.  So if you are doing any deck work with posts, be sure you buy those "decorative" little end caps because apparently, they are more than just decorative.

 

[woodferret]

PT is pretty much 'skin deep' hence when you cut it, you should technically use a cut sealer.  Also, since we switched from CCA, the expense of treatment for ACQ/CA have caused us to split into various retention levels in addition to AWPA (US) categories.  Weathering and contact will wear different PT down faster. 

As for allergies, well.... there's ACQ/CA/MCQ/MCA.  No idea what box stores sell as PT these days vs old... (it's labelled on the wood though).  Totally agree on the PPE though regardless.

 

[Cheese]

I've installed cedar posts, treated posts and old growth redwood posts. The redwood lasted about 20+ years, the treated about 9-10 years and the cedar 6-8 years.

The only thing that seems to extend the lifetime of wooden posts is to coat them with several thick coats of automotive undercoating, paying particular attention to the bottom of the post. Let it dry thoroughly and make sure there is a continuous barrier around the entire coated surface. Be careful during installation and transit not to scuff/damage the coated surface.

Here's a cedar mail box post that I coated & installed on August 2014 for my mom. Ten years later, it's still as solid as the day I installed it.
If I bury a post 36" deep, I'll spray the post up to the 38"-40" level. If setting in concrete/Quikrete, raise the concrete fill about 1" above ground level and then taper the cement cap on all sides to shed water.

[attachimg=1]

 

[Tom the Remodeler]

For mailbox posts, I've had good luck using pea stones in the hole in lieu of concrete. Most wood rot occurs when the wood can't dry. It's not unusual for new posts to have a rather high moisture content, if you pour concrete around them and the wood shrinks now you have a void between the wood and concrete for water to sit in and rot the post. Using a drainable material such as pea stones or river rock allows for moisture to drain past the post. I make sure there is ~6" of stone underneath the post so it's not resting on soil. Bonus to this method is that when the post inevitably rots out, you can remove and reuse the gravel, whereas with concrete you have a cure concrete plus stuck in the ground with which you must now deal.

 

[Packard]

Angle cuts at the top of posts prevents most standing water. But the caps work better.

 

[Duckler]

I have been using disodium octoborate rods in wood that is outdoors. There is also a powder version that can be bought.
The chemical is fatal to the bacteria which feeds on wet/damp wood. When treated wood gets wet the chemical dissolves and leaches through the wood.
It is definitely a time-consuming process to treat your own lumber this way. But it is a bit like buying insurance, IYKWIM.

 

[live4ever]

I’ve never gotten a clear answer as to whether PT lumber should or should not be coated in some way when buried or encased in concrete.  Some say it accelerates rot, while others have good success (first time I’ve heard of the underbody coating method, thanks [member=44099]Cheese[/member]).

I do swear by tapering the top of the concrete base and even using some crack sealant at the base of the post as the wood inevitably shrinks away.

 

[Packard]

I've installed cedar posts, treated posts and old growth redwood posts. The redwood lasted about 20+ years, the treated about 9-10 years and the cedar 6-8 years.

The only thing that seems to extend the lifetime of wooden posts is to coat them with several thick coats of automotive undercoating, paying particular attention to the bottom of the post. Let it dry thoroughly and make sure there is a continuous barrier around the entire coated surface. Be careful during installation and transit not to scuff/damage the coated surface.

Here's a cedar mail box post that I coated & installed on August 2014 for my mom. Ten years later, it's still as solid as the day I installed it.
If I bury a post 36" deep, I'll spray the post up to the 38"-40" level. If setting in concrete/Quikrete, raise the concrete fill about 1" above ground level and then taper the cement cap on all sides to shed water.

[attachimg=1]

I may go and buy a couple of cedar posts.  The P/T posts are extravagantly heavy.  And the dark green and black colors are through and through.  So these posts may have been in the pressure cooker for longer than normal.

I will weigh them in the morning.

The original deck was made from Douglas Fir in 1953, and none of the wood had been replaced until I moved in back in 1999.  Some of the Douglas fir was near the end of service life back in 2000 when I started replacing parts bit by bit.

This deck is grandfathered in, but would not be allowed by current code.  To replace the posts, would require digging down about 10 feet to pour the footings.  Back in 1999, the price was $3,500 per post (five posts total) or $17,500.00 ($32,600.00 in 2024 dollars).

And that was just the posts. 

But I could replace bits and pieces as required. 

My current deck is like “Lincoln’s orginal axe used to chop down the cherry tree.  Handle was replaced 3 times and the head was replaced once.”

There is about 5’ of ledger board that is still original to the first deck.  Everything else has been replaced.

I was rather impressed by the performance of the Douglas Fir. The main problems were where there were two 2” x 8” board sistered up.  The water apparently got trapped between the boards and caused the rot.  The single boards were in good shape. 

Does anyone use Douglas Fir for decks anymore?

 

[live4ever]

I've installed cedar posts, treated posts and old growth redwood posts. The redwood lasted about 20+ years, the treated about 9-10 years and the cedar 6-8 years.

The only thing that seems to extend the lifetime of wooden posts is to coat them with several thick coats of automotive undercoating, paying particular attention to the bottom of the post. Let it dry thoroughly and make sure there is a continuous barrier around the entire coated surface. Be careful during installation and transit not to scuff/damage the coated surface.

Here's a cedar mail box post that I coated & installed on August 2014 for my mom. Ten years later, it's still as solid as the day I installed it.
If I bury a post 36" deep, I'll spray the post up to the 38"-40" level. If setting in concrete/Quikrete, raise the concrete fill about 1" above ground level and then taper the cement cap on all sides to shed water.

[attachimg=1]

Does anyone use Douglas Fir for decks anymore?

I’m sure there are occasional budget-oriented folks who still use it for joists in the right situation and paint all six sides and use joist tape or flex seal on the tops, but it seems like a pretty bad idea with today’s Doug Fir, which is nothing like the old-growth you could get back in the 90s.  Seems like best case it would last 10 years.  Kind of hard to justify the extra effort vs cost savings compared to PT.

 

[Vtshopdog]

FWW - I did a semi deep dive on treated lumber fall of 2020 at height of wood shortages.  Long and short there are multiple types and ratings for PT lumber and there was very good information on a pressure treated lumber trade association website but I don't have the link.

Also be aware that the new generation treatments are significantly more corrosive to fasteners and hanger hardware than the old green stuff.

I started a thread about rebuilding my deck during that project and some good links about corrosion are in post #15:
https://www.festoolownersgroup.com/home-improvement-other-projects/how-to-save-early-90's-redwood-decking-rotting-framing-rusting-screws-stuck/msg621346/#msg621346

 

[Cheese]

I may go and buy a couple of cedar posts.  The P/T posts are extravagantly heavy.  And the dark green and black colors are through and through.  So these posts may have been in the pressure cooker for longer than normal.

That'd be my suggestion...when treated lumber gets soaked and it isn't dry enough, it will eventually dry out but that inevitably leads to warps, twists, splits and cracks. When I use treated, I make sure it's not too wet and if it is, I'll go to another store and see what they have to offer. Using soaking wet treated lumber is just not worth the risk. I've thrown too much of the stuff away.  [sad]

I'd suggest using the cedar posts coated with automotive undercoating...I'll check back in 10 years from now just to see how well they're still doing.  [big grin]

 

[Packard]

I just weighed the 4” x 4” x 8’ p/t posts.  Each one weighs 37 pounds.  Is that in the expected weight range?  What ould cedar posts weigh?

 

[woodferret]

I just weighed the 4” x 4” x 8’ p/t posts.  Each one weighs 37 pounds.  Is that in the expected weight range?  What ould cedar posts weigh?

Linear weights for 4x4 PT would be 6.21lb/ft (wet max) down to 3.52 lb/ft (dry) on southern yellow pine.  Most of that's just plain water during the pressure treatment.  The actual ACQ/CA in that is on the range of 0.37% over untreated wood.  On your end tag (probably back of), there'll be a AWPA use category and subsequently a retention level from the mfg.  It's in lb/cu. ft if you want to count pennies.  It's more an important number to figure out what type of fastener you should use.

 

[Cheese]

I just weighed the 4” x 4” x 8’ p/t posts.  Each one weighs 37 pounds.  Is that in the expected weight range?  What ould cedar posts weigh?

Linear weights for 4x4 PT would be 6.21lb/ft (wet max) down to 3.52 lb/ft (dry) on southern yellow pine.  Most of that's just plain water during the pressure treatment.  The actual ACQ/CA in that is on the range of 0.37% over untreated wood.  On your end tag (probably back of), there'll be a AWPA use category and subsequently a retention level from the mfg.  It's in lb/cu. ft if you want to count pennies.  It's more an important number to figure out what type of fastener you should use.

Well...according to your figures, Packard's 4x4's are only way half thru the drying process at a weight of 4.625 lb/ft. The theoretical mid point is 4.865 lb/ft...so there's a lot of wood movement time left.  [smile]

 

[Michael Kellough]

[member=74278]Packard[/member] I don’t know if a cedar post will be an adequate substitute for Doug fir or yellow pine.
Like Cheese said, check other supplies and get something that is mostly dry that remains straight enough.

Then there is the problem of how to fix/secure the elevation of the replacement post the old hole…

Tom’s pea gravel fill for mailbox posts sounds very good, especially in combination with Cheese’s underbody coating advice. I think the combination would even work with very wet wood assuming you could dry the surface enough to get the coating to stick.

 

[Packard]

I have the post sitting out in the sun now.  Are we talking about days, weeks or months to dry out?

I should mention that my deck is about 12 feet above ground, and a fall off the railing would land me about 30 feet down a slope.  No setting into the ground.  Fastening to the deck boards and the overhead eaves only. 

I would use railing level posts if the soffits did not have a 4” x 4” opening to accept the posts.  The empty openings (2 posts) would look silly. 

I cannot get far enough back to get a photo that would show the application.  I will try looking up and see if that will show how it is used.

And this is for the stairway from the deck to the ground level back yard.