radiant concrete floor over I-Joist floor
Alaskahoan
| Posted in Construction Techniques on
I’m hoping to pour 1.5″ of concrete as a finish floor in my house. I’m hoping to cut 4′ on center relief cuts and a perimeter relief cut, but I’m hoping to put either #3 rebar or some other steel…mesh? to help reinforce the concrete from cracking. I’m putting in 1/2″ tubing in my floor, which I believe has an outside diameter of 5/8″. Anyone done this? and did it work? thanks
Replies
Deja vu
One thing I forgot on the other post... Be aware of the location for the pex when you are cutting. Assuming the pex is COMPLETELY secured to the sub floor with NO floaters, you can't cut more than 1/2" without hitting the clamps. Plate markings and LOTS OF DIMENSIONED PICTURES will let you get good 1" cuts where you need them.
I may be telling you somehting you already know, but - Make sure your floor system is designed for the added weight.
if it was designed for concrete then you should be fine with relief cuts. why are you wanting your cuts so deep? the steel is not necessary, simply to keep the concrete from moving when it cracks on larger applications. in your case when it cracks, its not going to try and slide or separate.
I second that...
I would use fiber mesh before using any steel reinforcement. I would also hesitate to cut very deep - it's a b**ch to expose the pex because you just nicked it. Even a 1/2" deep cut should provide enough of a path to relieve the stress by inducing a crack. Try to keep your joint pattern so that it creates rought square shapes....a 5'x10' pattern is virtually guaranteed to crack every 5'.
Something I can't figure out is why use concrete at all? It doesn't add much strength, and one could easily add furring strips between the tubing runs to support another layer of plywood. If it was judged necessary for heat conduction and thermal mass, sand could be placed over the tubing before the top plywood is fitted.
In the OP's opening sentence he said the concrete was to be a finished floor.
You need deep cuts
One must cut more than half way through the thickness of a concrete slab if you want to control cracking. Otherwise the slab had enough mass to crack wherever it wants to. If you are going to stain the concrete, don't use fiber. It will be harder to finish and the fiber near the surface will affect the coloring.
What?
MYBuilder wrote:
One must cut more than half way through the thickness of a concrete slab if you want to control cracking. Otherwise the slab had enough mass to crack wherever it wants to.
My Builder, where did you come up with those conclusions? I've never come across that specificaiton-- or even rough rule of thumb. To the contrary, I believe concrete never chooses where it cracks. It doesn't have a brain. Thus,it excercises no " free will" whatsovever.
Closer to the truth is that concrete cracks based largely on quantifiable geometeric and physical properties unique to each pour. Those properties primarily include material composition, reinforcing structure, curing conditions, and loading stress. The reason you see unsightly or random cracks in many finished concrete is usually because the responsible party for pouring the concrete is/was largley ingnorant of those properties. I believe that when it comes to rules of thumb for control joints, they rarely (if ever) need to more than half the thickness of a slab. There may be some rare cases ( I'd like to see documentation) where cutting or tooling half or more of the depth is required, but usually 1/5 to 1/4 of the slab depth is sufficient. It doesn't take much for the "weak link" principle to kick in. Control joints should also be placed mainly with respect to tensile reinforcment members, isolation joints (if any), and the anticipated geometeric centroid of each "controlled" material mass.
In my opinion, false blanket statements like the one quoted above doesn't contribute toward a working knowledge of concrete; certainly not on a professional building forum.
WHAT WHAT?
After perusing all the credible source from deadnuts's post, I find nothing to make me want to change my practices. I have much success CONTROLLING concrete cracking by CONTROLLING where it cracks. I do this by cutting CONTROL joints. Does it also crack other places? Sometimes. But with no CONTROL joints it will crack wherever "the forces of nature" dictates. In any case, somebody asked my opinion.
keep perusing
I don't have a problem with folk's stating thier opinions--even if they happen to be wrong. YOu know what they say about opinions...
However, what I will take issue with is someone that posts unqualified opinion masquerading as fact. MYBuilder made two such flase statements; both of which were not qualified as opinion (at least until I pointed out the discrepency in his assertions). There's no free pass on that "iin any case". I see that as constituting the dissemination of misinformation which doesn't help the uninformed in our trade. I will calll that out as unproductive every time I see it.
For the record, I couldn't care less if MYBuilder cuts his control joints more than halfway through his slabs. Heck, one is free to harbor the foolish opinion that cutting all the way through the slab achieves the same goal. Have fun with that.
It sounds like you have a problem with folks stating opinions
If someone wants to know the PCA way, they would go to the PCA site. There are hundreds of sources for every question asked on this forum. People come here because it's called Fine Homebuilding. They're hoping for four or five pros to give experienced knowledge. They could have asked a trade group, but the answers there would have either been too technical for a layman or too vague so as to avoid liability. Here, they might get 2, 5, 10 experiences to pull from. Cool! Take the best three shake em up and DIY til your heart is content. Most of us don't know each other. We don't need to. We know our business, what has worked what hasn't. We pass it on. If you have a tried solution, share it. You can't just call people "uninformed" with "foolish opinions". You can't tell from Washington what is wrong in Indiana. Pointing out "discrepencies" in peoples way of doing their job in an online forum isn't neccesary. People want those opinions. What they don't want to know is that you don't care how MYBuilder cuts his control joint. They certainly don't know I am foolish. They wouldn't have asked if they knew. "Have fun with that"? Why? What did that bring to Alaskahoan? He probably thinks we're both ten years old. The only reason I'm even following up is because this is the third time you've called me stupid in the last week. You don't even know me. "You know what they say about opinions..." Really? I thought deadnuts meant right on, like totally level or exactly 1/32". Perfect fit, exact, etc. I gues my opinion was wrong. Again.
You've been here over a year and typically posted every month or three. Now all of a sudden you're here all the time. One would guess that you've gone through some sort of "life transition". Want to tell us about it, rather than just ranting?
Thanks for the introduction, Dan
Actually, I've been a member for 12 years, 39 weeks. I used to have the user name wdbtchr. That was back when I was a wood butcher. Some how, after a period of absence, I could no longer login. I opened another account based on my company name, MYBUILDER. Interestingly enough, M and Y are my initials. Mike Yelton. In this .com age where everything online starts with my, it works out great! Business is good, the family is fine. I took off some time this year, hence the ability to post more frequently. We are going on a two month camping trip from Indiana to the west to hit as many national parks as time will allow. My wife and I feel it could bet he last time our 16 year old boy wants to do the family thing. I feel as though I have a good grip on life. It's nice to know you care. I hope you have similar good fortune. Thanks again. Sorry to Alaskahoan, we won't be taking the trip all the way North. I do hope to get there with the Mrs. soon though. Good luck to you too.