I am looking for opinions on this engineers suggestion for a beam
I live in a two-story house built in 1964. We are remodeling the downstairs, including removing a load-bearing wall. In stead of trying to wing it myself, I hired an engineer to determine how to support the loads on a beam instead instead of the wall. He gave me three options, and I am a little confused about the third. The span is 15″ with uniform loads. The beam will be flush with the ceiling, so it must not be taller than 11 1/4″. The joist will be attached on the sides of the beam with hangers. The joists to the north are 16′ long. The joists to the south are 12′ long.
The engineer determined the loads to be 1303 pounds per linear foot on the beam.
The first option is (4) 1 3/4″ x 11 1/4″ LVL. This meets local building code according to him, but he says it will deflect more than he would like to see.
The second option is the same as option #1, but also adding a second beam 5.5′ to the north composed of (3) 1 3/4″ x 11 1/4″ LVL. This will create a LOT more work and cause me to tear into the living room ceiling and walls that are all plaster. I DO NOT want to do this.
The third option is to use a beam that combines rectangular steel tubing with (2) 4″ x 12″ beams bolted to each side.
Does this make any sense? Wouldn’t an “I” beam be a better option over a rectangular tube? This beam is going to be 11″ wide. A W10x15 steel beam would be almost the exact same width and thickness top and bottom as this tube. Both are 10″ tall, 4″ wide and have .25″ wall thickness.
This may be the result of my input. I asked if a flitch beam type arrangement would improve the results of the first option. I thought a piece of steel sandwiched between the LVLs might do the trick. This may be a great option, I don’t know. I just wanted to get another opinion. I attached the data for the single beam option #1 and the proposed changes to the floor plan. Also the wood / steel beam drawing.
Replies
So what I’m seeing on this lvl span chart is three 11.25” lvl’s for a 14’ span. 16’ doesn’t show 11.25 as an option. But you are at 15’ so 14’ is close. He’s got you going with a 4 ply lvl so that’s probably fine for the 1’ discrepancy. This is with 40 lbs live load and 20 dead load per sqft. If 4 ply meets code but deflection is such a concern make it 5 ply but it’s probably overkill. I’d skip the metal.
https://www.fp-supply.com/cmss_files/imagelibrary/Microllam/Microllam%20Technical%20Page.pdf
I think 5 LVLs would definitely do the trick. The local price I am being given is $9.99 per linear foot on the LVLs. So I would need 16 ft. per LVL times 5 for a total of 80 linear feet. At this price, the wood is going to cost over $800. Compared to the steel I- beam, which is is $360. I think the steel might end up being the cheaper option. The rectangular tubing is more expensive at just over $500.
While I can provide some general insights, it's crucial to consult with your engineer to ensure the structural integrity and safety of your remodel. That being said:
1. **Option 1 (4 LVLs):**
- Meets code but has higher deflection.
- Consider additional support or reinforcement.
2. **Option 2 (Additional beam to the north):**
- Complicates the project and involves tearing into ceilings and walls.
3. **Option 3 (Steel tubing with 4"x12" beams):**
- The choice between a rectangular steel tube and an I-beam depends on the specific loads and structural requirements.
- An I-beam (like W10x15) could be a suitable alternative and might offer better structural efficiency.
4. **Flitch Beam Type Arrangement:**
- Adding a steel plate between LVLs could enhance structural performance.
- This option warrants further discussion with the engineer to assess its effectiveness.
Given the complexity of your situation, it's advisable to have a detailed conversation with your engineer. Discuss the pros and cons of each option, potential long-term impacts, and if there are alternative solutions. If you have concerns or preferences, communicate them to the engineer to arrive at the most suitable and safe choice for your project.
Don't use span charts to size the final beam. It doesn't take shear or bearing into account, or unusual loading. Signed, a structural engineer.
CJ Cake, what's unclear to me in the information you provided is how the composite steel/wood beam was designed. Is it simply a steel beam padded with wood for attaching joist hangers? Or is this a true composite beam that relies on the wood component for additional strength and stiffness? Either way, I wouldn't suggest modifying the engineer's design on your own if you can't perform the necessary design calculations. That being said, I agree with you that an I-beam is likely a better solution in this case than a rectangular steel tube.
If I were in your position I would ask the engineer to size the appropriate I-beam to carry the load on it's own. It could be a W10x15 as you've suggested, but it might be a W10x17, W10-19, or something else. Once you have the appropriately sized I-beam it can then be padded out with wood on each side (or the top) to attach the joist hangers.
Also, see the relevant fhb articles below.
https://www.finehomebuilding.com/project-guides/framing/steel-with-wood-framing
https://www.finehomebuilding.com/project-guides/framing/when-wood-falls-short-steel-i-beams-do-the-trick
I spoke with the engineer. His thoughts on this choice were to use the rectangular section with two LVLs, one on each side, as a composite beam. The rectangular tube is 4" x 10" and the LVLs are 11 1/4" by 1 3/4". The beam's total width would be 7 1/2" with wood on each side for the joists, and it could be supported by a 4 x 6 and 2 x 4 stud fastened together on either end, all flush with the walls and the ceiling. But he didn't explain why the I beam would be able to do the same thing?
CJ,
I think the best course of action here is to finish working through the problem solution with the engineer. Be prepared to pay for a few more hours of his time but also make it clear to him exactly what you don't like about the existing designs and what you would like changed. If he tells you something won't work or isn't a good idea, ask for an explanation as to why. And keep asking questions until he explains himself clearly.
For a competent structural engineer this is a straight forward problem, but one that can be solved in many different ways. Because of that it's up to you as the owner/builder to define what types of design solutions are acceptable.
Just my 2¢.
just slightly reduce your span by having some wall continue into that space. make it a built in bookcase or something....
We considered this, but it is not going to work for this space. Just 2 feet would have solved all my problems.
then i think a steel i beam is the most prudent
Perhaps. But then one has to consider all that will be involved to get it installed. It is not as simple as saying a steel beam would be better than wood. Think through each required step to get the beam into place.
can you put a steel bar, say 1/2 by 10 between the 4 lvl’s to help with the deflection?
I could not resist examining this one.
My thoughts:
Use (3) 1.75x11.25 LVLs. Sandwich a 3/8" x 11" steel plate between the LVLs (total of 2 plates). Through bolt at 12" /c/, T&B, 2" from edge.
Challenges:
- How to get the ends in place on top of an adequate bearing wall. The beam will be longer than the clear distance between walls.
- Can you easily beef-up the walls to carry the load from the beam?
- What is below the beef-up walls (e.g. lally columns in basement)?
- Can that load be carried safely down to solid ground (ftg)?
- Accurately doing the drilling thru 5 members so that the bolts are snug in all (5) members.
- Total beam weight will be about 280-300 lbs when assembled.
- WHEN do you assemble it - in-place (one piece at a time) or on the floor?
- Can your plaster ceilings tolerate the additional 0.4" at mid-span of this beam once it carries all that is asked of it?
- Screw all joist hangers (no nails).
JMNTBO. THIS IS NOT INTENDED TO BE A FINAL DESIGN!
[email protected]
I will try to answer these questions for you.
Q1. Can you easily beef-up the walls to carry the load from the beam?
A1. The east, exterior wall is already exposed and the space can have additional studs added. Five 2x4s in a stud pack or a 4x6 with a 2x4 added to one side. The other end is a challenge because it will need to rest on a wall that is surrounding the stairwell. I may have to add a small section to the wall for adequate support. See the attached drawing.
Q2. What is below the beef-up walls?
A2. There is a 20" crawl space. The subfloor is 2x6 tongue and groove pine supported every 48" on 4x6 girders. I was able to dig and pour a 2' x '2 x 2' footing with a precast pier on both ends.
Q3. Can that load be carried safely down to solid ground?
A3. I think this is already figured out at this point.
Q4. Accurately doing the drilling thru 5 members so that the bolts are snug in all (5) members.
A4. I am able to do this with a little patience. I can drill the pattern into the first steel plate, then use a transfer punch or similar to layout the rest of the pieces. I have a drill press that will clamp to the pieces to keep each hole aligned and square.
Q5. Total beam weight will be about 280-300 lbs when assembled.
A5. I would probably rent a beam lift and assemble it on the ground and lift it as a single unit.
Q6. Can your plaster ceilings tolerate the additional 0.4" at mid-span of this beam once it carries all that is asked of it?
A6. I have no idea. the area on either side of the beam (24") will be stripped and repaired with drywall. I hope to blend this into the plaster, but I am not experienced doing this type of work.
Q7. Screw all joist hangers (no nails).
A7. Absolutely! This has already been approved by the engineer in accordance with Simpson recommendations.
I just completed a design for a very similar application.
I will post sketches in a bit.
BTW, if there's not at least 6" of new concrete under what appears to be a precast deck block/footing, I wouldn't be comfortable dumping the almost 10K lbs onto it.
That footing is about 13 inches thick. I was shooting for 12" but I mixed a little too much concrete and the precast block is imbedded about 2".
"A5. I would probably rent a beam lift and assemble it on the ground and lift it as a single unit."
That's fine, but you're not going to put this beam on a lift with it being level - see my sketches.
Consider:
- You are likely going to have to cut every joist on each side of the existing bearing wall to provide a "slot" for this new beam.
- You will need to construct a temporary wall on each side of the where the new beam is going to support the joists and the floor above. This impacts the room that you have to raise this beam into place.
- It would be easier to "drop" this new beam into place from above, but that's typically out of the question because of existing 2nd floor partitions.
No matter how you tackle this, it's not an easy task. The toughest thing I see is getting this beam into its proper location (i.e. sliding it equally onto both supports) while its top surface is in full contact with the subfloor above.
While I am not saying your engineer is wrong, I'm a bit confused on how he got that load per linear foot for your beam. Some napkin math on my end from your numbers comes up with 840 pounds per linear feet for that floor load, assuming 40 live 20 dead. did anyone else get something sim?
pretty simply= (16*60/2)+(12*60/2)=840.....
or is there also a roof load bearing on this?
Consider the possibility that there is an accessible attic above the 2nd floor.
OR, the ridge is supported by a bearing wall in the attic.
From here, we can't see the multiple load paths from roof + attic(?) + 2nd floor -> beam.
The 1303#/ft can be derived if one considers an approximate 30 psf load on the attic floor (I get 33 psf total from attic).
It doesn't matter whether it's a square steel tube packed out with LVL's or a steel I -beam packed out with LVL's. In my experience we always use either a glitch plate or I-beam and order it with all the holes for the bolted connections obviously. Temp shore up the joists on either side and cut out a slot and slide the beam on up. Little problem with your engineers preformed concrete block on top of the footing pad. Number one, the footing pad is likely undersized by modern standards but will do the trick either way in reality. Number two, that pier is smaller than 12x12" that is typically too small unless that blocks spec is different from the blocks at home depot. If so, then nevermind maybe engineer thought that through. Not much too this, figure out the load which is a piece of cake, and spec the beam. Install it, done.
Nice over-simplification of the challenge.
Sure, size some beam options, pick one, and install it.
The REAL challenge involves getting the chosen beam properly into place.
It is, but it's the only way to get to working on it. Engineer figured out the calcs, just need to slide it up in there with some Jack's and a guide after temp sharing and cutting out d beam. Nothing to it :)
Ahh, reno work. Simple, no surprises right?
How many electrical runs will have to penetrate the beam? Plumbing?
Gotta plan ahead cuz if you're using steel+LVL all penetrations are best accounted for before putting the beam in place.
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Wonder which direction @CJCake is leaning...
Tis a good point. If your order the steel beam without even cutting into the drywall to see the whole picture, you will be in a pickle down the road most certainly in one way or another. I would hope the engineer would have requested photos of exploration before making a call and slamming the stamp but you never know these days with engineers of the newer generations. V.I.F. is a poor substitute for doing the work the first time around. Had an engineer last week spec out replacing a hang cut beam stock rafter roof and on site built porch truss replacement of certain components like the bottom chord and diagonals but leaving the top chord and raftera... on a sinking roof.. thought we could just jack everything up and temp up rafters with not BM support or ridge and straighten out car decking that had deformed for 20 years. Keep an eye out for the people that work for you, you will find yourself babysitting the engineers, designers, and everyone else in the industry as the performer of the work. Scornful Outlook, maybe, reality, definitely ?
While I can provide some general insights, it's crucial to consult with your engineer to ensure the structural integrity and safety of your remodel. That being said:
1. **Option 1 (4 LVLs):**
- Meets code but has higher deflection.
- Consider additional support or reinforcement.
2. **Option 2 (Additional beam to the north):**
- Complicates the project and involves tearing into ceilings and walls.
3. **Option 3 (Steel tubing with 4"x12" beams):**
- The choice between a rectangular steel tube and an I-beam depends on the specific loads and structural requirements.
- An I-beam (like W10x15) could be a suitable alternative and might offer better structural efficiency.
4. **Flitch Beam Type Arrangement:**
- Adding a steel plate between LVLs could enhance structural performance.
- This option warrants further discussion with the engineer to assess its effectiveness.
Given the complexity of your situation, it's advisable to have a detailed conversation with your engineer. Discuss the pros and cons of each option, potential long-term impacts, and if there are alternative solutions. If you have concerns or preferences, communicate them to the engineer to arrive at the most suitable and safe choice for your project.
nore detail is provided in pdf attached
@andy91: Insightful view of the design profession. I try NOT to fall into that category, as evidenced by my comments on this topic.
Architects are generally worse than engineers when it comes to the "How to" of construction. Home designers are another category (even worse). The younger generation of engineers suffer from a lack of mentoring with regard to thinking things thru to the final outcome.
And then there's the "Sticker Shock" of engaging a competent engineer. Most homeowners cringe when informed what the fees will be and then shop price. While they may find an engineer who'll design the beam for the span and nothing else. It then becomes the contractor's problem who must figure out how to put it all together.
I still am wondering what OP (@CJCake) plans to do.
I haven't been around Ling enough to see your contributions to the community. Recently took to the forums for lack care I've noticed for ones craft in my market. Even the decent ones don't have passion for what they do (speaking of 95% of subs round here). I sympathize with the designer engineer comment not knowing the know how. Here neither the architect or the engineer know what they're doing really. Ours haven't ever framed a house much less remodeled a bathroom. Result is as you'd expect, hilarious babysitting fest. I'm 32 years old and this new industry makes me feel like a grandpa. Cheers to the old guys that used to build ?
Some of us are so old we follow the model of forgetting half of what we learned.
True perhaps. But today's "pros" know less that what older guys still remember. While I was often considered the 'office guy', once my field guys got to know that I got my hands dirty often, we got along great. I learned early on that just 'cuz you could draw it on paper doesn't necessarily mean it can easily (or at lower cost) be built. Spending much time in the field allowed me to "mine" the minds of many trades for the pitfalls and solutions they've encountered. Several major projects' "how to' challenges came together over liquid libations after hours (70s & 80s). As a practical and pragmatic engineer my career path was (kinda still is) scary, embarrassing, insightful, learning, fun, etc. When it comes to construction challenges I'm always working toward the right solution and not necessarily the fastest.
How long have you been around this forum?
That is too funny. I forget things as well, especially terminology lingo not often used or irregular roof cutting offset math those specific things. glad I'm not the only one lol
You've been given a few options for replacing the load-bearing wall with a beam, and you're seeking clarification on the third option, which involves combining rectangular steel tubing with wooden beams.
Regarding your question about whether an "I" beam would be a better option over a rectangular tube, it's essential to consider several factors:
Strength and Load-bearing Capacity: Both "I" beams and rectangular steel tubing can be engineered to support heavy loads. The choice between them depends on the specific structural requirements of your project, including the span, load distribution, and any other factors that might affect the beam's performance.
Flexibility and Versatility: "I" beams are commonly used in construction and offer excellent strength-to-weight ratio, making them suitable for a wide range of applications. Rectangular steel tubing, on the other hand, may provide more flexibility in terms of design and installation, especially when combined with wooden beams.
Cost and Availability: The cost of materials and labor for fabrication and installation should be considered. Additionally, availability of materials and local building codes may influence your decision.
Aesthetics and Design Preferences: Depending on your aesthetic preferences and the design of your space, you may have a preference for one type of beam over another.
Considering the similarities in dimensions between the proposed combined beam and the W10x15 steel beam, it's crucial to assess the structural integrity, load-bearing capacity, and potential deflection of each option carefully. The use of a flitch beam, which involves sandwiching a steel plate between wooden beams, can indeed enhance the load-bearing capacity and reduce deflection, but it's essential to ensure that it meets all relevant building codes and standards.
Ultimately, I would recommend consulting further with your engineer to discuss the advantages and disadvantages of each option in detail, including the feasibility, cost-effectiveness, and structural performance. They can provide you with the expertise and guidance needed to make an informed decision that best suits your project requirements. Additionally, if you have concerns or questions about the proposed solutions, don't hesitate to seek clarification from your engineer or consider getting a second opinion from another qualified professional in structural engineering.
No real person could correctly spell that many words in a reply.
Sounds like an AI bot to me.
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I've been around FHB for a few decades. Been visiting the online forum for maybe 10 years. Don't know for sure 'cuz it's not something I keep track of.
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Been involved in the construction industry since 1969.
Definitely an AI spell check at the least ?