Deck Piers Appear Unsafe 1

[BigfootBuildDecks]

What would you guys do about these piers? They are too small for the post in my opinion and even worse, they were poured directly onto an old footing that sticks out above grade. I want to make sure the deck is safe for my customers but I haven’t found any solutions I feel comfortable with. Could new concrete around the pier with rebar and epoxy into old footing and into pier with a rebar cage around the pier all tied together work? I would use a concrete bonding agent as well. The old footing is about 30 years old, my concern is that I don’t know if the pier is properly connected to it.

 

[phamENG]

The lower pier is a bit sketchy, but everything else actually looks like a decent build. Post bases under the posts to poured concrete piers (no indication of what the piers sit on - maybe go down to a spread footing? That's uncommon but so are many of the other details I see here), post caps at the second floor post to beam connections, lateral bracing under the deck.

Whole thing looks above average to me. Granted, average around here is still "somebody could probably die on that"...but it's something.

If you want opinions about the foundations, provide pictures of the foundations, please. The only one that's fully visible is the middle one, and I agree that needs some help.

 

[JoelTXCive]

The center one looks sketchy to me. I think it's just a CMU deck block from Home Depot or Lowes.

Even though the left and right piers are smaller, they might be okay. You would have to know the reinforcement setup and also how deep they go. Also, are they straight shafts or bell bottomed?

As an engineer, I always worry about the ledger board connecting the deck to the house. That's where the scary failures happen.

 

[phamENG]

As an engineer, I always worry about the ledger board connecting the deck to the house. That's where the scary failures happen.

Too true.

Also, just I just noticed the knee braces. Those are generally discouraged on end posts as the imbalance puts a moment into the post that can be hard to handle in a slender post.

 

[gte447f]

Bigfoot, I can't really see what you are talking about. Do you have a close up photo of the pier foundations about which you are concerned? The middle one looks sketchy to me. I can't tell what it is? The two outside ones look like sonotubes embedded in the ground. Assuming they are embedded a decent distance below grade, they should be fine, but they may be a little undersized (diameter) depending on the tributary area and the soil capacity.

 

[Enginerdad]

JoelTXCive, it's pretty unlikely that residential deck piers are reinforced.

 

[RPGs]

I always worry about the ledger board connecting the deck to the house.

Especially to a cantilevered floor platform. Easiest way to snag a code violation in my area. They are predatory about that stuff.

Bigfoot, send some pictures of the footings supporting the small piers if you have them.

 

[JStructsteel]

Looks ok to me. What are those footings supporting, 2-3Kips? even plain concrete should handle that.

If absolutely concerned, hire a local professional to evaluate, and make a design recommendation.

 

[HouseBoy]

"As an engineer, I always worry about the ledger board connecting the deck to the house. That's where the scary failures happen."
I second that concern ESPECIALLY in this case where the second floor joists are cantilevered!
I wouldn't expect the cantilevered joists to be adequate but a greater concern is - HOW IS THE EXISTING RIM CONNECTED ??

 

[phamENG]

I second that concern ESPECIALLY in this case where the second floor joists are cantilevered!

Holy cow! How did I miss that? Yikes. Yeah. That's no good.

 

[LittleInch]

The basic goal post type frame supporting the upper deck actually looks like the strongest part of the system.

I would imagine the main deck boards are at best nailed to it or just use gravity to hold it in place?

Deck failures can be sudden and catastrophic, but foundations don't tend to do this.

The connection of the deck back beam to the building is critical as is the fixing of the cross members on which the deck boards sit.

Much worse is the two bolt connection of some fairly spindly looking posts holding the fencing up. This gets a load of abuse from people sitting on it, leaning on it, falling into it and if it breaks at the high moment area the person falls several feet.

Also is a massive looking chiminea / pizza oven? on a wooden deck a great idea?

If you need more ideas about the foundations we need a better set of pictures....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[gte447f]

LittleInch,

"the deck back beam to the building" = ledger board
"the cross members on which the deck boards sit" = joists

"Much worse is the two bolt connection of some fairly spindly looking posts holding the fencing up. This gets a load of abuse from people sitting on it, leaning on it, falling into it and if it breaks at the high moment area the person falls several feet."

... Assuming this connection is installed correctly with the appropriate hardware, this is a standard connection that has been lab tested and proven to adequately resist code required lateral loads on the guardrail. The appropriate hardware consists of tension tie devices fastened to the deck joists on the backside of the rim joist. I can't say whether the connections are installed correctly with appropriate hardware, because I can only see the outside elevation of the connection in the photo, but 2 bolts and 4x4 posts are standard and are no reason for alarm or to question the adequacy of the guardrail.

 

[LittleInch]

Point taken, I was being descriptive rather than using the correct terms.

If they are 4 x 4's then Ok, I'll give you that, but the issue is usually how long they have been there and what condition they are in. Hidden rot and moisture trap can easily occur on those posts just where they have the highest loading. we don't have any dimensions of anything so it's all a bit of a guess from one photo. There is then the issue of how well that front board is actually fixed to the joists which is what is giving it the connection into the deck superstructure.

I think I've seen too many posts here on deck failures over the years.....

Some parts of this system look new and fairly well put together and other bits look recycled or a lot older.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[manstrom]

the posts are pinned / fixed at the top and pinned at the lower floor. The footing can't roll even if you considered it fixed because the floors are bracing it.