Will my support beam out of stacked 2x4's be strong enough?

Started by Charles_PL, December 28, 2020, 07:16:48 AM

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Hi all, my project is to open up the wall and replace the 2x4 studs with 2 metal posts that supports a stacked 2x4 beam.
For now, I have 3 inch screws at every ft between every 2x4's for the beam. Here are visuals:

Picture: https://ibb.co/ZWyJdQJ
Diagram: https://ibb.co/4TXLBX9

However, I am reconsidering all of this as I am not sure if this will be strong enough.

What do you guys think?

- I reused the old 2x4 (7.5ft) studs to build the beam
- This room is on the top floor and the roof is flat
- I did not use glue
- I prefer to assume the ceiling is not anchored to the bricks



My first question is do those new metal supports carry through down to a footer, and secondly (an observation), laying 2X material on its side is not the strongest way to do things.


Flat stacked 2x4's do not make much of a beam unless it is a factory-made glue-laminated beam, like a real Glulam beam. Glu lams are engineered with stronger lumber in the upper and lower layers and high strength glue applied under controlled conditions, etc. A home made layered beam would be using 2x material turned on edge like this....

Note that the splices are placed directly over the support.

I can't say much more than that as I have no idea what is above, if the ceiling joists rest on the brick wall or not or what is below the floor accepting the load from those steel posts.
Just because something has been done and has not failed, doesn't mean it is good design.


What the others have said.
First, a stud is #3 grade, not a strong stick in bending.

Second a glulam is a tested assembly. What you are trying to do when making a beam like that is restrain the horizontal shear between layers. Regular screws are not used in framing because they have no shear strength, here they are in a shear critical application.

The way to look at the bending strength of these beams is it is no different in bending strength than laying 4 2x4's side by side rather than as a 4x6. We can look but it is less than half strength and is likely inadequate even at full dimension.

As the others have said figure out your loads being supported and then trace a complete load path to the foundation, what is supporting those posts under the floor?


Thank you for your answers!

The metal supports are sitting on the same base as the old studs.

Perfect, I will look into the glulam beam. I didn't think the screws had no shear strength.

I originally screwed the 2x4's flat as the assembly was easier.


It does not matter if the posts sit where the old ones were, you are gathering and concentrating more load. It is not uncommon to find that in the original construction the framers failed to stack the framing, it works with light loading and is generally allowed in 16" on center redundant framing. When you concentrate loads that can be a whole 'nuther ball o wax. Trace and quantify the loads from above, beam adequately and follow those loads safely through the framing to the foundation. Assume nothing, the moment I assume, Mr Murphy has entered the building  :D


Quote from: Charles_PL on December 29, 2020, 01:04:29 PM

Perfect, I will look into the glulam beam. I didn't think the screws had no shear strength.

The ever so common "deck" screws are brittle as they are hardened to prevent tear out of the driven head. There are screws that are structurally rated; they will be labeled as such. Simpson makes a series of screw that are designed to be used with their metal joists hangers, for example. There are others as well.
Just because something has been done and has not failed, doesn't mean it is good design.


The problem is you did zero research on the proper solutions.

You also don't seem to care about what is supporting your posts, either your two new metal ones or the existing ones on the ends.


Why not box around the jack-posts and leave in place?