Residential Steel Beams

By
©1993-2012 Tim Carter

        
Summary: Steel I beams can be used on residential construction. However a steel beam design might require special handling. Structural steel beams are heavier then wooden beams. Consider the cost of special cranes and steel beam prices when using steel beams.

DEAR TIM: My house plan calls for steel beams that will support the floor joists and even parts of a brick wall. Can I substitute wood beams for steel? Is a steel I beam hard to handle on the jobsite? Do you think I can install one with some friends? How can you get the best steel beam prices as my budget is pretty tight? If I find a used steel beam, do you see any problems incorporating that into my new home? Steve B., Cinnaminson, NJ

DEAR STEVE: Steel I beams are pretty husky structural components used sparingly on a residential building site, because wood is the primary structural material found in most homes. However, steel is a ho-hum material on a commercial or industrial construction project as it’s the mainstay of these larger projects where wood is scorned because of its inherent fire danger and limited characteristics as buildings get big.

This custom home had multiple steel beams that intersected at 90-degree angles. Note how tall the beams are. PHOTO CREDIT: Tim Carter
This custom home had multiple steel beams that intersected at 90-degree angles. Note how tall the beams are. PHOTO CREDIT: Tim Carter
Architects and engineers employ steel beam design in homes for both beams and columns because it’s so strong. You can typically hold up the same loads with wood, but you need more of it and usually the size of a wood beam is much larger than a steel I beam, that’s holding up the same amount of weight. Termites and other wood-destroying insects don’t eat steel, so that’s a distinct advantage if you want certain parts of your home to remain standing.

You can substitute, in many cases, a wood beam for a structural steel beam. If you desire to do this, be sure you have a structural engineer, or an architect, specify the material and the needed supports. If you do use steel, pay close attention to the connection details at the steel beam support. The connections between the beam and columns must be secure.

I would never install masonry on a wood beam. There is too great a chance the wood will deflect and cause failures in the masonry. What’s more, it may be a building-code violation in your area.

Steel beams, as you might suspect, are heavy. Steel beam dimensions and sizes are not the same. You can have two different beams that are nearly identical in height and length, but one may weigh twice as much as the other beam. Typically, you’ll see beam sizes called out in numeric form like 8x17. Usually this means the steel beam is very close to 8 inches tall and weighs 17 pounds per lineal foot. This is a very common size found in many residential homes. But you can get 8-inch tall steel I beams that weigh over 35 pounds per foot. I installed 10x31 beams in the last house I built for myself.

But take a moment and do the math. Let’s say you have a ranch home and a 40-foot-long 8x17 beam is called for in the plans. You can have that beam delivered to your building site. Don’t try lifting it yourself, as it weighs almost 700 pounds. A smaller beam that long presents handling challenges as well because it will be like a wet piece of spaghetti when you pick it up with all your friends. If you’ve never handled beams before, it’s best to work with smaller ones before trying to handle long pieces of steel.

Steel is a commodity, and its price fluctuates. The current steel beam price you have to pay for new steel may not be bad as you might think. Currently, the market is depressed and supply may be far greater than demand. You may be pleasantly surprised to discover that you can purchase a construction steel beam for not much money.

You may be able to find decent steel beams from a demolition contractor who routinely salvages them from buildings. They sell them for scrap, so the price you pay will usually be much less than that of a new beam. However, you have all sorts of challenges when dealing with used beams. You might not get the exact size you need, the beams can be bent and you have to figure out how to transport it to your job site. My guess is a demolition contractor is not set up to do this for you. But stranger things have happened.

At the end of the day when you compare all the costs involved in obtaining a used beam instead of a new one, you may discover there’s not that much of a difference in price. In any event, be sure the beams you use are primed and painted to prevent or minimize rust.

If you decide to try to erect the steel yourself on a job site, be very aware of the dangers. The pockets in a poured concrete foundation are not that deep and if you’re not careful the beam can slide out of one end while you’re futzing with the other end of the beam.

To level beams in pockets you need solid-steel shims of different thicknesses. Never use wood shims, even treated lumber that is not supposed to rot. The heavy loads on the beam can compress the wood over time.

Steel beams can be blown over by wind if they are not secured. I’ve seen beams collapse after a rainstorm saturated clay soil causing it to expand and lift up columns that are supporting the beams. Hundreds of pounds of weight floating above your head and body on a construction site are never to be underestimated.

Author's Notes

I received the following email from James Calhoun, who is an Architect. He wrote:

"Tim, something you might want to know. Most municipality building codes do now allow used structural elements, like old steel beams, to be placed into new constructions without certifications by an Architect or Engineer (who in their right mind would do that...) or a serious (50%) devaluation of the rated structural capability of the member. Otherwise, you did a good piece on the advantages of steel in residential structures. I design steel for homes all the time."

Thanks, James.



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Comments:

Welcome! I, Tim Carter, don't answer questions here. If you post a question here in the Comments Area, perhaps another visitor will help you. You need to go to the Ask Tim page if you want a question answered. Once there, look closely at how many weeks behind we are. Please be patient as you use this free service. If you have an emergency and need to talk to me, there is an option there for you.
Brock
16 Feb 2010, 16:20
Twice in the past two years I have been able to open up kitchen and dining areas for clients by removing support columns or walls and using a steel beam to support the load. With a wood beam there would have had to be a lot more structural work to make room for the much larger height of a wood or engineered wood beam. The projects would have each taken a lot longer to complete and been a lot more expensive had I not used the steel beam for the span. Not something the average carpenter or builder seems to consider is the use of alternative approaches.
Donnie Andrews
01 Mar 2010, 19:48
Im wanting to build a bridge with steel I-beams and I need to know the thickness of the steel I would need if Im spanning 20ft and will have about 40,000 lbs of concrete on top.I am planning on using 4 beams,can anyone help?
Dwight Havens
24 Mar 2010, 11:02
Donnie, you really need to hire a structural engineer. A lot more goes into designing a bridge than just the support of the roadbed.
mark
26 Apr 2010, 19:21
i live in michigan i have a 1700 square foot colonial house with a basement that has a 7 inch steal i beam what i want to do is take down the bearing wall that is down the center of the house and put another steal i beam on top of the one of the one in the basement with a span of about 16 feet is this possible the plain is to give the house a open floor plan allowing the use of my dead space in the formal living room
and making the kichen large and open please let me know if this will work for me house was built in 1968
Stephen
06 Sep 2010, 22:18
I just finished a 3-car garage with an upstairs living area, using an exposed steel beam spanning about a 26 foot length in the garage. To my surprise, the building inspector required me to coat the beam and columns with a fire-resistant paint. Considering that this is a simple 2-coat latex paint product, does that make any sense at all? Won't the wood/drywall structure fail long before the steel does?
DALE CARSON
16 Oct 2010, 20:03
I WANT TO MOVE A POST IN MY BASEMENT. THE POST IS IN THE CENTER OF A 20' SPAN LONG, AND THE ROOM IS 20' WIDE. (20' X 20').
BY MY CALCULATIONS, THE POST SUPPORTS ABOUT 8000LBS.
A NEW POST WILL BE INSTALLED TO SPAN 16', ONE END SUPPORTED BESIDE AN EXISTING POST, AND THE OTHER ON A NEWLY ADDED POSTS 16' AWAY SUPPORTING THE EXISTING BEAM AND THE NEW ONE WHICH WILL BE SISTERED ALONG SIDE IT.

WHAT SIZE BEAM DO I HAVE TO "SISTER" ALONG SIDE THE EXISTING ONE IN ORDER TO REMOVE THE CENTER POST?
Tushar
10 Mar 2011, 10:17
would you please tell me when fireproof paint to be used

1. before the beam column erection

or
2. After the beam column erection

looks forward to get your answer

Thanks

Tushar

Engineer
Stephen
10 Mar 2011, 12:43
Tushar, the inspector only added the requirement after construction was completed, so it was applied after steel was in place.
elmo rojas
01 Jun 2011, 07:41
like to see carson answer

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