2x12 as landing pad for stair stringers?

I am building wood steps outside of an extension. I built my platform and now I cut my stringers. I know I need a landing pad for the stringers to rest on.

All of the resources I read talk about concrete landing pads. I seem to remember someone on here saying a PT 2x12 would be fine too.

I have two pieces of 2x12 left from my job. Both about 3.5 feet long. I screwed them together. So, now I have a nice hunk of 3 inch thick wood. 3.5 feet by 11.5 inches.

I dont see why this cant take the place of concrete. Is there any reason I should not use this?

Is there anything else I need to know if I do use it?

 

If it's laying on dirt, wood rots, concrete doesn't. Pour a 3" thick concrete pad for the landing and use redheads or tapcon screws to anchor a 2X12 to it. That give you a wood member to attach your stair stringers to.

 

I think you could get by with the PT 2X12. I have PT all over as banding around a walkway, as posts in the ground and as border for raised flower beds. All of it is around 20 years old and none of it has rotted.
I have read posts that say the "new" PT doesn't last as long as the old CCA treated stuff. I don't think the new stuff has been around long enough to make that call.
In any case, what's the worse that could happen? Ten years from now, you might have to replace it again?

 

In an effort to make life easy (at least short term) I used the 2x12s. I agree I have seen posts in the ground for many many years with no rot, which brings me to another question...

Lastyear I was driving by a house that was removing an older stockade fance and installing a new vinyl fence. At the curb for garbage was all the fence, including the 4x4s. I said GREAT look at all these 4x4s. You never know when you need to put up a small fence , make a raised garden, etc. So I took them - about 10 of them in all.

Well, when building my stairs I used two of them as my posts for the platform (the other side of the platform is attached to the house).

Then, as I was notching one out for a stair stringer I noticed that the inside didnt have that greenish tint that PT wood always seems to have.

Now, I knoow these 4x4s were in the ground. They were used a s afence and the dirt marks were still on them. I know they were at least several years old based on the greyish coloring and overall appearance of the fence.

Is it possible these are not PT? There was no rot whatsoever even though they had clearly been in dirt for quite a while, yet the lack of the greenish tint made me wonder.

 

No they are pressure treated. If they were untreated softwood they wouldn't last more than a couple of years (if that). I think on bigger lumber the treatment doesn't get full penetration. My guess is that the outer surfaces are protected and that prevents rot from getting to the middle.

 

Thats good to hear because I dug them about 5 feet into the ground and already built the platform on them.