What you might not know about pressure treated wood:
1-They are not all the same
2-PCF rating on the end tag
3-Above ground use does not mean it can be used for ground level decks even if there is no ground contact
4-Warranty is for product replacement only..no labor for removal/re-install or hauling away
5-Local home improvement stores do not provide you with the knowlege you need.....just because the lumber is for outdoor decking...may not be suitable for you application
6-A little black coloring in your wood might lead to soft and spongy in just a few months
See my 4 year "new" deck picture below:

Yes very few people know that there is different types of pressure treated material. As a rule most support post 4X4, 6X6, 6X8 and so on are treated for ground contact. There is still a difference for ground contact below ground contact absorbtion. I have never see any 2X material for ground contact or below surface ground contact. Regular decking material (2X, 1X's) is not meant to be placed on or near the ground. It appears that yours was ground contact or close proximity to the ground. A rule of thumb is at least 12" of clearence from the ground for adequate ventilation to avoid a constant moisture saturation.

Most contractors are aware of the difference and will build accordingly.


Retention level refers to the amount of preservative that remains in the wood after the treatment process is complete. It is measured on a weight basis and is typically expressed as pounds of preservative per cubic foot (pcf) of wood.

There are a number of typical retention levels available. Generally, the harsher the condition the wood is exposed to, the higher the retention level must be

Higher chemical content refers to wood for ground contact with specified retention levels greater than

0.40 pcf for ACQ
0.34 pcf for MCQ
0.21 pcf for CA-B
0.15 pcf for CA-C and MCA, or
0.14 pcf for μCA-C.

While on the subject of pressure treated lumber there is also precautions that need to be taken concerning the fastners used. The newer pressure treated lumber will corrode most fastners ( nails, screws and hangers) if they do not have a protective coating (galvanization) the best of which is a hot dip method rather than electrogalvanization.

There is some good information on these subjects that can be found @ http://www.finehomebuilding.co...ated-wood-decks.aspx

This message has been edited. Last edited by: redoverfarm,

I've even seen the galvinized screws rust off within a year. I've switched to ceramic coated, cheaper then stainless and are not as soft so you get less cam outs.
That deck failing is not the fault of the wood, it's all on the builder.
Removing the top soil laying down some geo cloth, some #57 stone and building it so it was sitting on 4 X 4 so the rim joist were at least a few inches of the ground would have gone a long way to at least giving it 1/2 a chance.
Ever take the time to read the tag on a landscape timber?
It says not for below ground use. So what does everyone do? Sets them on the ground then back fills with dirt or mulch. So now it's below ground. That's why they rot out.
Use 4 X 4, 4 X 6 or 6 X 6's and there going to out last them by at least 10 times, plus there less tippy.

Yikes. Did you really fall through?

Since your deck is built right on the ground I would have opted to do a patio instead of a wooden deck. A paver patio is a DIY-able project if you are in reasonable shape. If you need to hire the work out a stamped concrete patio looks great and has a long life. At grade IMHO a patio is a much better option with lower maintenance and a much longer life.

if there isn't air moving underneath it, it's not a deck, in my book.

nicest deck I ever was was on a house cut into the side of a hill, so the deck was up on timbers and the bottom was high enough to walk in. so there was a wonderful storage, potting, and work space underneath that thing. put a little tarping up over the lattice, and most winter days, you could do a little workshop stuff under there with just a milkhouse heater.

and the cats could keep the rodents down without getting into the real wind and cold.