End support for residential Steel I-Beam
I have several 8″ Steel I-beams in the ceiling of my walkout basement supporting the upper floors of my 12 year-old house. Being a walkout, one end of the beams is supported about 4 feet above the foundation wall. (In the area in question, the foundation extends about 4 feet above the basement floor and the beams are, obviously, at the ceiling.)
The basement wall is framed with 2 X 6’s and the end of the beams are supported only by three 2 X 6’s nailed together and positioned beneath it and atop the foundation wall. There is no blocking between these 2 X 6’s and adjacent wall members. The house is sheathed with insulated panels. I am concerned that these 2 X 6’s are not sufficient to support this beam permanently.
The three 2 X 6’s have separated slightly (perhaps an 8th inch) and developed a slight bow.
I have two questions: 1) what would have been the right way to support these beams originally and 2) what is the best solution today?
Replies
I see nothing wrong with the ganged 2x6s. Four would have been better but I am assuming three covers the entire width of the beam. Blocking it would have been nice considering the use of ISPs but I assume with a 4' height it passed inspection that way.
I like steel support members, not wood, when using steel beams. My brother in law is a steelworker and sets them for me. I show up and the bottom plate (usually 6x6) is welded to the base of a 4x4 square steel support. We hammer drill the foundation and place malleable anchors in exactly where they need to be. Bolt it up and make sure it is shimmed (with these really neat horseshoe shaped plastic shims) until true. Crank it down. Cut the columns to height and hoist the beam. The steel column is welded to the bottom of the beam. In my house, I have a 10" beam that runs 28 feet between the steel supports. The local BI has no probs with it and was actually amazed at the rigidity of the stand alone structure before we pounded a single nail.
Does it cost more than a gang of 2Xs? Yup. Is it ever going anywhere? Nope
Mike O.
No way to tell if the 2X6s are adequate without determining how much load the beam is carrying.
I also like steel posts to carry steel, as Mike mentioned. If this bothers you, look into getting a steel posts and replacing the 2X6s. Don't get one of the $15 ones from the big bozes - Get a serious one from some place that sells I-beams.
Why don't you ever see the headline "Psychic Wins Lottery"?
if you could now add the blocking and maybe a layer of 1/2" ply, it would certainly 'stop the rot' as it were. and certainly ease your mind!
good luck
Bosshog is right. Without knowing the loads you cannot know if the 2x6's are adequate. Always try to support steel with steel and wood with wood if possible. They both change the same (moisture for wood and temp. for steel). A good practice is to always set joists on a wood plate that is attached to a steel beam. The plate and the joists will shrink and expand at similar rates (not the exact same amount since the grain is in a different orintation but better than steel only). Steel can carry a great deal of load that will crush the wood fibers. If you can't use a steel post you should at least use a solid timber post. Nailed together 2x's are not a recommend practice (bolted can work) since the nail's withdrawal strength is very limited (when the built-up piece is loaded it wants to bow and the nails will allow each member to separate).
I am afraid I can offer no firm data on the load… It is a two-story house. A steel post supports the beam 12 feet from the end in question. The floor joists on top of the beam are 2 x 10s, 16"oc, and span 10 feet in both direction perpendicular to the beam.
My instinct says that something is not right here.
Now don't go into a panic and start losing sleep. It's had the twelve year test but I think it would be well to invite an engineer or a good framer familiar with an engineer to take a look at this. We can't see too much through this little phone cord at the back of the PC.
The reason for using a steel beam is normally because we want to avoid having the area punctuated by posts. The fact that somebody placed a post there tells me that they didn't size the beam correctly or didn't have confidence in the engineering of it. The fact that some of the 2x6s are bowing further substantiates this. Maybe the beam is sized right and when they saw the bowed 2x6s, they added the post for insurance instead of stabilizing the end support which can easily be done by pulling them together with clamps, adding more meat to the column, and blocking it to the adjacent studs. If the steel midpoint post is an after thought, then there is no planned support in the slab for it and fracturing of the concrete is a possibility, though a slim one.
An engineer on site can easily diagnose and recommend. We are just guessing.
Excellence is its own reward!