Structural Engineer anyone?

K2Kraze

K2Kraze

AzB Silver Member
Silver Member
Anyone available in the forum that can answer a 2nd floor table installation question or two from a Structural Engineer viewpoint? We are building a custom home working directly with the architect and builder, and would greatly appreciate some insight as to what we need to be looking for on our framing plans, etc to make sure it is done properly with no surprises later. Or is everyone going to recommend getting my own local SE in the Fort Worth, TX area to review the plans with us?

Thanks everyone!
 
K2Kraze said:
Anyone available in the forum that can answer a 2nd floor table installation question or two from a Structural Engineer viewpoint? We are building a custom home working directly with the architect and builder, and would greatly appreciate some insight as to what we need to be looking for on our framing plans, etc to make sure it is done properly with no surprises later. Or is everyone going to recommend getting my own local SE in the Fort Worth, TX area to review the plans with us?

Thanks everyone!
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Maybe tell your architect and builder that you're planning on a 2nd floor table installation.? That combination normally is pretty strong when it comes to these custom jobs and engineering requirements.



Freddie <~~~ unstructured
 
Might want to think about posting this in "Talk to a Mechanic" section...there are some great guys in that section that have done all kinds of installs and should know what precise info to pass on to the engineer (if they don't know the structural answers themselves)...
 
I should have stated the obvious I know - the architect and builder both know of course that we are planning on a 9' table for the 2nd floor gameroom. The reason I'm asking about a Structural Engineer, is that I'm looking for the "trust but verify" plan :smile: We have been reassured that the floor will indeed be able to handle the table weight, etc, but what I'm after is a little more detailed information so we know what to specifically look for in the framing plans and what intelligent questions to ask before the plans are final. And if we really need a SE to sign off on the plans to prevent issues I have read about in this forum regarding sagging/creaky/out-of-level/etc issues. Let's do this right from the start.
 
Third year CE student.

You might as well just post your questions. There are quite a few table installers and 2nd floor table owners as well as engineers that could help you out.

-I imagine your main concern has to do with the weight of the table...you should be alright. The floor joists can easily support the pressure of a 400lbs body falling in a full bath tub.

-Assuming you have a second floor I-beam, which you should, you'll be fine anywhere you put the table. Structurally speaking, there's no difference between the main floor and the second floor, unless your house has no foundation. The second floor, like the first floor, is supported directly by the foundation.

-If your table is a one-piece slate (Diamond Pro-Am), transportation to the second floor gets hairy. A straight stair case makes things easier. Or even better, move the table before the second floor is framed. If these aren't options, you could install a large window in the table room and lift the slate with a crane. A 3-piece slate is no big deal.

-Make sure the ceiling joists are centered above the table...it would suck to get your house built and you didn't think about the table light.

-Don't forget to run the CO2 lines from the basement...what kind of man cave would it be without beer on tap.
 
Drew said:
Third year CE student.

You might as well just post your questions. There are quite a few table installers and 2nd floor table owners as well as engineers that could help you out.

-I imagine your main concern has to do with the weight of the table...you should be alright. The floor joists can easily support the pressure of a 400lbs body falling in a full bath tub.

-Assuming you have a second floor I-beam, which you should, you'll be fine anywhere you put the table. Structurally speaking, there's no difference between the main floor and the second floor, unless your house has no foundation. The second floor, like the first floor, is supported directly by the foundation.

-If your table is a one-piece slate (Diamond Pro-Am), transportation to the second floor gets hairy. A straight stair case makes things easier. Or even better, move the table before the second floor is framed. If these aren't options, you could install a large window in the table room and lift the slate with a crane. A 3-piece slate is no big deal.

-Make sure the ceiling joists are centered above the table...it would suck to get your house built and you didn't think about the table light.

-Don't forget to run the CO2 lines from the basement...what kind of man cave would it be without beer on tap.
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Leave it to a student to remember the "most important" details! :grin:
 
Drew -

The reason I was asking for Structural Engineering input was not that I don't appreciate a general forum member's input - or installer's - it's just that I have reviewed many forum posts regarding this subject and while all are relevant and well-intended, it's the detail I'm after - from someone that make their living making sure things like residential floor loading etc is done correctly and efficiently from the start.

Here are the concern areas: 1) joist spacing on standard 24" centers or 16" or what recommendation? General room size is 15' x 32' with the span length running either direction since it's not framed yet. 2) actual subfloor material/thickness/layering, etc? 3) any special reinforcement necessary under each of the four leg areas that can be planned as part of the joists/subfloor etc? 4) what other construction considerations should we be made aware of to prevent any other nuisance issues like creaks, floor noise, sagging, table out of level, etc ---- especially the one comment I see regarding how a table "settles" or the floor "settles" after a given period due to the weight and having to be re-leveled once or twice - which seems ridiculous and should be preventable if built right.

To address your good thoughts and suggestions, we have a 9' three-piece slate table that will sit over portions of other framed rooms below. And yes, the ceiling supports and electrical have been considered ---- it's that beer run from the kitchen below that we haven't yet tackled :wink: Oh, and the dumbwaiter - that's next!
 
Keep in mind, I'm no engineer. Some of these questions might be better posed on a technical forum...particularly floor sagging and sub-floor specs. FWIW, a 9' Brunswick Gold Crown 4 is around 1200lbs or 300lbs on each foot. Each foot is probably 36 square inches so you're looking at probably 8.5psi. Call it 10psi to support to the table. That's equivalent to 200lbs man hopping up and down on one foot.

K2Kraze said:
Drew -

The reason I was asking for Structural Engineering input was not that I don't appreciate a general forum member's input - or installer's - it's just that I have reviewed many forum posts regarding this subject and while all are relevant and well-intended, it's the detail I'm after - from someone that make their living making sure things like residential floor loading etc is done correctly and efficiently from the start.

Here are the concern areas: 1) joist spacing on standard 24" centers or 16" or what recommendation? General room size is 15' x 32' with the span length running either direction since it's not framed yet. 2) actual subfloor material/thickness/layering, etc? 3) any special reinforcement necessary under each of the four leg areas that can be planned as part of the joists/subfloor etc? 4) what other construction considerations should we be made aware of to prevent any other nuisance issues like creaks, floor noise, sagging, table out of level, etc ---- especially the one comment I see regarding how a table "settles" or the floor "settles" after a given period due to the weight and having to be re-leveled once or twice - which seems ridiculous and should be preventable if built right.

To address your good thoughts and suggestions, we have a 9' three-piece slate table that will sit over portions of other framed rooms below. And yes, the ceiling supports and electrical have been considered ---- it's that beer run from the kitchen below that we haven't yet tackled :wink: Oh, and the dumbwaiter - that's next!
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Sagging and settling is to be expected...this is typical of any floor regardless of whether or not there is a table sitting on it. Wood is an imperfect material. The table won't fall out of level enough to seriously affect play...but it's not a bad idea to re-level after a few months. Honestly, it's not difficult to shim the slate once it's close.

If you want the absolute in structural stability, you install the table centered on a steel I beam...the length of the table running parallel with the beam. The center of each foot will be like 18" off the edge of the beam. Install a joist under each leg. That table ain't going anywhere.

Joist spacing is unimportant if you run one under each leg. The joist is an independent system. Additionally, sub-floor material is also unimportant; the table would simply compress it into the joist.

Anyway, that's just my .02. Running a material analysis on the floor for a specific case is expensive as all hell. PE's bill out at hundreds of dollars an hour and they'll have to take your floor to the lab. That's a lot of trouble to go through for a 10psi load.
 
I'm a general contractor and run into different things like this a lot of the time. Your framing plan could allow for a second floor truss at a specified possible location(s) to double up the dead load capacity. 1200 lbs is about six or seven adults standing in a room. Not too bad.

I'd be more inclined to look at the deck material and finished floor. Particle board underlayment isn't a good choice. Laminate floors don't do well, either. You said the electical plan is noted, but as Drew stated, there might be more floor load by the wet bar. :cool:

Best,
Mike
 
Mike/Drew -

Great thoughts and input guys - thanks. Things to consider for sure and I will take them to the next build meeting for them to work with me on.

I really appreciate the time and help!

~ Kerry
 
K2Kraze said:
Anyone available in the forum that can answer a 2nd floor table installation question or two from a Structural Engineer viewpoint? We are building a custom home working directly with the architect and builder, and would greatly appreciate some insight as to what we need to be looking for on our framing plans, etc to make sure it is done properly with no surprises later. Or is everyone going to recommend getting my own local SE in the Fort Worth, TX area to review the plans with us?

Thanks everyone!
Click to expand...

My advice have a table with more than four or six legs to spread the weight, ensure steel beams under legs not wood beams under table supported by bottom cross columns. Best of luck.
 
You should be concerned about more than the weight of the table. You should be concerned about your own weight and the weight of other people in the room as well. In addition to the weight of the table, how much additional weight would it take to depress a section of the floor 5 thousandths of an inch. I think that is the correct number, anyway that is enough to cause a ball to roll off. (Bryan at Diamond told me what the number was but I may not be remembering it correctly)

I had a diamond in a second floor apartment. I was trying to level it with a 12 inch Starrett. I must have worked at leveling it for a year before I figured out it was me being in the room next to the table that was throwing it off. I would get one end perfect then work my way to the other end. Then go back and check and it was off again. Some days I would get it all perfect then have a friend over and it was off again. Some days the building would breathe during normal temperature changes and throw it all off again.

I went round and round with that thing. Two decent size guys walking around a table on a second floor will rock the table by several thousandths even time you play on it. I gave up and moved to a first floor apartment.

It will be interesting to see if you find a solution to this.
 
I design bridges for a living, does that count? Legally, I'm not an SE even though my title does say Senior Structural Engineer. :)
 
ChopStick!! Now you've done it ;-D I knew I could get something interesting out of this post - and that .005" did it alright. Seriously.

Interesting comments you made about your experiences and things I need to discuss with my builder on Monday.

I'm thinking along the lines of having two steel beams run under the legs longitudinally from each wall support from below - approx 20' span - in place of the normal I-beam joists they are planning - as well as steel cross members put in between the 20' beams connecting them under the table legs side-to-side --- create a "platform" of sorts that will act against the sort of issues you ran across from leg to leg leveling and movement. The builder has talked about using double-layered tongue and grooved 4'x8' sub-flooring vs the normal 3/4" one layer. What thoughts on this approach before I take it to the table meeting?

I'm trying to make reasonable construction requests without getting into exotic or expensive - simple engineering and well-thought out plans usually work best - I've heard ;-)

Maybe I do need a structural bridge engineer after all 8-)

Thanks guys!! Keep the feedback coming - I'm taking notes!
 
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A 20' span is a heck of a steel beam. I would prolly opt for closer truss spacing (12" on center), with added bridging between them. The deck can be adhesived and doubled.

Another method of adding stability is a layer of gypcrete cement added over the floor. It makes for a solid platform without as much sway and vibration. If you're planning to have any tile work on the second floor, this is a great underlayment.

Best,
Mike
 
Check your local building codes for dead and live loads for the function I would use a conservative estimate of 4.8kPa for calculations of deflection. Joist spacing would affect only load distribution and can be compensated with larger beam sizes.

When you have selected the beam sizes, have your structural engineer do the deflection calculations under different load conditions, depending on your second floor layout I would place the billiard table in a room opposite your bed, so that it is balanced (if there is are columns taking the load in between) to reduce maximum moment.
 
Mike - thanks for the notes once again ---

Zerius - I will look into the various load calcs and deflections on beam sizes...appreciate it!
 
I went to the phone book and made a few calls, ended up using Robb Kullman, a local firm The engineer i worked with delivered plans with his Professional Engineer stamp (like a Notary Public embossing stamp) and signature. It cost me $500. I would not have received a building permit using free advice. I suggest that you look for a professional.

Dave
 
The way to go is to consult with a P.Eng. I would not trust the architects to make engineering calculations and know material properties and limitations. Building with wood is very sensitive to moisture, and designing a wood-steel structure is quite an art (accounting for variability in thermal expansion rates, expansion due to change in moisture content, just to name a few).

Although good architects can perform accurate calculations (some have an engineering background or have taken basic structural courses) sometimes you get what you pay for when it comes down to it all. Experience is often undervalued and in industry that is often the governing factor of a design.
 
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