Deck Stairs Rotten

[Zerk]

I used the same trick but instead of using galvanized tin I used felt paper. In the many pole barns I built, I learned early on that the roof would sweat with water running down on my 2x8 rafters causing them to rot.
er.

Contractor who just built mine put plastic between metal and trusses, for this reason. He told me to use pressure treated wood at the floor, becaus concrete sweats. I read about poles rotting out.

The other pole barn built around 1985 has foam board, which may be the reason. Though you can see some of the trusses have water stains. Dirt floor and poles look fine.

 

[Zerk]

It's the crappy treating process/chemicals. For some reason the good CCA chemicals of old were outlawed, EPA? No 2X material is now rated for "ground contact", you need to go up to a "timber" size material, possibly 4x4 & up but I'm pretty sure that a 6x6 is rated for ground contact but that does not help you with your stair stringer. I have a 4 year old picnic table & the PT "leg" is rotted where it touches the ground:confused2: I guess that the EPA wants us to go back to dipping/painting our lumber in crankcase & diesel oil every few years.

4x4 are rated for ground contact, most likely because they are used for decks. But ya, I wish they stock 2x6s for ground contact.


Though if you paint the wood, it will last a long time. Look at homes.

 

[N80]

When is the last time you used a hand saw?

I use a handsaw all the time. There are plenty of jobs for which a handsaw is the right tool, the finish cut on stair stringers being one of them. But I agree, that was not the cause of the rot. The cause of the rot was improper screw placement splitting the stringer.

 

[Zerk]

Maybe, but I am not 100% convinced on that. Maybe the paint or stain didn't get in the crack, that is possible. The idea the crack created a pocket for water, I dunno. Stairs have many horizontal surfaces. But I have not seen it myself, I am just a skeptical person.

I've done a lot of building the last few years, so have to see how my stuff goess. I question the new pressure treated wood. If it was better, the government would not have needed to force it on us.

You are done south, so I am guessing salt wasn't it. Up north that would have been a top guess.

 

[ultrarunner]

In 1990 I did a board fence with 4x4 green treated posts from Home Club... the posts are perfect.

In 2005 I added a section and used brown treated posts... they are starting to go.

 

[TomSeller]

Some good advice here - but what ever happened to the treated lumber that was supposed to last a hundred years? Not that it ever did but it was better than it is now,,,.

Well we get 100 year floods and storms every 4 or 5 years nowadays so the lumber manufacturers figured they would shorten up the 100 year wood life too.

Paint did not help, it traps moisture. Not treating the cut was a green light to the problem.

 

[ultrarunner]

Before Pressure Treated I only used Heart Redwood and it worked OK.

I recently replaced a few treads for a neighbor and he bought heart redwood... never did find out what it cost... he just said EXPENSIVE

A friend I grew up with lives off grid in a redwood forest and just built a small shop 20x20... he felled a Redwood Tree, tossed any "White" wood and milled the rest for his shop... his father in law has a porta mill.

When I say the quality of the lumber I said a guy could go broke fast... he said it was FREE outside his labor.

 

[N80]

Maybe, but I am not 100% convinced on that. Maybe the paint or stain didn't get in the crack, that is possible. The idea the crack created a pocket for water, I dunno.

There is a pretty good correlation between the areas that are starting to rot on the remaining stringers and where the screws split the wood. In places where the wood is not split there is little or no decay. The quality of the lumber is likely the prime culprit but I believe the split areas are the catalyst. If not then it will remain a mystery. And, there is no paint or stain on the stringers other than on the outside edge of the one that rotted out. The paint was purely for looks.

You are done south, so I am guessing salt wasn't it.

No salt but high daily humidity and this back part of the house does not get much sun.

For me, the take home story is that the current average big box store treated lumber is not going to last like that wet, heavy green stuff used to and that if you don't do everything just right with it you're going to get 4-5 years out of it. This will definitely affect future projects in my mind. Unfortunately I just completed a small deck (8'x 18') on the back of my cabin using this yellow stuff. We did stain it.

 

[N80]

Before Pressure Treated I only used Heart Redwood and it worked OK.

My father-in-law built the extensive decking around his house out of redwood nearly 40 years ago. About 5 years ago it was starting to rot in places and was looking bad. He removed it all but was able to plane down about 75% of it and reuse it. It looks good again now and I'd guess he'll get another 10 years out of it. So 50 years is not too bad.

Red cedar is the thing around here but it has to be old with plenty of red heart wood. I have an old barn on my property. I'd say it is at least 75 years old. It is slowly falling in but the main support posts are red cedar stuck right in the ground and they are still solid. You can see where they trimmed the white outside wood away at the bottoms so nothing but the red heart wood goes into the ground. The local farmers do this for their fence posts too. Unfortunately it is getting hard to find cedars old enough to have enough heartwood for this type of duty.

 

[EddieWalker]

Without seeing it myself, I find it hard to believe that the opening created by the wood cracking would have anything to do with it rotting. The pressure treating process easily gets all the way through a 2x piece of lumber. Rot is caused by mold growing on the wood. The mold needs moisture, heat and food to survive. The treatment process is supposed to remove it as a food source, but like you said, it isn't like it used to be. If there is enough moisture there long enough, it breaks down the chemicals in the wood and it becomes food for mold. The problem is you have too much moisture there. If it was properly ventilated, the additional surface area created by the crack in the wood shouldn't matter one way or another. I've seen way too many cracked boards without any rot to believe this. I've also see a lot of rot on nearly new decks that didn't have any ventilation. Air flow is the key to keeping lumber dry, and how long it lasts.