Framing a floating wall in basement?

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  #1  
Old 11-02-05, 03:44 PM
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Framing a floating wall in basement?

Apparently code in CO requires that I frame "floating" walls in the basement. Anyone know where I can find detailed instructions about doing so?

I guess there are soil settlement issues. Thing is, my house 40 years old and it seems to me that if it hasn't settled up or down by now, it probably won't. Also, the previous owners framed a few walls the old fashioned way.

But I guess to be legit I'll have to do the floating walls. Any advice appreciated. Thanks!
 
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Old 11-03-05, 08:24 AM
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I live in CO also... and just finished a new basement addition. Due to the nature of the soils... floating walls are "code required". It's not difficult... just a bit time consuming.

I laid my treated floor plates just as you would any other framing installation. On top of that I put 1 1/2 inch spacing blocks. On top of those I put my new "floor plate"... nailing them in with spikes to the first "floor plates". Once secured, I removed the spacers - and continued with the normal framing. This ensures that, should your basement floor rise, it won't lift the next level off the basement walls....

By the way... if your inspector notices the other walls that are improperly done.... he can, and possibly will, make you re-do those also....
 
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Old 11-04-05, 04:40 PM
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Robb,

Actually it is a lot easier to do it the other way around. Make the space at the top of the wall. Code in my area also requires a space, mine calls for approx. 1". Build the wall short by an 1" (1 1/2" if that is your code requirement), attach the bottom plate to the concrete floor (remember to use pressure treated wood) then get it plumb & straight, then drive your nails / spikes up into the floor joists above it. Its a lot eaiser that way. Build the wall on the floor then just tilt up. Remember it is a basement, its non-structural, and not going to go anywhere. Also if you use a hung ceiling then you do not have to worry about the drywall cracking from any settling or heaving since the gap is at the top & probably above the hung ceiling.

Good luck.
 
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Old 11-11-05, 12:55 PM
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Thanks for the advice. I actually like the idea of the gap being at the top, because then the weight of the wall (with drywall and everything else) won't be hanging from the ceiling. Seems to make sense to have it rest on the floor. I think this is the way I'll do it, assuming I'm allowed to. Will check.

Thanks!
Robb
 
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Old 11-11-05, 02:02 PM
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Good idea...

Check with the permit office.. I agree that the "space at the top" method sounds just as good and easier... but, if that's the case.... whyforhowcome all the homes here in Fort Collins have the gap at the bottom? Lemme know if you find out....
 
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Old 11-11-05, 02:38 PM
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I've never seen the gap at the top, but I'm certainly hoping it's allowed. Will post findings.
 
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Old 11-30-05, 08:35 AM
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Top vs. Bottom gap

I'm in Fort Collins and am just getting started on my basement as well. Having moved here from Wisconsin, the whole floating wall thing kinda freaked me out at first. Here's a few things I've learned from talking to a bunch of people and doing some research:
  1. Most of the time, the gap is at the bottom because the baseboard will cover the gap. (Keep in mind that it isn't just the framing that has to have the gap - drywall as well.) If you put the gap at the top, you either need to use a drop ceiling or put up crown molding to cover the gap if it's a drywall ceiling.
  2. Surprisingly, the floating wall will hold it's own weight as well as shelves, cabinets, etc. just fine. This kinda surprised me. Several contractors I've talked to, though, have recommended using screws every few feet in addition to the nails to help hold it up.
  3. When you frame up your doors, leave extra space between the top of the door and the header.

The part I haven't figured out is how to deal with the bathroom plumbing to account for the possibility that the floor could rise or fall. It seems to me there will need to be some "flex" in the drain system to account for this but I haven't found anything specifics.
 
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Old 01-03-06, 01:38 PM
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steel stud floating wall

I’ve been told (by a professional contractor) that there is an easier way to build a floating wall with steel studs. From what I could understand, the wall floats from within the TOP plate using a longer flanged track. This sounds easier then the more traditional attach pressure treated lumber to the floor, create your float, and then frame. I belive this also eliminates the need of having a gap at the top of the ceiling.
 
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Old 10-10-09, 09:02 PM
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floating wall with door

Originally Posted by dukescotts View Post
I'm in Fort Collins and am just getting started on my basement as well. Having moved here from Wisconsin, the whole floating wall thing kinda freaked me out at first. Here's a few things I've learned from talking to a bunch of people and doing some research:
  1. Most of the time, the gap is at the bottom because the baseboard will cover the gap. (Keep in mind that it isn't just the framing that has to have the gap - drywall as well.) If you put the gap at the top, you either need to use a drop ceiling or put up crown molding to cover the gap if it's a drywall ceiling.
  2. Surprisingly, the floating wall will hold it's own weight as well as shelves, cabinets, etc. just fine. This kinda surprised me. Several contractors I've talked to, though, have recommended using screws every few feet in addition to the nails to help hold it up.
  3. When you frame up your doors, leave extra space between the top of the door and the header.

The part I haven't figured out is how to deal with the bathroom plumbing to account for the possibility that the floor could rise or fall. It seems to me there will need to be some "flex" in the drain system to account for this but I haven't found anything specifics.
About the door solution.If u leave more space at the header your stil attaching your door legs to the studs and your door is on or very close to the concrete slab, so if the slab moves then your door will also move and move the studs with it?
 
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Old 10-11-09, 09:47 AM
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Welcome to the forums! It's a 4 year old post.
 
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Old 01-16-11, 03:03 PM
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How close do you add a floating wall to an concrete outside basement wall?

I'm also putting in floating walls, but have never done this kind of thing. How close can I construct the wall to the concrete basement walls (outside walls)?
 
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Old 01-16-11, 03:33 PM
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Welcome to the forums! I would hold the wall about an inch away to allow for air movement behind your framing to keep down on condensation.
 
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Old 01-17-11, 06:13 AM
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Thanks.

Thanks, Chandler. There's a plastic wrap on the concrete walls with insulation behind it. Does that make any difference?
 
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Old 01-17-11, 07:54 AM
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No, that's your vapor barrier. Any moisture between the vapor barrier and your lumber needs to dissipate, therefore the 1" spacing.
 
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Old 01-18-11, 05:17 AM
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Okay, thanks Chandler! Good to know.
 
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Old 05-05-11, 08:19 PM
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Sorry to bump an old thread, but I figured it was better than creating a new one.

I live in CO and started working on finishing my basement. Does anyone know if floating walls are still required for a house without a concrete slab? I have a plywood subfloor and dirt about 3 feet below. All my walls are going to mounted to the subfloor and metal joists below it. Any help would be appreciated.
 
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Old 05-05-11, 09:24 PM
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If the dirt is 3 feet below the subfloor, I can't imagine why a floating wall would be needed. The whole point of the floating wall is to prevent problems if the slab should rise. It's definitely not going to rise 3 feet.

Still, probably doesn't hurt to check with your local inspector.

BTW, I'm extremely jealous. I'd love to have a subfloor in the basement instead of a slab.
 
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Old 05-06-11, 03:40 AM
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I think the dannyboy has a crawlspace with normal framing, not a basement. Not sure how you would treat a basement floor system not on a slab. too much moisture.
 
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Old 05-06-11, 07:19 AM
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I'm pretty sure I'm okay with not floating the walls since the subfloor is in place. I've heard a few horror stories about having to tear walls back out to float them, so I definitely want to avoid that. lol

The subfloor is great to work around. Plenty of space under there for plumbing and electrical. Best part is going to be that my options for flooring down there will be a little more available without worrying about movement.
 
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Old 05-06-11, 07:23 AM
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Originally Posted by chandler View Post
I think the dannyboy has a crawlspace with normal framing, not a basement. Not sure how you would treat a basement floor system not on a slab. too much moisture.
Its definitely a basement. Metal joists off the foundation and the plywood is mounted to them. The dirt floor below this subfloor has a vapor barrier to prevent moisture. My ceilings in the basement are at least 8'.
 
  #21  
Old 05-06-11, 03:00 PM
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They're not required with what you have, which is called a structural floor. They still are required on a concrete slab. The reason is from expansive soil in Colorado called 'Bentonite'...it's like a clay that swells when it gets wet. If the walls don't float it will literally push the house up and do a lot of damage. I frame basements all the time in the Denver area and the minimum 'float' is 1 1/2", but I go 2 1/2" just to be safe. Don't forget to put in the firestop at the exterior walls.
 
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Old 05-06-11, 06:25 PM
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Originally Posted by gwawoodworks View Post
They're not required with what you have, which is called a structural floor. They still are required on a concrete slab. The reason is from expansive soil in Colorado called 'Bentonite'...it's like a clay that swells when it gets wet. If the walls don't float it will literally push the house up and do a lot of damage. I frame basements all the time in the Denver area and the minimum 'float' is 1 1/2", but I go 2 1/2" just to be safe. Don't forget to put in the firestop at the exterior walls.
AWESOME! Finally an explanation for floating walls. A good one at that.
 
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Old 05-08-11, 10:50 AM
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I understand it has to be done, but my "physics" mind won't allow me to understand why the clay soil eruption won't just lift the entire house, footing, slab, everything, thereby eliminating the need for a floating wall. I have done the floating wall, too, and do as described gwawoodworks. I just can't wrap my mind around the theory. Where is the separation? between the walls and the slab? Why doesn't it leak? Not being contrary, just seeking information as always.
 
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Old 05-08-11, 01:06 PM
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Maybe because the weight of the house on the soil directly below the footings prevents the soil from expanding as much as the soil under the slab that doesn't have all that weight on it.
 
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Old 06-03-11, 12:00 PM
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I understand why we need floating walls here in Colorado but it is completely ruining my ability to build a soundproof room. I am wanting to build a music studio/practice space and having a 1 1/2 in gap at the bottom of the wall that I can't completely seal off totally defeats the idea of having a completely sealed up room. Soundwaves are like water in that if there is breached space they will find it and flow through it.
 
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Old 06-03-11, 04:44 PM
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You can close it off with tall molding, you just can't attach the molding to the wall, only to the base part. The wall has to slip behind the molding. Caulk it well, and if it settles, what the hey! Caulk it again. I don't believe code will allow you to insulate that space, however, only above and below it. But covering it with tall molding should help some.
Same problem building darkrooms. Light is even less "viscous", for lack of a better term. Stand in a darkroom after you have built it, close the door and the light is deafening!! You'll learn to close them up quickly. Probably the same with sound.
 
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Old 12-20-11, 11:07 AM
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How do I secure a floating wall to not sway

Hi all! I've read this thread and use this site a lot but this is my first post. I am framing a bathroom in my basement and want to follow the code by doing floating walls, but had some concerns.

#1.The floating wall will need to support the weight of backer board and tile so should I use nails + screws to secure it at the top? Or should I use the "gap at the top" option? I'm incline to go with the latter option because I will have more standard framing at the bottom to rest the shower pan against.

#2. I don't want to wall to "sway" AT ALL because any movement could crack my tile grout and introduce moisture behind it, so how to ensure that it doesn't do that? Are the stakes really enough to prevent that?

#3. Does anybody have any drawings/images showing how to incorporate a doorway into a floating wall? I saw that part of the threat, but I still can't picture it. Wouldn't the door closing loosen the stakes over time and cause the wall to sway?

Sorry if these are stupid questions, but those are the pieces I still don't understand after reading as much as I can find about it.

Thanks!

~Zach
 
  #28  
Old 12-20-11, 01:04 PM
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Zach, if you can do it with the gap at the top it is alot easier. With the gap at the top & using longer than normal nails your wall is not going to move. The 1" gap at top really made construcing the wall easier. If you are worried about it, just use more & thicker long nails / screws. You can over-do-it if you want & use 4-5" lag bolts from your top plate to your joist above. That & tying in the corners with each other will be more than enough.

Same thing for doors. I have kids & with slammed doors or teenage boys rough housing in the basement still no problems with any of my walls (drywall or mud & taped areas).

Again I have my gap at the top thus I do not have to support a free space at the bottom. I have a drop ceiling so again not a problem with the gap at top. If you have a drywall ceiling, then plan to use crown moulding to hide your gap at the top.

Good luck, build it right & you will be just fine.
 
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Old 12-20-11, 06:31 PM
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Awesome. Thank you. I think I'm going to go with that top gap. Sounds much easier and I don't mind putting up crown molding.

Thanks again!
 
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Old 12-20-11, 06:56 PM
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Shoot. I didn't think of something. How can I have a gap at the top if I'm installing a shower that will have tile to the ceiling?
 
  #31  
Old 12-23-11, 07:48 AM
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Zach, sorry for the delay, I had a password problem with the site.
How much is this shower going to be used & what type of ceiling are you planning? Also how much water do you expect to spray upwards in that shower? Look after you take a normal shower, not much goes up there. Mine is an extra shower for the house & only gets used 2-3 times a year at most. Thus I am not too worried about water & mold around it. Are you installing an exhaust fan? Most codes require it, I have one but it never gets used. That will help with water vapor if the shower is used a lot.

My inlaws basement shower is used daily, it has a hung ceiling where the tiles are more of a water resistant type just in the bathroom area. 20 years later they have had no problems, just a little rust just now showing up on the ceiling runners & cross T's and that is only above the shower area.

In your case, for a hung ceiling no problem. Just tile up to the gap area (not above it) then hang the ceiling down to your needed height below the gap area. For a drywall ceiling again tile just up to the gap area, then find some moulding you like and hang that down from the ceiling (attaching to the ceiling) then use latex caulk to caulk the small seam between the two. If (big if) you get movement, just re-caulk it in a couple years. You can get creative on the type of moulding you want, even use exterior type Vinyl moulding if you like it. Paint the ceiling & moulding with a mosture resistant / bathroom grade paint.

Good luck & keep building, it will be done sooner than you think.
 
  #32  
Old 12-24-11, 03:45 PM
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One thing to think about if you are going to have the gap at the top rather than the bottom is the sheetrockers work from the top down. It's a royal pain for them to have to deal with the gap at the top. Of course if you're planning on doing the sheetrock yourself, it doesn't matter as much.

Don't be afraid of hanging the wall with the gap at the bottom. It sounds weird and I'll admit that I was skeptical when I did mine. Once everything was up and in-place, though, the walls were rock solid. No problems with tile in the bathroom, lots of wall cabinets, etc.
 
  #33  
Old 12-31-11, 08:23 AM
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This is my first post! We just bought a house in Colorado and the slab is severely out of level (over 3") due to the pressure of the soil. It is slab on grade except in an addition that has a crawl space which is in fine shape.
We plan to remove the walls, bathroom and kitchen fixtures then decide how best to "fix" the slab. There is already a sump setup but it appears that the water collected is from the outside french drain not inside. We could put an inside french drain in and then level the slab. Or we will remove the entire slab, put in radiant heating, prep the soils for the bentonite, and re-pour the slab.
There is some cracking--at its most severe, about an inch separation from the rear side wall and then some cracking across rooms katty corner from each other and at the edges. (Evidence of heaving in the slab.) Also the block walls have a couple of stair step cracks but the foundation seems good. An engineering opinion was that the walls have cracked because the slab is not separated from the foundation and has pushed against the walls cracking them--he recommended removing the slab and the underlying soil, treating the soil for the conditions found under the house, and a replacement slab that should be isolated from the foundation by expansion joints and the walls rebuilt to be floating according to current code.
We are experienced at home remodeling and have built our own house with a slab on grade in the past, so we are excited about this challenge. It will be a lot more expensive to replace the whole slab than to run the drains--what would you do?
 
  #34  
Old 06-12-12, 03:20 PM
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floating frame wall

My contractor friend did provide 1 1/2" for the expansion - floating wall. But I was looking at the finishing basement guidelines for the Douglous county and it said it should be 3"! Now I have already completed and I am about to submit for permit. Are the inspectors strict about his guideline? If so, I have to take it out and again frame it with 3" instead of 1.5"... . Any suggestions? with regard to experience from inspecors?
 
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Old 06-12-12, 04:30 PM
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Welcome to this ancient thread and the forums! Your contractor needs to come back and do the job right. Yes, your inspector in Douglas county will probably hold you to the flame. You may get by cutting the nails from the bottom of the upper studded wall, removing the 2x4 plate, cutting each stud another 1 1/2" and reinstalling the 2x4 and respiking it to the bottom half of the wall structure.
 
  #36  
Old 06-13-12, 11:40 AM
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Our home is in Douglas County (Castle Rock, CO) also and has floating walls in the basement. But the gap is only about an inch and a half. And this house was built by Richmond Homes, so I don't think they would have ignored code. 'vinbin' may want to double-check what they were told, because I've never seem a home here with a 3" gap. Just my two cents...
 
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Old 06-26-12, 08:12 AM
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nail hole size

What's the recommended pilot hole for the floating spike? I'm using 60d 6" common nails and I was told at the lumber yard to drill a 3/8" hole for the spikes. But the diameter is slightly bigger than the nail's diameter so the walls "moves" and "sways" a little bit, especially when you bump against it. Is this standard? Or should I be drilling a smaller pilot hole for the spike in order to get a more snug fit and prevent that lateral movement?
 
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Old 06-26-12, 06:34 PM
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Spike hole

I drilled a 1/4" hole through both plates then went back through the upper plate with a 3/8" hole and drove my nail in. Figured the bottom plate would hold the nail secure and the wall could slide on the nail with the bigger hole in the upper plate. If 3/8" is too loose try 5/16".
FWIW code here in El Paso county Colorado calls for a 3/8" hole.
 
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Old 06-26-12, 06:47 PM
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Hang a wall from a soffit?

I have several walls that I plan to build under a soffit in the basement. Code says to build floating walls, but my concern is if there is enough strength in a soffit to hang walls from it. Does anyone have experience doing this or known if it is even permissible? The soffit will be 5.5' wide in places where I will hang walls in the middle of and parallel with the soffit.
 
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Old 06-28-12, 02:13 PM
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re: Spike

@ whattodonow: Makes sense, good advice. Many thanks!
 
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