top plate on steel beam

[JStructsteel]

When replacing a load bearing wall with a steel beam, how thick of a top plate on the beam do you use? I have used just a single 2x before, but had a few contractors ask if they can do a double top plate.

For a roof, I get it to nail any uplift brackets. For a floor, any advantage other than fastening?

What do you folks spec?

Usually I thru bolt too with 1/2" bolts on a staggered pattern, 18" o.c.

 

[sdz]

Do you mean a timber top plate on top of the steel beam? How about a diagram?

 

[XR250]

I always specify a single top plate. A double would also work if they request it.

 

[JStructsteel]

Do you mean a timber top plate on top of the steel beam? How about a diagram?

Yes, a 2x fastened to the beam.

 

[EngDM]

We have done both single and double nailers. One advantage would be to get increased capacity when taking the base shear out of the plates and into the bolts (you'd be doubling your area) without needing to increase the # of bolts. Other times we've added plates to maintain an elevation, sometimes the steel needs to be at a certain elevation etc.

 

[W460x68]

Our standard which gets spec'd probably 90% of the time is a single 2x top plate with 1/2" bolts staggered at 24". I could see using a double plate if you needed more capacity out of that connection, or trying to make a specific elevation work.

 

[Brad805]

At one time we always used a single 2"x_ nailer, but lately we have been using double nailers to allow for more options for tie downs or better connections between the joists and beam.

 

[KootK]

This is surely pretty minor but, where space allows, I've had contractors want to nail a second plate to the bolted lower plate so that there is less potential for bolt interference with the existing framing that the beam gets placed up against.

 

[phamENG]

Downside to double top plate is the increased potential for shrinkage. You may be putting wood that's 18% or 19% into a house where the rest of the wood is already down to 8%. The more plates you have dropping that 10%, the more you invite cracks in finishes.

 

[KootK]

Downside to double top plate is the increased potential for shrinkage. You may be putting wood that's 18% or 19% into a house where the rest of the wood is already down to 8%. The more plates you have dropping that 10%, the more you invite cracks in finishes.

I certainly agree but, at the same time, I feel that there winds up being a lot of things about this situation that invite cracking in supported finishes. Recently, I've taken to telling the owner that there is some risk of finish cracking on anything we touch that might be supporting existing stuff above. Even the removal of non-bearing walls. The contractors that bring be on sometimes don't love that but, once I explain that it is risk mitigation for them too, it seems to land pretty well. Anybody else doing similar things?

 

[phamENG]

Anybody else doing similar things?

Always. Something to effect of "Removing load bearing elements, adding loads, or otherwise altering the structure may result in cracking finishing, door and window alignment issues, and other serviceability problems. Owner is advised to provide an appropriate contingency for repair."

I usually try to put it in my proposals upfront, along with wording that architects or contractors (who usually hire me) are obligated to pass this information on to the owner and explain it to them, or provide me with an opportunity to explain it.

 

[XR250]

I've had contractors want to nail a second plate to the bolted lower plate so that there is less potential for bolt interference with the existing framing that the beam gets placed up against.

Most of the folks around here use carriage bolts and either crank the shit out them to pull them flush or they countersink them.

 

[SE2607]

When replacing a load bearing wall with a steel beam, how thick of a top plate on the beam do you use? I have used just a single 2x before, but had a few contractors ask if they can do a double top plate.

For a roof, I get it to nail any uplift brackets. For a floor, any advantage other than fastening?

What do you folks spec?

Usually I thru bolt too with 1/2" bolts on a staggered pattern, 18" o.c.

For a dropped beam, I used a 4x nailer with welded studs dapped into the 4x, leaving at least 1-1/2" meat, so that they don't interfere with the joists. If the depth is architecturally obtrusive, I use a 2x with Simpson TF screws, but that requires the flange thickness to be no more than 15/32". For a flush beam, I've struggled with this. When I have 2x10 floor joists and want to use a W8 beam, I usually have less than 1-1/2" for a nailer which is what is required for a top flange hanger. I usually end up with no nailer and welding the top flange hangers or using #10 SMS. The contractors I work with like welded studs over the screws because the steel beam comes with them already attached using an automated process in the shop, but I still require a 4x nailer which usually negates that approach. They don't like the screws because they easily break off, but, after running through the other options, I usually get what I want. I NEVER through bolt. That reduces the strength of the beam and I don't want to calculate how much of a reduction it is. It's a business decision. Also, I've taught the contractors I work with to not drill any holes in flanges for ANY reason, so, if I violate my own rule, they will use that as a precedent.

Other than that, I don't have much of an opinion on the subject.