Hi everyone,
I need to double my floor joist in order to replace a carpet with tilels. There’s a full basement and easy access. Will I need to jack up the house for that? and any advice you can spare, will be great. thanks. Mirav
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Why would you think that you have to jack up the house? Your putting in the same size joists with easy access, right?
yes, the same size joist, but since I'm not the one who'll do it, I didn't think you can bang one in. Is that's how it's done?
Maybe you're thinking you've got to jack to take out a visible sag? If so, do it this way.
Cut the new joists just long enough to fit in the pocket on the plate on one side, then swing up on the other side. They won't swing all the way up because of the floor sag. Jack up that side with a little bottle jack, then drive lots of 3" Truss-Lok type screws through both old and new joists.
I'd start in the middle of open floor spans, to sort of creep up to the walls along either edge. Solid blocking is nice to add about now.
Remember, deeper joists are one heck of a lot stiffer than just more joists. Stiffness goes up as the cube factor of the beam depth.
Forrest - done this lots. Most time-consuming part is moving plumbing and/or wiring and/or ductwork
no sagging, but I didn't know you can bang one into place and have it deep enough w/out jacking up the house. I'm onlythe home owner, not the one who'll do it. But needed to know what ittakes to do it.
Well, it's not important to really bang in one end - it's just to support one end while you jack the free end.
You might be confusing "strength" with "stiffness". You can just sister a joist and never go within a foot of either end where it bears on the plate, and still have a significantly stiffer assembly - your floor isn't too weak now, its maximum center deflection is just probably L/360, rather than L/180 or L/120 (where "L" in the span, in inches).
I believe residential 40psf live/ 10 pdf dead load joist tables are designed to meet the L/360 number. That is, a room 15' wide (180 inches) will deflect 1/2" (180/360) in the center at maximum loading. Tile won't take that!
Forrest - always go with a bigger joist
I like to use LVL's ripped to the joist height. You can beat the crap out of them without splitting like dimensional lumber does.
Used this alot when plumbers or other subs decide a drain/heat duct is more important than the house standing.
Has your builder looked at the possibility of halving your floor joist spans by installing a stout beam perpendicular to the joists, at mid-span, and held up by posts? This is an option in an unfinished basement.
This will greatly reduce your deflection, with less lumber, and depending on where the pipes/ducts/wiring etc. are, may be a faster-cheaper too. Since your basement is not finished, adding a beam may be an option, esp. if you don't intend to finish the basement in the future.
Regardless, you would not 'jack up the house', you would only jack up the floor to take out any existing sag. If there is a wall above the area you are jacking, there may or may not be some loads in that wall, and there may or may not be some implications in terms of slight drywall damage in the floor(s) above.
great advice. thanks.
Mirav
How long are the joists?
What are they o/c (how close together)?
Do both ends sit over foundation?
Edited 3/11/2007 8:05 pm by 1muff2muff
I think both ends sit on the foundation, have to open one wall to see. Currently the joists are 12" apart and they're 2X4
<Currently the joists are 12" apart and they're 2X4>
2x4?
Is that a typo? or are your floor joists really 2x4?
Or is it really a floor?
Perhaps the carpet is on the wall.
they are 2X4, no typo. why?
they are 2X4, no typo. why?
Because if they are spanning more than about ... oh, say ... 3 ft, then they are incredibly undersized to be a floor joist. Even with 12" OC spacing like you mentioned, they are just not the right size.
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
"I think both ends sit on the foundation, have to open one wall to see. Currently the joists are 12" apart and they're 2X4"
Eeep! How far do they span?
under te entier house wich is 1200 sqf
Greetings miravozeri and Welcome to Breaktime.
If you have a house with 2x4 floor joists then this is a serious situation you are speaking of.
It would be very prudent of you to make a very detailed description of your first floor for the benefit of the readers and yourself in that you are needing some important information.
In fact, it would serve you well to take some photos of the framing and post them here for clarification of your situation as so far the description given does nothing but raise additional questions.
Mentioning what state you are in might be helpful to possibly identify a particular building style as well as if you can give the estimated age of the house and any other building characteristics in the home.
I'm guessing being a first floor with 2x4 joists might mean there is a custom style grid of beams they are sitting on or something to that effect.
Seriously if you are planning a tile floor then posting pics here will be advantageous to you.
Cheers
every court needs a jester
hi there,
The house is in Saugarties NY. I don't know all the details, since I only saw it during the inspection. Im closing on the house on Friday, and will be able to give more info, once I'm in.
Thanks
Mirav
Ok, we'll all be waiting here for clarification of the 2x4 flooring joists mystery.
be a modernday Tom Swift/Nancy Drew
every court needs a jester
Yep, this one's gonna need closure...
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
perhaps instead of 'joists' she has trusses made with 2x4 chords.
My brother just uncoverd the same thing but it was his attic floor. He called my up to come over and give him ideas. The attic is finished area. I told him it was not a good idea to just sister them and came up with a plan to at least use 2x6. He said it was to much trouble . I asked him why he called me to come over.
You have a major problem! Unless there is some sort of other suppport grid of beams, those should be at least 2x8. Somebody asked what these span and your answer was to give total square footage. Span is the distance horizontally that these are free of support under them. at 12" oc, it should be no more than about 4' for any floor, even less for tiule.How did you come to the conclusion that you need to double them up?
I am assuming the tile guy took a look and told you to do something about the problem....Tile cannot have as much flex in the structure as carpet because it will crack or come loose.I've never even seen a floor with only 2x4 frame in 35+years of construction and remodeling!
Unless you count mobile homes.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
the distance between joist is 12" and I was told to double them, for tiles, by the guy who did the inspection. I will do the tile work myself, done a lot of it in the past.
Forget in between the joists. What is the length of the joists from one side of the foundation to the next? Also is there a girder underneath mid-span to break up the span of the joists?Joe Carola
don't know the answer, will be more educated on Sat. will post it again then.
Thanks
my mistake, you guys were all right,called the inspector, the joist are 2X6 or 2X8, they had insulation in between them he said. My mistake. Sorry.
There's still a big difference between 2x6 and 2x8. The 2x6 are still undersize for floor joists. This whole story sounds like you're buying a pig in a poke."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
No problem miravozeri, we are here to help ya.
every court needs a jester
What's going on? Did he close? how big are the joists? Been followin' this,kinda want to know what happened.
Hi there,
So thewhole thing was wrong, finaly got in the house and lo and behold the joist are 2X10 with 12' between the support beam, which is why the inspector thought I should double them. So it's not as bad as I thought.
Hi there,
I closed on the house and was there w/no internet connection therefore couldn't update all you, great guys, that gave megreat advice. The joist are 2X10.
Since this hasn't been mentioned yet, you might try out this deflection calculator. http://www.johnbridge.com/vbulletin/deflecto.plI think this will give you a fairly good idea of what kind of structural support you'll need to put a tile load on top."anyhoo ... to any of the girls here who can't hit a nail with their purse .... ever think of actually trying ... and practicing ... instead of looking to see which screws match yer shoes?" ~ Jeff Buck 3/13/07
No - you still misunderstand the question.
I know they are 12" OC layout.
What is being asked is long long the span is from one bearing ppoint to the other.
In other words, if the house is 24' wide with one beam in the center, the span is 12'. If there are the two outside walls and three beams bearing the joists, then the span is 6' if all equal.From what little is known now, I think your inspector has done you a great dis-service. He should have thrown up great big red flags on this kind of thing instead of proposing a half azzed fix. As a matter of fact, doing engineeering like this is outside the scope of an inspector's job.Nor do I believe that there is no sag in this floor. Before closing on this property, you would be wise to drive up there immediately and check for yourself. Any house that was built with 2x4 for floor joists has a 95% chance of other failings because it is obvious that the builder either was a schlock or a hack or a con man and any of the three will have done other things wrong too.or maybe it's just a typo on the inspectors report.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Bob, can you take a look at this thread?
OP buyer is days away from closing on a house with 2x4 floor joists that an inspector says will bear a tile install if only the 2x4s are sistered up....with more 2x4s.
Mira: I'd try and buy some time before closing on this one. At the very least, get another inspection from an independant home inspector - independant of the realtor and seller that is.
If ever there was a call for napalm!!!Wars of nations are fought to change maps.
But wars of poverty are fought to map change.
yep - maybe the OP will get lucky and it will burn before closing
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I kept waiting to get to the punch line thinking this was a joke.
Me thinks if he hasn't closed on the house yet, he shouldn't...
Did he have the house inspected? What were the inspectors thoughts? lol and what else did he find...
Must be a real gem.
Unless like you mentioned it at one time had wheels.
Unless you count mobile homes.
Well, they are often 2x3, but clear, stud-grade, 2x3, usually middling ridgidly fastened to the subflooring to make a membrane-type structure.
I sure hope OP's joists are headered off in all sorts of ways.
Which makes me wonder if, long ago, the bathroom might have been tile on thick-set mud, and the joists were reduced in height for the mud bed? Pure-D speculation on my part, though . . . Occupational hazard of my occupation not being around (sorry Bubba)
McDesign has given you an excellent way to re-enforce your floor, if the joists are 2x4, EEEK, you've got a huge McProblem. Please verify the joist size so everyone here can sleep tonight.
I wonder if , before you're house had a basement, it didn't have a steel frame on wheels..?
What year do you think it was built?
it was build in 1973.