Wood beam to steel for ceiling support - hard to size

[Don Alexander]

any attempt to do what you are talking about without consulting a structural engineer is pure folly

better safe than sorry

+1 on the investigating cost comparision of remodel vs. building new

you might very pleasantly surprised

[Mitchell Andrus]

Matt, we're gonna talk you into putting up a new building if it's the last thing we do. $27-33K plus a little more for a nice facade..... You were going to spend half that just to get a half refurbished, out of plumb barn.

C'mon.... Man-up. You know you want it.
.

[Matt Neil]

You guys do make me laugh. Every contractor that came out to look at the project told me that a new building would be cheaper. And everytime I agreed. But if you've seen the aesthetics of these historic barns, you know they can be intoxicating. The costs to lift one of these beasts, move it 50', excavate the old foundation and floor, place a new foundation that reaches the frost line, move the barn back and pouring a floor will surpass a new building alone. Then there's siding that needs replacing, electrical, insulation...will I be able to move tools in then? It's a long process but I'm still young. I'll take it slow and pay as I go.

A lot of you have suggested I talk to an engineer. Good thing I did (as I posted earlier). But great ideas coming from this. Neither I nor the engineer talked about the side plate idea. I'm going to email him that tomorrow. I'm still open to ball park educated guesstimates on this. One thing I don't want to do is overbuild these beams. I know the haymow holds well over 100,000 pounds, and I don't need it to support that much when I'm done.

[Lee Koepke]

You guys do make me laugh. Every contractor that came out to look at the project told me that a new building would be cheaper. And everytime I agreed. But if you've seen the aesthetics of these historic barns, you know they can be intoxicating. The costs to lift one of these beasts, move it 50', excavate the old foundation and floor, place a new foundation that reaches the frost line, move the barn back and pouring a floor will surpass a new building alone. Then there's siding that needs replacing, electrical, insulation...will I be able to move tools in then? It's a long process but I'm still young. I'll take it slow and pay as I go.

A lot of you have suggested I talk to an engineer. Good thing I did (as I posted earlier). But great ideas coming from this. Neither I nor the engineer talked about the side plate idea. I'm going to email him that tomorrow. I'm still open to ball park educated guesstimates on this. One thing I don't want to do is overbuild these beams. I know the haymow holds well over 100,000 pounds, and I don't need it to support that much when I'm done.

I am a contractor ... I probably would tell you the same thing ... followed by "it can be done" .. personally I could cringe at the thought of tearing something like that down and putting up a new 'modern' conventional structure. I, personally, would take the time to understand what you need and figure out a way to do that. Make sure you let us know how it turns out.

[Chris Parks]

Everyone gets carried away with the size of beam needed to span 50 feet. Supporting a beam in the middle has cut it down to 25 feet with appropriate footings, that's easy. Now put a lighter than usual beam in which is easier to handle and add strength to it in position. What I did with engineered approval was put a lighter beam in and then bolt a post onto the beam in the middle which dropped about 1 foot. I then fabricated a long rod bolted to the ends of the beam and which ran under the centre post. This rod was threaded on the ends and the rod was tensioned with nuts to support the middle of the beam, we in fact initially tensioned it too much and pulled the beam upwards and had too loosen it off. The big "if" here is to have footings each end to support the extra load. Engineers don't need to know the load going onto the beam, they have standards that allow for this. I was told that the greatest load is a crowd of people on a floor and not machines etc which we all regard as very heavy. Others may be able to correct me if this is wrong. I in fact suggested this method to the engineer and he was very agreeable and drew up the specs with no hesitation at all. It has not fallen down since I did it so I guess the idea works.

[Dan Hintz]

If you don't mind the money, nothing stopping you from creating a new building that has all of the charm of the old barn style...

[Don Alexander]

I was told that the greatest load is a crowd of people on a floor and not machines etc which we all regard as very heavy.

no doubt about it , live load is always greater than static load on the same or comparable weight ..........has to do with movement and vibration for starters

as for fixing the old , nothing wrong with that old barns have a certain appeal

[Nick Laeder]

Depends on the use of the structure. Live load on a library floor will never come close to the dead load, even when factored for uncertainty.

I have a degree in structural engineering, but don't practice. What you're talking about is certainly possible. I'd consult a practicing Professional engineer to come to the site and look at it. Your buddy the engineer can probably figure it out, but a firm that provides design services for new-built commercial structures may not be able to assess the existing conditions properly. Thankfully you're doing new foundations, that removes possibly the biggest unknown.

If you were on the Front Range, I know a company that would love to help you.

[Henry Ambrose]

Don't give - up you can do this and it'll be great when you're done.

[Matt Ellis]

I'm a structural engineer by profession, and we regularly see this sort of thing. I've read the thread, and I think what you're proposing is a possibility, but there are a couple of things that need to be addressed.

If I understand your problem correctly, you have a second story/mezzanine that is supported by your joists. You want to retain some of the live load capacity of that second floor, but you don't necessarily need the original design capacity.

If I were evaluating this structure, I would get an estimate of the dead load weight of the structure (probably about 15 psf) as well as the desired live load capacity. I'd probably assign a live load capacity for the 2nd floor of about 40 psf...maybe 50 if you're going to have lots of stuff up there. You said that existing floor supported 100,000 lbs at one point. If that is true, and the load was evenly distributed over the footprint of the barn (1500 square feet) that corresponds to a live load of about 67 psf.

One other thing to consider, which has not been mentioned yet, is the roof framing. Are there any interior supports? Do you have posts that support roof framing, and fall on the beam lines that you want to modify? If so, you need to take that into account when sizing the new steel. Code required roof live load is 20 psf, but snow loads may control wherever it is you're located.

I'd also suggest bolting channels to the sides of the beams in lieu of the steel plates. Rolled channel sections are more efficient than flat plates, which means you'll end up with lighter sections. Lighter sections equal less material, less labor to install and less money for you.

Beyond strength considerations, you need to consider deflections and serviceability requirements. I can't give you any specific recommendations without access to the entire situation, but generally a 6"x4" tube section will NOT be acceptable on a 25' span. Deflection is a function of the loads applied and the area that the beam supports, but a 6" beam spanning 25' with the load magnitudes you're talking about will be like a limp piece of spaghetti. Walking across the 2nd floor would be very similar to walking across your kids trampoline.

You're probably looking at a 12" channel minimum (bolted to each side of the existing wood beam) to be able to span the distances you're talking about.



-matt

[Don Jarvie]

Have you looked into engineered wood I beams? My BIL has been building a few houses with them to eliminate the row of posts in the basement.

I have to lean towards a new building. You can take the best outside features of the barn and replicate them but having a new interior like high ceilings, customized second story storage features, etc may be worth building new.

[Matt Neil]

I can put up a new building for the same money I'm putting into this one. But it won't be the same building. Sure I could have a brand new pole building for the shop I'm envisioning. Instead I'll end up with a 25'x30' shop that uses only 1/2 of the first floor. That will give me room to expand should I choose to. Plus I have a second floor that's 30'x50' with no walls or supports. Just open space. The ceiling is supported by the exterior walls. The second floor has an easy 20' ceiling height. And none of that includes the 14'x50' lean-to on the side.

W8x31 king beams will be used for support. The barn was moved Friday and most of the concrete was tore up yesterday along with a hole to bury it. The excavator should be done Monday and footings will be poured this week.

I'll be getting quotes on new siding in the next week or two but will probably delay that until next year. I'm leaning towards either tin (cheap) or fiber cement 4x8 sheets (more pretty).

[Matt Ellis]

Nice looking old building. If you have the funds for the renovation I can definitely understand the appeal.

Am I reading that you're planning to used a W8x31 for the 25' beams you were trying to size earlier? If so, and you have the headroom, I'd suggest using a W14x30. Should cost the same (steel sold by the ton) but have MUCH better strong bending/deflection performance.

-matt

[Matt Neil]

The headroom is the kicker. I'll have about 9 1/2' to the joists. Then the two beams below that.

[Jim Becker]

Wow...what a classic building! If you have the resources available, that's a very nice structure to save, update and enjoy. Bravo.