What Size Support Beam Will I Need?

I'm not a civil engineer. If I were, I'd tell you that there is no way to answer your question without much more information, and a site inspection by an engineer.

You don't want your roof to collapse, do you?

I agree with lynlynch. Steel beams are costly, and if this is a house, I've never seen them used for this in residential dwellings.

You could probably use a glulam beam............way cheaper, not to mention, less weight.

When it comes to load bearing walls, a quick look by an engineer is a good idea.......or possibly even a reputable licensed contractor in your area.

Hate to be critic, but I am afraid you are incorrect. Even within the past two weeks I persoanlly have been involved in structural calculations for residential conversions where steel UB have been used to provide internal support where alternative methods are not only impractically, but more expensive! Indeed the structural beams have been used to support complete floors, partitions, loft conversions, even walls in numerous conversions to existing properties with the United Kingdom.

In regard to LynLynch's reply, yes a structural engineer would require more information, it is straight-forward finding out what type of beam is required for the forum contributors needs as long as appropriate information regarding the surrounding building structure and support requirements are provided (usually acquired during a site survey). In the UK building regulations stipulate that the structural calculations be proven and supplied to local building control accordingly; otherwise planning permission will not be granted. In the US, I am not sure what the exact regulations are, however, a large proportion of houses are "timber frame" construction unlike the UK, where brick/block is the predominant construction method, thus steel in the former case would seem extreme, whereas in the later, on the contrary a more via and cost-effective solution.

I don't mind criticism, I was throwing out what I knew based on my limited knowledge of the subject. Criticism is important on here, I've seen people post some really bad/dangerous answers, while at the same time acting like a professional in whatever is being discussed. Not good.

In the US, anything, remodels, etc. regarding load bearing walls is required to be permitted. He's probably trying to avoid that hassle. I don't blame him, I avoid those when I can too.

If it was me, I'd get a good contractor have a look and draw me up a sketch of how it should be, this could be as little as $100. Then I'd jump on google and start doing some research to insure that this design is the best and most cost effective.

G,day from Australia. I would assume that like Australia your country would have a light timber framing code, that would have details of the sizes needed, typical applied load, and spans for different types of material. What you are planning is what we call a hanging beam, usually at right angles to the ceiling joists, however I have seen the beam run the same way as the joists with a light grade hanger running across the top of the joists. Whatever material you use for the beam dont forget to allow for deflection in the middle of the span (sag) especially if you use guess work instead of an engineers specs. Sometimes the suppliers , especially of steel will provide span tables for you.hope you win,A few dollars spent now might save you a lot of heart ache down the road

Col

TRADA tables are the best

Check with your local building inspector. I seem to remember reading something about not allowing the use of steel beams in residence due to loss of structural integrity in a fire.

First of all I am a little bit puzzled by your description of the wall as being "semi-load bearing"...either the wall IS load bearing or it is not...there is no in-between.

As for the size of the beam, you need to know the loading condition for the beam (is it supporting a floor above, just the ceiling, the roof or a combination of the above). Once this information is known then you can determine the load that the beam will need to support and properly size it. As Kramarat suggested you might want to consider a laminated wooden beam instead of steel unless the depth of the beam will be an issue. There are some very good "Gluelams" on the market and the cost is not too great.

Tom Consulting made an interesting comment regarding the use of steel beams but if you have a fire hot enough to cause a steel beam to loose strength then it will burn a wooden beam so I don't believe that will be a real concern.

What about the footing for your new beam? Remember that you will now be putting all of the load that was on the entire wall into two spots on the floor so you need to make sure that the floor will support this new load and also make sure that your support columns (typically several 2x4's nailed together) is properly sized to carry the load.

Guest from down under also made a good point regarding deflection of the beam. You need to take this into account and do something to "pre-camber" the beam or you may have problems with cracking sheetrock or walls above. I replaced a load bearing wall with Gluelams and put a tapered shim on the top of the beam to address the deflection issue and had very good success with it.

Good luck with your project and I would suggest that you get a local engineer or contractor to review the loading condition and deflection for the beam before you make any move.

In OZ we cannot put in a steel beam without an engineers specification, however we can put in a glulam or LVL beam using span tables to determine the size required. Accordingly the timber suppliers can provide span tables for timber, glulam or LVL whereas steel suppliers are forbidden to provide span tables to the general public or even to builders.

You must also realise that steel beams deflect ( bounce ) and therefore you need to go to a larger size to reduce this. By larger i mean a greater distance between the stringers i.e. a 3/16 x 2 x10 will be better than a 1/4 x 4 x 6 for the same weight. I hope you are seeing the need for an engineers input! Timber doesn't bounce as much and so is used more often for that reason alone.

you need to do some deflection analysis to substatiate that claim that timber will deflect less than steel, the modulus of elasticity for mild steel and spruce are vastly different, and are not differential in the same ratio in respect to weights of material. One of the best performing strength to weight woods strangely enough is Balsa (hence the reason why the de Havilland Mosquito was built from it - and not simply because of the shortage of strategic materials at that time, but when used in ply form, it is extremely strong and easy to repair in the field).

As stated earlier Trada tables for timber beams, joists, rafters, etc.. are useful, and can be purchased from good bookshops; in regard to steel section performance there are some good sources of information available; but by the time you have bought all that you may well have procured the services of a qualified engineer.

You can buy a factory made beam, rated for any given load and span.They are made from laminated OSB material,and are much lighter and cheaper than your proposed method.Tell your local building supplier your application,and the company that makes them will tell you what you need.

A lot depends on roof pitch, snow load, and wind load in your area, whether there is a second floor above, etc.Give all the details to your material supplier.

HTRN

pulpmillguy has many good points. No such thing as a semi load bearing wall. When doing such work you should really consult your local building inspector. This is major structural work and the building inspector is your best bet for the right answer. In the end it will probably be cheeper to have an inspector or engineer come in and tell you what you can do. If you don't do this project right the first time it may cause more expensive damage to your house further down the line.

If you plan on going it alone there are many places that can help size up the beam. You Building code would be the best bet, it should have tables that help detetmine beam size. Local lumber stores sometimes have tables that will help you size up the beam. If you plan on doing a bunch of work to to allow you to fasten other beams to it an LVL would be the best bet, not a steel beam. A company that sells LVLs would also be able to help in sizing the beam, they will build for your needs.

I'm in agreement with lyn, obtain the services of a Licensed Structural Engineer to observe the existing conditions, perform the necessary calculations to determine the most suitable and cost effective construction solution, and prepare a Construction Document to submit to the local Building Inspector/Code Enforcement Officer.

Over the years I've seen too many (many dozens) structural failures resulting from DIY construction by both Owners and their Contractor that didn't know what they were doing and did not rely on adequate structural evaluations and computations nor consult with a PE......in at least two of those failures the end result was several fatalities of the occupants, and another 3 where the Contractor's crews died. Not a pretty sight and highly dangerous situations.

I suspect that if you are in the US, you are going to need a a set of plans showing the beam, designed, signed and stamped by a Civil engineer licensed to practice in your State as part of your building permit requirements. Unless it is a agricultural pole barn type building you will need a building permit. (Or alternately you caould have the building department red tag the buidling and shut down occupancy until an approved repair is instituted.) Hire a Strcutural or Civil Engineer licensed in your State.