The Right Beam Size

How can you possibly believe you have given enough information for anyone to intelligently answer your question? At the very least, you need to supply loading characteristics and allowable deflection. Even then an engineering answer does not necessairly satisfy building codes.

Hello dimcd,

I assume you needed this span to allow a large open area in a hall or something?

What are your measurements in. Inches or cm? Are you talking of a 8" by 33" rsj, or 'I' beam? And is there fresh air above? Sorry to be so obtuse but the detail is sadly lacking in your question.

Is it carrying a flat roof or conventional tiled roof?. Is there another storey above the one you are putting the beam in?

Please get back with more details. Including what your single storey modular is?

I assume that by single story modular you mean a single story modular home. In order to answer this question, you would have to look at your local building code (probably the international building code as adopted by your state), and information from the modular manufacturer.

The modular manufacturer will give you load information. I have designed framing for modular and mobile homes many times, and often the load changes along the length of the building due to concentrated loads from openings within the marriage wall, etc. This would mean that you would have several possible load configurations, and potentially several beam sizes required.

It is also important to know where these loads act on the beam. The manufacturer will have a layout showing where the beams should be located, and how any intermediate beams should be installed. Is the load distributed over the length of the beam or are there point or concentrated loads along the length of the beam.

The manufacturer will also give deflection requirements, or if not the building code will provide that to you.

And finally, what grade of steel will you be using? This is a very important part of the design, how strong is the material you wish to use?

This should be done carefully, and if you are not sure of the right way to go, retain a structural engineer, the cost is worth the piece of mind!

Hope this helps - YE

While I appreciate the other messages needing more information. To tell you what size is needed we would have to have that. To answer your question " is an eight inch beam large enough to span twenty two feet?" the answer is no. in any situation. Good Luck.

The beam would deflect under it's own weight, much less the loading from the modular!

22 feet? The answer is not no, it is Heck No!!!

Hello Dlingo,

can anyone confirm a W8x33 beam is right?

As you can see the beam mentioned is 8" wide and 33" deep. It is not April already is it? Seems like a jest really. That is if the measurements are inches? They could be in cms? If it is inches it is almost a metre deep. That is a fare sized girder. But he was nowhere near specific enough. And it looks like he has done a runner as well.

W8x33 DOES NOT MEAN 8" WIDE AND 33" DEEP THE 8 MEANS THE NOMINAL HIEGHT IS 8" THE 33 IS THE WEIGHT IN LBS. PER FOOT

Hello erector1:

I thank you for pointing my error out and explaining it, sincerely.

When I was spanning 9ft, ~3m, I used bigger steels than that!. I would imagine you would see and maybe feel the flex in this at 22ft and I presume another 18" for the pad either end? When I say flex I mean before there is any load.

Thanks again! Learning all the time! When I was looking for I beams I automatically think of the brick pillar as 9" x 9", 225mm x 225mm, to allow the beam width to fit inside the wall. It did seem rather OTT high at almost a metre!

Take care, and have a wonderful new year........................

I am awaiting loading information from the manufacturer and will return when I have it

Thanks

I calculate less than a tenth of an inch deflection under it's own weight. 8x33 is a pretty stout albeit shallow beam. It is possible this could work, if the loads were light enough and we could have some deflection. Let us know what you find-

YE

Dont even think about it. The floor would be a trampoline.

Questions to answer. 1) What is the space on each side of the beam to the next support or exterior wall. This beam carries half of the floor on each side. 2) What are the loads. a. Floor-Living area, b. Any walls, c. Floors above, d. walls above, e. Roof design and loads. A good rule of thum for a 22 foot span the beam would have to be at least 12" nominal height before adding any addition loads.

I have requested loading info from the manufacturer but have heard nothing.

When I receive more info I'll post, 'til then , I thank everyone for their imput.

djmcd

Hello Guest,

I am glad you are still looking at the posts on your thread. Thanks. I would like to say I mean no offence! But you just sent in info we already have. Can you not give more detail on whether there is another floor, or a tiled or slated roof?

I may be stating the obvious, but, 'near enough' is not good enough when you are building a house. ........................The beam will not break! But if it continues to be 'springy' the force will work it off the pillars, and or bring down whatever is above.

I can only wish you luck. I have never in my life had a manufacturer give me the strength of a beam. They can perhaps give you a list, or more likely the people you bough the steel from will tell you its strength over a given span. I have never seen such a list. Not for a 'one off' steel. If you were talking of steels for a whole row of houses then you would need to know and the people delivering the steel will give you the figures, or the Archtect will know the strengths before he even designed the place and building started. But, for a steel bought on 'spec', no.

Good luck anyway.......................

Hello sales@marlynsteel.com:

Do you not want to scream sometimes when you see replies like, "I am awaiting loading information from the manufacturer"...........?

As far as I can see he has not mentioned if, as you say, the next floor will have bedrooms, bathrooms, if there is another floor to go on the next? Nothing.

We used 12" or 15" high by 9" or !0" deep. That was spanning a max' 8' or so. He has somehow got the idea a smaller beam will work for a span 2.5 times the length.

If the OP already has the beam, just put each end on a couple bricks and stand on it?

Not enough info' and not listening. Why does the OP not want to get a larger/stronger steel? I cannot answer that........... Why ask then take no notice. I hope your email you have as your name will add weight to the remarks from you and, perhaps the OP may come round to see that the steel he/they are speaking of is not strong enough?

Take care.......................

The correct thing to do is. 1) roll your drawings to your pretty new house up. 2) Stick them under your arm. 3) Go to a steel fabricator with an in house Engineer. He will tell you exactly what you need. Sell you one and even deliver it to your yard.

Good Luck

Hello sales@marlynsteel.com:

Well said sir!

Take care.................