There is floor bounce in my 1955 ranch which is 1250 sq ft
It’s noticeable when someone weighing say 250 lbs and more walks across the floor
I notice it when my son walks across the floor
I don’t think an avg person weighing, say 150 lbs, will cause any bounce
Anyway, the house has a crawl space and I got a light and went under to investigate this morning
Here’s what I found
2 X 10 floor joists on 16 inch centers
floor joists are supported by exterior foundation and also an I beam setting on two piers.
There is a second I beam as well.
The I beam is made of about 8 inches of very heavy steel
There is a 2 x 4 on top of the I beam and it is bolted to the I beam
The floor joists are toe nailed to the 2 X 4 on top of the I beam
Everything seems to be tight: the floor joists tight against the 2 X 4, and the 2 X 4 is tight against the I beam, the I beam is tight against the concrete piers.
The 2 X 10 floor joists span about 13 ft. there is bridging in place
There are 1/8 inch thick steel plates between the I beam and the top of the concrete pier.
Conclusion: There is nothing I can do about the floor bounce
there is no easy simple way of strengthening what I already have in place.
Does anyone see any easy & simple way of adding strength & stability to the flooring structure in this house?
Thanks for any suggestions
Replies
mr,
Reduce the span of the I beam. Crawl under and see what's moving while your son walks-bounces on the floor. I see lots of simple ways to reduce bounce depending on what is moving.
KK
There are several potential solutions- sistering (some) joists; running a "strong back" running a 2x4 along the bottom of (some) joists, etc.
Try a forum search for --sister joist--
"Ask not what the world needs. Ask what makes you come alive... then go do it. Because what the world needs is people who have come alive."
Howard Thurman
I agree. Ya gotta get under there when a big feller walks across the floor to see where the movement in most pronounced.
What kind of bridging? Metal or wood? The metal strap type isn't very effective unless each piece is bent properly, pulled tight and nail correctly.
I'd do as others suggest, get under there again with your light while junior does a flamenco dance overhead. Have a good look at how the bridging is reacting too.
Edited 12/9/2008 8:55 pm by Hudson Valley Carpenter
The bridging is 1 x 4'sThanks to everyone for their suggestions.I guess I was expecting someone to say something like "there are limits to the amount of weight a 2 X 10 can hold"My son may be getting up to 275 or maybe even 300 lbs - I'm not sure. But He needs to go on a dietI'm guessing when people get too heavy and overweight they are going to cause even a 2 X 10 to bounceAm I right in saying there are limits to what you can expect from a structure?If someone weighs 300 lbs they are probably exceeding certain limits.Thanks again everyone.
I'm guessing when people get too heavy and overweight they are going to cause even a 2 X 10 to bounce
Am I right in saying there are limits to what you can expect from a structure?
The bank where I have my accounts, in a modern high rise building here in Los Angeles, is on a rolling, earthquake resistant foundation of some kind. When a person of your son's dimensions walks across the bank's floor, everyone can feel a substantial movement, something akin to an actual earthquake.
I wouldn't worry about the floor's bounce, not until you hear something crack loudly.
I weigh 280 pounds. I don't like dishes rattling etc. so I used 2x12's 12" O.C. (actual not nominal) that's to span 9 feet. Plus mid span blocking I've one section where I have to span 15 feet so I sistered every 3rd joist with a 3x12 ash beam and a center beam of 6x12. I can still get a little bounce so I'm putting a mid span built up beam in place. My stairs all have 5 stringers in them made of 2x14's sub flooring is 2x12's
My son is heavy enough that he sat on a brand new (albeit inexpensive) chair in our home and he broke it.The legs just kind of collapsed underneath his weight.Frenchy it sounds like your house must be solid as a rockI'm tempted to just simply attach a 2 x 4 to the floor joistsI would place it in the middle and use long screws through the 2 X 4 and into the 2 X 10 floor joist (the 2 x 4 would be kind of like strapping perpendicular to the floor joists)I'm just wanting to try something easy and inexpensiveI wanted to thank everyone for their suggestions and I apreciate the suggestion that I have him walk across the floor and see where the bounce is occuringI'm wondering if the outside foundation perimeter is moving up and down and this results in the middle of the house raising up off the structural system.Thanks again everyone
Edited 12/10/2008 9:27 am by mrfixitusa
Don't know if you've read the thread on floor vibration. It might help explain what's happening:http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=21010.1It sounds to me like your 2X10s aren't over spanned, although they're close to what I'd like to see. The I-beam may be contributing to the vibration if it's marginal. No way to tell without knowing all the details about it. Adding another beam at mid span would make one heck of a lot of difference. But it doesn't sound like you want to go to that much trouble. Adding a 2X4 flat at mid span is the easiest thing to do, and it might help. But there's no way to predict how MUCH it might help.
Bumpersticker: When in doubt, shut up.
Thanks I read through it and a lot of it is over my head but it's interesting the various techniques and strategiesDid you know that some of the older houses were built with 2 x 6 floor joists?I lived in a house like that and what's worse is those floor joists were on 24 inch centersIt was an old old house with plaster walls. I don't know the age of the housesomething else to consider is I think people are fatter and heavier nowadays than they used to beThanks again
"...people are fatter and heavier nowadays than they used to be."
That's not something I had given a lot of thought to until this thread. But there's no doubt it's true.
Why do they call it an asteroid when it's outside the hemisphere, but call it a hemorrhoid when it's in your........Butt?
it's amazing how stout you can build stuff when wood is cheap!
And it's amazing how annoying you can be when you keep bragging about your house and how you do things.
Do they ever shut up on your planet?
I apologize. I'm really not trying to brag, I'm trying to motivate others to follow my path. That is to look outside of the box. Be creative and seek other solutions when for fincial reasons they are excluded from normal answers.
Wood is available almost anyplace and it can be extremely affordable.. Look at pallets.. they are made cheaply but with good solid wood.. The sawmill that makes the wood for those pallets is where I would start to look for a good source of wood.
Don't let neh sayers hold you back, every building code has a section that allows alternate construction.
If I motivate a handful of people to build their own homes then I believe I've done a great thing.. Perhaps that handful of people will motivate others etc..
I realize this is and will always be a grass roots movement because nobody makes a massive profit off these deals. It pure and simple is a way to acquire the things you want without all the commericalism and profitering involved in normal construction..
On the other hand work like this will keep you out of bars and from wasting your life in front of a TV. I realize I sound a bit evangelical constantly preaching but I know there are many lurkers out there and we get new ones every day. Hopefully enough will either ask me details here or via E-mail and I can continue to make it interesting..
Again I apologize to you old hands who see this stuff repetively and hopefully you now understand why I do it.