I would like to hide these joints under some partition walls, because I may want to tile some rooms afterwards, and I don’t want to be committed to any certain tile layout…….. Some of these walls will be load bearing, and I want to thicken the slab beneath them. Is this OK? If it is OK to do this, how should the bottom plates of the wall land on the joint, if the walls and the joints run in the same direction?
Thanks for any help
Get expert guidance on finding a fixer-upper that's worth the effort.
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
Well,........ that didn't make a whole lot of sense, now that I re-read it. Sorry.
Let me try again.
I want to pour a slab and cut in some control joints. The bottom plates of some of the walls will cover the joints along their length. I want to hide the control joints. Is this OK to do? If so, should I let the bottom wall plate straddle both sides of the joint, or just run the joint along one edge of the wall ? Does it make any difference if a control joint is cut along a thickened section of a slab? This is a three story house.
I wouldn't worry about where your joints are. You can level them with floor leveler prior to tile or vinyl or whatever. They are only there to give the inevitable crack a straght path to follow without crossing the floor.
Cole
Cole Dean
Dean Contracting
If your control joint is cut along a thickened section of the slab it kinda defeats the purpose. Putting a weight on the joint pretty well quarantees the joint will crack there but doesn't mean it won't crack elsewhere either.
Control joints are located strategically in the slab and can be either filled with caulking or if you want to have any tile pattern over them you can use an expansion strip to break the tile without breaking the pattern.
Gabe
If you're shooting the bottom plates or PL'ing them down, I'd avoid straddling the control joints. Go for one side or the other.
Let me get this right.....you want to place your planned wall partitions directly over the control joints so no one will notice them....OK.
So I guess you figure no one is gonna notice the cracks in your plaster or the nail pops in your dyrwall or the opening up of the miters (not to mention crooked headers) in your trim casings after these wall partitions shift ( ever so slightly) due to your placing the wall plates overtop a floor section that's designed to crack?
The last thing I'd do is place my control joints next to or underneath my planned wall framing.
Just my 2 cents.
Davo
Thanks all for the the inputs.
yeah, I know it sounds obvious, but I considered doing it that way, because if I don't have to use a crack supression membrane, then I would choose not to. It is just one more step that could go awry.
Also, in this particular situation, the load bearing wall will intersect at the inside corner of an elevator well- a likely prospect for a crack. I am thinking the best solution is cut the crack a half an inch or so away from the wall, and let the plate rest on the "edge" of the crack- same as it does on the exterior walls.- still should thicken the slab underneath though, I guess.
how should the bottom plates of the wall land on the joint
One one side or the other, not down the middle. A half-inch joint will "hide" under the plane of the wall board without too much trouble. There's already a joint there between floor and wall which will hide any miror changes. A cut joint is even easier to deal with.
Either way, you avoid problems with the plate fasteners falling on, or too close to, the control joint. Not much point to put in the CJ if you are going to run in a compression anchor and bust the joint when it's tightened.
I would put the control joints per the structural schedule, which in my neck of the woods is about every 8 feet. I would not be too concerned about their placement.
If you are concerned and want to deal with tile layout now, which is actually a good idea, then I suggest you sit down, and figure out your tile layout now, and place the control joints accordingly.
Most control joints are place in doorways, so the tile transition slip or a wider grout line (actually should be caulked) is less noticeable.
You do not want to membrane over a control joint. The TCA manual requires us to respect the control joints and take them right up through the tile. We stagger grout lines on them, and caulk between them. If an additional setting bed is laid over the control joint. It stops at that joint and backer rod is placed into the gap (the foam thingies, OK?).
If you want to run tile on the 45, there is no problem with running the control joint at that same 45.
There is a school of thought that one can membrane over a control joint, but not an expansion joint. A control joint is merely a tiny space in the slab generally formed by hand, or sometime with a form. It does not generally go through the whole of the slab. It allows the slab, indeed encourages the slab to crack at that point because it is so thin. They are every 8 feet or so in my neck of the woods.
An expansion joint is joint separating two distinct slabs formed at different time. A true cold joint. It is filled with backer rod. It allows the slab to expand and contract at will along the joint. They are about every 20 feet in my neck of the woods.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934