Steel deck posts

[Wiebster]

I’m building a deck off of my second floor shop and was seriously considering using steel tubing as the posts instead of pt 6x6’s. They would be 5”x5” square and 11 ga thick. The posts would be around 13’ tall. My question is what sort of a bracket would you weld on top to securely hold the beam to support the joists? Do you leave gaps at the bottom to drain any condensation or collected water or try to weld them up air tight. Any thoughts would be greatly appreciated especially if you’ve actually done this and are not sitting in a lazyboy drinking beer and spewing nonsense.

 

[JuncleJohn]

Not an expert, but I’d weld them up solid. Horizontal brackets with gussets. You will want to bolt all the way through with a steel plate on the back side.

At least that’s how I’d do it.

John

 

[Shiftless]

not sitting in a lazyboy drinking beer and spewing nonsense.

you got me on 2 out of 3

 

[tarmy]

I made my steel posts…works great. I wanted smaller post due to the view…

 

[kmacht]

What’s the advantage? I can’t imagine that a 5x5 steel tube is cheaper or easier to install than a 6x6 wood post. If the rest of the deck is wood then why steel for the posts?

 

[JuncleJohn]

I’ve seen treated posts severely warped in the past.

John

 

[readhead]

I was a structural fabricator for over twenty years. 5x5 is fine but for that length I would go 3/16”. Look at a Simpson catalog for typical applications for the top of the column. Will you weld to an embedded baseplate or use a baseplate to bolt down to the concrete?

 

[jack stand]

I'd absolutely provide a small vent down at the bottom. I've seen years of condensation build up and show the consequences when it's accumulated long enough to swell a 2x2x.25 sq tube when it freezes. I've also seen 2" black pipe on more than one set of ladder racks on a pickup have one of the "legs" actually swell to the point of bursting.
It takes a while, but the whole point of going with steel is hopefully outlasting today's pretty lame PT lumber.
Even if you're in the desert there's no downside to a small 1/4-3/8 vent hole.

 

[Ultradog MN]

I’m building a deck off of my second floor shop and was seriously considering using steel tubing as the posts instead of pt 6x6’s. They would be 5”x5” square and 11 ga thick. The posts would be around 13’ tall. My question is what sort of a bracket would you weld on top to securely hold the beam to support the joists? Do you leave gaps at the bottom to drain any condensation or collected water or try to weld them up air tight. Any thoughts would be greatly appreciated especially if you’ve actually done this and are not sitting in a lazyboy drinking beer and spewing nonsense.

Not to steal your thread but...
Did someone mention steel and deck in the same sentence?

 

[nadogail]

IMHO, Schedule 40 pipe 2” or larger will take a lot of load in direct compression.
For a single porch or deck I would probably use the heavy Simpson brackets.
Having a Stick Welder solves a lot of problems.

 

[strutaeng]

For the base connection, you can do it two ways as used in commercial construction:

4 cast-in-place bolts with leveling nuts for plumbness adjustability. This is usually used on building main columns. The baseplates are recessed about 8" on a diamond leave-out. After erection, they grout the underside with non-shrink grout, then they'll come and fill that with concrete and leaves a nice finish w/o bolts exposed. Drill a hole on the bottom of the post at grade elevation, then fill it with non-shrink grout. Any condensation will weep out.

Another way is to have the bolts exposed like they do on lightpoles. Just as before, but not recessing the bolts.

On our projects we have a note that tells the contractor to use a plywood template matching the baseplate to set the anchor bolts.

Different ways to do the top as well.

1. A single vertical shear tab down the center of the wood beams with holes punched out for bolts would look very clean. You'll have to kerf the wood beam the thickness of the shear tab.
2. angles to act as corbels will also work, but you still have to brace the beam so it doesn't rotate and won't look as clean.

Basically, many ways to skin a cat...

5-6" steel tube seems appropriate for this, and will look nice and be close to a 4" nominal wide wood beam (I'm assuming you are using wood beams, right?). 2" is way too slender. Even it works (I doubt it), it will look like linguini and scale would be off.

 

[dcg9381]

I’m building a deck off of my second floor shop and was seriously considering using steel tubing as the posts instead of pt 6x6’s. They would be 5”x5” square and 11 ga thick. The posts would be around 13’ tall. My question is what sort of a bracket would you weld on top to securely hold the beam to support the joists? Do you leave gaps at the bottom to drain any condensation or collected water or try to weld them up air tight. Any thoughts would be greatly appreciated especially if you’ve actually done this and are not sitting in a lazyboy drinking beer and spewing

I used steel posts. Wood decks in Texas have very limited lifespans, so I built with steel. Absolutely no regrets.. I think the only thing I'd change is that I'd go back and paint them with catalytic automotive type paint. I did prime them with epoxy.

I had the hangers custom built for the LVLs that run on top of the deck. I did 2-D cad drawings and used the company below. At the time, I want to say $55 per bracket or so. Totally worth it. Not a local company, they shipped them to me.

I did not cap them..Capping them would be a good idea.

 

[jbfab]

I've been in the steel industry for >25 years now. For joist attachment I would recommend a seated connection with a knife plate. We don't typically put vent holes in, but personally I don't think it's a bad idea.

 

[My Old Tools]

I would go the rest of the way and use C-channel for the joists and beam. Weld it all.