|
View previous topic :: View next topic
|
| Author |
Message |
monkeychild
Joined: 22 Mar 2008
Posts: 7
|
 Posted: Sat Mar 22, 2008 5:04 pm Post subject: Will my floor collapse? |
    |
|
Hi all -
I'm building a large wooden structure (for the sake of simplicity) in a bedroom on the upper floor of my house. By itself, it weighs roughly 900 pounds. It's spread over an area of about 48 square feet...... 2 walls of the room are exterior walls. In case it matters, or anyone's interested, my house was designed by Ralph Rapson...
Is there any way my floor could collapse from the weight? If so, what are the warning signs and what can I do about it?
This is a serious question. Sorry if it's in the wrong forum.. I don't know much about this subject. Also, if you need more info to answer the question, I probably have it but didn't know to put it in.
Please, please reply if you read this 'cause chances are you know more than me.
Thanks,
Monkeychild 
p.s. I hope I'm just being a worrywart and 900 lbs is on the wrong order of magnitude... think 2 very fat people in one room. But i'm worried that over time, something will weaken. Thanks again! |
|
| Back to top |
|
 |
Madimel
Joined: 06 Feb 2008
Posts: 138
Location: Scottsdale, Arizona
|
| Posted: Sat Mar 22, 2008 10:25 pm Post subject: |
|
|
Monkey,
By your estimation, you are adding 18 pounds/sf to the floor structure. That is essentially a non-issue structurally provided the weight is spread evenly over the 48 sf area that you mentioned. I have the a couple of follow up questions for you before you start your project. How do you know the weight of the structure and where are the point loads of this project? Before you answer that, you should also tell us the floor structure. |
|
| Back to top |
|
|
monkeychild
Joined: 22 Mar 2008
Posts: 7
|
| Posted: Sun Mar 23, 2008 8:58 am Post subject: |
|
|
Madimel -
Thanks for replying!
Actually what happened, is I built most of the structure and then I realized there might be a problem. I really hope I don't have to take it apart.
Ok, I don't know what you mean by the floor structure, but my room is 15X12 feet.
Sorry, in advance for how confusing this might sound. If it doesn't make sense, I can probably send a picture.
The structure that I'm building (it's a climbing wall for training 'cause I'm a climber) is basically a box. It's sitting on a 5'X8' piece of 3/4 ply, and it's got 2 side walls that go up about 9 feet, and then a roof that sits on top of the side walls. Also it' got a back wall frame which is 8X10 feet, the 8 foot side being on the ground, and it's against one of the walls of my room that is NOT an exterior wall. Then there is a 8X8 wall that is anchored to the bottom of the back wall frame, sticking out into the cave at a 45 degree angle.
There is also an 8X6 foot roof that extends past the cave and is held up by a small structure on the other end of the room, touching an exterior wall.
There are 10 sheets of 4X8 3/4 inch ply.... plus some 2X4s and some extra hardware. THat's how I got my estimate.
-Monkeychild
p.s. all 900 lbs have been in this room for probably 6 months. |
|
| Back to top |
|
|
Madimel
Joined: 06 Feb 2008
Posts: 138
Location: Scottsdale, Arizona
|
| Posted: Sun Mar 23, 2008 4:44 pm Post subject: |
|
|
| Now I see where you got your log in name from, it all makes sense! Anyway, I wish it was that simple to tell you whether the structure will work or not just by a couple of simple post replies. But since we're not at your location to fully review the situation, we're guessing at best. When I asked about the structure of the floor, I was looking for the type of assembly. for instance, is it a steel deck with concrete floor? Are the floor joists set at 24" or 16" o.c., etc. There are tendencies for certain assemblies to move more when a load is applied in a concentrated area. When the structure experience a deflection due to the additional weight, it could cause havoc to your weather protection system. Chances of total structural failure is pretty slim, but that does not mean the additional weight will not pose as an issue. It will help if you can sketch up the structure with its adjacent rooms on both floors. And on your weight estimation, did you also account for the climber's weight? At any time, how many climbers will there be on this wall? |
|
| Back to top |
|
|
monkeychild
Joined: 22 Mar 2008
Posts: 7
|
| Posted: Sun Mar 23, 2008 5:57 pm Post subject: |
|
|
Madimel -
There will only be 1 or, at most 2 climbers on the wall at a time. It's a bouldering wall so it's not that huge..... and the 900 is on the safe side... that's including my weight. The room is a bedroom though, so it has a small desk, a closet, a small sink, a dresser..... generall bedroom stuff. It doesn't have a bed.
I read this article about waterbeds that said that you can sorta tell by walking roughly how sound the structure is. I doubt this, but when i walk in my room, or jump, or even fall from 10 feet up, nothing shakes, squeaks, nothing in the room rattles..... this is WITH the 900 lbs in it.
I'm pretty sure that the joists are 16 inches in my house.. the floor is NOT concrete or steel slab but my dad says it's a pretty solid house. It's wood on top but I don't know what's in it.
I don't know what our weather protection system is... but we've had moisture problems in certain places... but it's never been serious over this part of the house.... however, it has been in the vicinity. It's hard to say.
I can take some pictures of the wall and post them up here.... if that would help.
thankyouthankyouthankyou
-monkey |
|
| Back to top |
|
|
csintexas
millennium club
Joined: 06 Feb 2006
Posts: 1668
Location: USA
|
| Posted: Mon Mar 24, 2008 6:32 am Post subject: |
|
|
I think the "jumping" test is pretty good 
Most likely the floor is made of 2x12's spaced 16" on center. 18 pounds per square foot load is not unusual. If it was an abnormally weak floor for some reason you would feel it flex a bit. If it is a problem you would also most likely see drywall cracks in the ceiling below (if it has drywall) or at least some deflection.
Maybe where the stairs come up you can measure the thickness of the floor. Or I suppose you could use a thin probe like a clothes hanger wire up through the ceiling below to measure it's thickness and joist spacing just to be sure but I doubt there is any problem based on what you are saying. (even knowing the thickness of the floor would not give us certainty)
Without taking the floor apart and physically investigating it no one can say for sure though because it is still possible that there are other factors which we do not know about.
If it was overloaded you would most likely see the evidence long before it totally failed.
_________________
Chris Stewart
Modern Texas Home Project |
|
| Back to top |
|
|
carloramon11
Joined: 24 Mar 2008
Posts: 1
|
| Posted: Mon Mar 24, 2008 8:34 am Post subject: Re: Will my floor collapse? |
|
|
i want to start a structure much a like ! but not equal so if you can give a few tips would be awesome bye
| monkeychild wrote: | Hi all - I'm building a large wooden structure (for the sake of simplicity) in a bedroom on the upper floor of my house. By itself, it weighs roughly 900 pounds. It's spread over an area of about 48 square feet...... 2 walls of the room are exterior walls. In case it matters, or anyone's interested, my house was designed by Ralph Rapson...
Is there any way my floor could collapse from the weight? If so, what are the warning signs and what can I do about it?
This is a serious question. Sorry if it's in the wrong forum.. I don't know much about this subject. Also, if you need more info to answer the question, I probably have it but didn't know to put it in. |
Bulldog UK - Sheet Metal Machinery supplier |
|
| Back to top |
|
|
monkeychild
Joined: 22 Mar 2008
Posts: 7
|
| Posted: Mon Mar 24, 2008 9:17 am Post subject: |
|
|
csintexas -
Thanks! That makes me feel a lot better. I looked at my floor and it is indeed 12 inches thick. We have a stucco ceiling on the floor below but all in all there have been NO signs that anything is changing. It doesn't *feel* overloaded. The only thing we worry about is the possibility of moisture problems causing rotting wood in the exterior walls and in turn weakening the overall structure....?
The architect who designed our house, Ralph Rapson, lives somewhere around here..... I know my neighbor had him over for dinner one time.... maybe I should do the same. . . . hmmm. . . .
Carloramon11 - I can't quite understand what you're saying, but it sounds like you want tips on how to build a bouldering cave?
Are you a climber?
Happy climbing,
Monkeychild |
|
| Back to top |
|
|
JWmHarmon
Joined: 15 Apr 2004
Posts: 109
Location: Ohio
|
| Posted: Fri Mar 28, 2008 5:05 am Post subject: Weight of rock cave built on upper floor |
|
|
Forty-eight squre feet would be equivalent to a 6-foot by 8 foot area.
Nine hundred pounds is equivalent to six people with an average weight of 150 pounds. 150 X 6 = 900
Six people sitting around a 6 X 8 dining room table does not seem like an excessive amount of weight, even if they were to sit there all day and all night for years on end.
Six 250 pound football players would weigh 1500 pounds. 250 X 6 = 1500
900 pounds of rock climbing structure plus two 150 pound rock climbers would weigh 1200 pounds. 900 + (150 X 2) = 900 + 300 = 1200
_________________
When building or manufacturing always ask, "How will we recycle that?" - JWmHarmon |
|
| Back to top |
|
|
mx2
millennium club
Joined: 18 Jan 2006
Posts: 1906
Location: Miami, Florida
|
| Posted: Fri Mar 28, 2008 2:17 pm Post subject: |
|
|
It is not uncommon for these floor systems to be designed with 40psf dead load and 15 psf live load, although the safer engineer would design for 100+ live loads...a 12" thick floor system including finishes would suggest at least 10x's (9-1/4" bm + 3/4" plywd deck + lath and plaster/gypsum, etc)...don't know the span, but by shear guessing, I'd say you have a 50/50 chance of having to climb up from your basement one day....sorry, but that's the best non-asnwer I can give. If you're concerned, that's enough for me to suggest you get an engineer out to look at it or do what most climber's do...train outside. We're not equipped to give you a thumbs up...or down.
mx2.5
_________________
*Art of Architecture: The conscious use of skill and creative imagination in the production of an aesthetic building.
*Science of Architecture: The calculated use of technical skill and knowledge in the construction of a functional building. |
|
| Back to top |
|
|
monkeychild
Joined: 22 Mar 2008
Posts: 7
|
| Posted: Fri Mar 28, 2008 2:55 pm Post subject: |
|
|
mx2 -
I wonder, why do you say there's a chance of the floor collapsing when my load per square foot isn't even half of what the floor is designed to hold?
I'm wondering because so far you're the only one to respond this way and i don't quite get your reasoning.
thanks,
monkey
p.s. Are you a climber? Most climbers train indoors AND climb on real rock. Many many climbers build training walls in their house/garage so they can train on off-days..... when its raining....... when the local crag is covered in snow... when they can't find a partner....... when they have to work. I get out to the cliffs every weekend but you need more climbing time than that to climb hard. |
|
| Back to top |
|
|
mx2
millennium club
Joined: 18 Jan 2006
Posts: 1906
Location: Miami, Florida
|
| Posted: Sat Mar 29, 2008 7:36 am Post subject: |
|
|
Hey monkey, I did not mean to insinuate that I know anything about climbing...I was being sarcastic thinking it was a creative way to suggest alternatives to building this training module you've been working on.
But seriously, the simple fact is no one here, including yourself, can conclusively prove what the floor was designed for, let alone without seeing existing conditions, particularly at the connections, joists and decking. As I said, many residential floors are designed only for 40pounds per square foot. By very rough estimates you've assumed 900 lbs for your training wall but structurally it hasn't been clarified if it's spreading the load evenly or relying on point loads. For example, say its similar to a four post bed...four "feet" that touch the floor and the weight is centered (this is only an example) then your 900 lbs is distributed to the four points...resulting in 225 lbs per square foot...but if's cantilevered, even slightly, two of those points would jump even higher. And again, no one here has seen either your floor assembly nor the new structure your building. And I for one refuse to assume that all is just peachy and will always look towards safety first regardless of how much we all want to be positive about this. In the end, your project may well be extremely safe and well within the limits of your structure...but you don't know that for a fact. No on here does and I challenge everyone who posted here to prove it otherwise and end this. Please...prove me wrong, I even hope you embarass me, for the sake of safety. They should never had lead you down this road of insinuation and probabilities based on assumption without even once offering a caveat. I stand by my position, although I will certainly admit I know nothing of climbing and again apologize for assuming that climbers train outside. That wasn't my point anyway and I shouldn't have gone there...
mx2.5
_________________
*Art of Architecture: The conscious use of skill and creative imagination in the production of an aesthetic building.
*Science of Architecture: The calculated use of technical skill and knowledge in the construction of a functional building. |
|
| Back to top |
|
|
csintexas
millennium club
Joined: 06 Feb 2006
Posts: 1668
Location: USA
|
| Posted: Sat Mar 29, 2008 8:34 am Post subject: |
|
|
I think most all of us stated that this can't be determined with any certainty.
Even an engineer visiting the site could not make this determination absolute without taking the floor and lower walls apart and inspecting the soundness of the wood and it's connections.
That said, and knowing how a floor is typically constructed, We can say that there is an extremely low probability of total failure without any warning signs. Wood will deform before it fails and so you would feel some spring in the floor. That leaves the connection between the floor and the walls and also the quality of the 1st floor supporting walls and foundation in question.
So yes, if you want to be absolutely safe you should have the house rebuilt because we can't tell you whether or not it is about to fall on your head.
_________________
Chris Stewart
Modern Texas Home Project |
|
| Back to top |
|
|
monkeychild
Joined: 22 Mar 2008
Posts: 7
|
| Posted: Sat Mar 29, 2008 8:43 am Post subject: |
|
|
mx2-
Thanks for clearing that up - I definitely know that these responses are not for sure, and that no one here can see my house. the weight it spread very evenly over the area, and it's solid as a rock (no pun intended). I was posting on this board so I would find out if I was waaaaaaaay way off and didn't need to worry, or if I was in the margin of collapsing and should have someone look at it.
Climbers do train outside, a lot... but there are reasons for rock gyms too. I see you live in Miami..... there's absolutely NO real climbing in Florida but there's a nice rock gym in Miami called X-TREME: - the rock climbing center. You should check it out - climbing is so much fun!!!!!!!
csintexas - I know all that, like i said above, I wanted your oppinions.. and the weight is evenly distributed, the floor never creaks, nothing moves when I jump, nothing wierd is going on with the ceiling below........
Thanks all
-Monkeychild |
|
| Back to top |
|
|
mx2
millennium club
Joined: 18 Jan 2006
Posts: 1906
Location: Miami, Florida
|
| Posted: Sat Mar 29, 2008 10:55 am Post subject: |
|
|
LOL...yes, Miami is very, very flat...maybe I'll try my hand at climbing one day.
Chris, I don't know why you have to go from one extreme to other: "yes", it's fine to "no", you have to rebuild the whole house. As a professional you better learn quickly to be more to make safety your number one priority. There are many ways to verify that an existing structure is safe...and I usually take my structural engineer and poke around. Takes 10 minutes in the field and 30 back in the office. That's how I operate...no guessing on my watch, not on my projects and I deal with 100% existing conditions since I am now a historic preservationist.
mx2.5
_________________
*Art of Architecture: The conscious use of skill and creative imagination in the production of an aesthetic building.
*Science of Architecture: The calculated use of technical skill and knowledge in the construction of a functional building. |
|
| Back to top |
|
|
|
blogger
del.icio.us
digg
slashdot
