What Caused This Wood Deck Failure?

[bdhsfz6]

I doubt you actually did anything that caused it. Treated wood today just doesn't last. I'm finding yellow wood doesn't last as long as other brands of treated wood.
I have some yellow treated wood on my deck that has rotted, while treated wood of a different brand (from Lowes) is still good and it's right next to each other

Carpenter Bees seem to love the new treated wood while they avoided the older type. The deck joists I replaced a few years ago are riddled with their holes.

 

[oosik]

OK - I checked the average rain/snow water accumulation for the Spokane, WA area. It's - 16.93 inches. I'm somewhat less than that here. 2023 - 12.84 inches. I have a Davis Vantage Pro 2 to measure rain fall/snow conversion.

Still it's enough to grow the gigantic Ponderosa pines I have here.

 

[jyoutz]

OK - I checked the average rain/snow water accumulation for the Spokane, WA area. It's - 16.93 inches. I'm somewhat less than that here. 2023 - 12.84 inches. I have a Davis Vantage Pro 2 to measure rain fall/snow conversion.

Still it's enough to grow the gigantic Ponderosa pines I have here.

You must have soils with great fertility and good water holding capacity. 17” is on the lower end of ponderosa pine growth needs. I would bet the decadal precipitation average is higher than 13”.

 

[pmsmechanic]

Have you ever considered extending your concrete deck towards the slope and building a retaining wall? You could have a nice raised garden or a flower bed on the edge of the retaining wall and you'd have enough area or a table and chairs. Just a thought vs spending money on something that might rot away again in a few years. The trade off would be that you once again have steps in a awkward place because the door placement isn't ideal for that deck. Just my thoughts.

 

[MH8675309]

I would have thought the concrete slab underneath would be somewhat of a moisture barrier?
View attachment 875817

With a layer of visqueen underneath it might be. It is amazing how much moisture can surface on concrete especially when it warms up - even with a layer of visqueen

 

[NoTrespassing]

Project #1 of 3

update pics

www.tractorbynet.com

Built this porch 20 years ago and there has been zero rot. It has lattice around the bottom now and railings were added 12 years ago when my son was born. We've probably stained it 3 times over the years. It's built over dirt and I'm sure the roof helps.

 

[2manyrocks]

Runner's patio would be nice with a roof. Even if a roof isn't being added at this point, might think about making sure that any additional concrete has adequate footers to support posts for a roof if he decides to add one later.

 

[kenmac]

Carpenter Bees seem to love the new treated wood while they avoided the older type. The deck joists I replaced a few years ago are riddled with their holes.

That treated wood seems to attract those bees, while they don't seem to bother regular wood in my barn !

 

[Runner]

Replaced the missing siding yesterday and this morning the deck went bye-bye in the dumpster. Next will build a little more permanent stair/landing. Going to try to re-use some of the good pieces of lumber reclaimed from the old deck (yes, there actually were a few, mostly deck boards and guardrail pieces).

Discovered another occupation I don't want to be - siding installer...

 

[bdhsfz6]

That treated wood seems to attract those bees, while they don't seem to bother regular wood in my barn !

At the risk of derailing the OP's thread, try one of these traps:

Amazon.com

Swat one and put it in the jar as bait. Hang it in a sunny area near where the bees are active.