pex floor install tips

[stealman]

I am almost done with insulating my shop floor and will be installing the pex to the ridged foam with staples. I have never done this. I have a drawing of the tube layout. Can anyone provide any tips? I am wondering about marking the layout on the foam with paint or something before I start with the tubes? Is there anything I should be aware of as far as using the tube stapler? Also, how should I brace the tubes where they terminate? And the pressure test. I don't have a manifold yet and will joint all the pipes together and test with a gauge. How is the easiest, cheapest way to connect all the pipes? Any other words of advice would be great.
Thanks

 

[tdkkart]

Like a fool, I snapped chalk lines every 12" on my foam to use as a guide laying the pex, I looked like a smurf by the time I got the tubing down.
I bought a pressure test kit when I bought my tube, wasn't all that expensive for enough **** connectors and gauge to loop it all together. I think $35 or so??

Wrestling with a 1000ft roll of tubing isn't fun, but it obviously gets easier as you go.......... you could buy smaller rolls but you'd have a bunch of waste.

 

[Jackfre]

Take detailed photos of the finish lay out and VERY DETAILED MEASUREMENTS. Once the concrete is down you will want to punch holes in the floor for some reason or other.

On some jobs, depending upon who was doing the pour I used to put a few drops of oil of wintergreen in the tubing and pressurize the system. That way if some hammer-head cut the tubing everyone knew it and a repair could be done. Only happened once, but it saved a real problem. Be careful with your riser bends. Don't kink the tubing. Use the radius supports for the short radius 90* bends. Don't be in a rush. I used mesh on my jobs mostly so I would just loosely tie-wrap the tubing to the mesh. Nice and straight and easy 12"oc. I'd take a 2x2 with a 16p nail at the elevation I wanted the mesh/tubing and as the concrete was being poured I'd hook that nail under THE MESH between the tubes and bring it up to proper elevation. I prefer tubing in the center of the slab rather than under it. Don't put joints in the slab unless you have a leak on the pour. Tubing is cheap compared to the nightmare which can ensue. Oh, and once you are done and this winter when the floor is warm, don't forget to wear shoes when you work!

 

[Highbeam]

That is the beauty of steel mesh. When you lay the mesh down and properly align it you are left with a huge sheet of graphing paper style grid with 6" on center squares. Makes layout a dream since you can respect the 6" radius, do 6" OC near the edge, and 12" oc everywhere else. Rather than staple, I went through about a 1000 zip ties.

No problem. Oh and I used the 330 foot rolls of pex since my zones were designed to be under 330 and it worked great without me wrestling with a 1000 footer, that would have been awful.

 

[stealman]

Thanks everyone.
I have some more questions.

How much pex should extend above the slab at the manifold location?

How far should the tubes be from the toilet drain?

How far should the pex be from the front of the lower cabinets?

Pex under shower?
Under water heater?
In closets?
Under stairs?
How far from refrigerator?
Under wood burning stove?

 

[D.J.]

I'm no expert, but I would think it depends on wha`t type of shower you will have. If it is a grout and tile directly on the slab I think the answer would be to put it under the shower. But if it is the shower stall molded type fiberglass, I would think not to put it under the shower.

 

[Sea_J]

I used rebar and zip tied the tubing directly to it every sqare foot. I also went to MENARDS and they printed me out a way to lay out my pex based on garage demesions and were my water heater is loacted. Their drawing worked perfectly with my lay out. Also get all of the zip tie clippoings they will float to the surface in the concrete.

 

[BD1]

We use one of those wheel measuring devices. It will allow you to determine
the footage of each circuit and getting the most out of a roll. Invest in some
PVC electrical preformed 90's or bend your own in conduit. Slide these over the radiant tube where you are going have your headers. Mount to wall with unistrut and unistrut clamps. Makes a professional job and the tubing will be protected where they come out of slab. This is a real good way to protect them if machine trolled. Make sure you test before pour and leave test on during pouring too.

 

[rburke65]

So you guys that tie wrapped the pex to the mesh, your pex was on TOP of the mesh???

 

[Highbeam]

So you guys that tie wrapped the pex to the mesh, our pex was on TOP of the mesh???

Foam, then mesh, then zip tied pex to top of mesh. Cut zip tie tails off and collect them so that they don't stick up through the mud surface.

 

[BadgerBoilerMN]

We only tie to wire on commercial work or in the odd raised tube job. It takes 4 times longer to tie than to staple and zip ties make our fingers hurt!

We use 1000' rolls spun off an uncoiler, again, much faster and as suggested less waste. We often use PEX approved for space heating and DHW so waste is further diminished.

We CAD the layout, so the pattern, tube length and spacing are all done before we start.

Oh yes, when we CAD the drawing the heating and cooling loads are done as well, including design water temperature, flow rate, etc. etc.

I know that performing a heat load offends some people, but I don't know any better, as I started designing and installing radiant floors in 1987.

Your PEX vendor should be able to answer all of these questions, if he can't find one that can. Design help -tube layout and maybe even a "heat load"- is available from the best vendors and usually costs a few hundred, well spent dollars. If you buy all the materials direct, you should have some design help.

But life is a journey and sailors aren't made on calm seas, eh?

 

[Bigturk]

Here is a pic of my layout, 24 x 32 with wire mesh and 1/2 pex with O2 barrier.

 

[Fastback]

I would never staple the PEX to the foam, the closer the PEX is to the center of the slab the more efficient your heat exchange will be. The foam will not radiate the heat back up into the slab, and it will not convect heat if the PEX is sitting on it..

Studies have been done, feel free to google it.

 

[Highbeam]

Here is a pic of my layout, 24 x 32 with wire mesh and 1/2 pex with O2 barrier.

Yikes, be sure not to let the pex get so high that you cut it with the saw!

 

[BadgerBoilerMN]

There is simply no reason or benefit to suspending a tube in a typical 4" slab. The only benefits to a tube suspended in a slab (proper done with chairs) is improved response time and lower operating temperatures. Neither of these matter in the typical residential or light commercial jobs discussed here.

Flat wire has absolutely no value at the bottom of any slab - and pulling it up by hand is an invitation to disaster. We install snow melting systems here in Minnesota using PEX stapled to rigid insulation and wouldn't consider the extra cost and labor of tying PEX to flat wire for the typical snow melt and even less for space heating.

If you must use wire, place it on top of the PEX where it will do some good (crack control) and don't read too many books on the subject...they are not always right for every application.

Suspended tube is for high performance applications and generally are not used by professionals in a slab thinner than 6".

Before taking advice from the one job "experts" study carefully your "Google" search information.

 

[Fastback]

There is simply no reason or benefit to suspending a tube in a typical 4" slab. The only benefits to a tube suspended in a slab (proper done with chairs) is improved response time and lower operating temperatures. Neither of these matter in the typical residential or light commercial jobs discussed here.

Flat wire has absolutely no value at the bottom of any slab - and pulling it up by hand is an invitation to disaster. We install snow melting systems here in Minnesota using PEX stapled to rigid insulation and wouldn't consider the extra cost and labor of tying PEX to flat wire for the typical snow melt and even less for space heating.

If you must use wire, place it on top of the PEX where it will do some good (crack control) and don't read too many books on the subject...they are not always right for every application.

Suspended tube is for high performance applications and generally are not used by professionals in a slab thinner than 6".

Before taking advice from the one job "experts" study carefully your "Google" search information.

It's interesting how the laws of thermodynamics come into question around here.

How in the world can anyone benefit from the bottom portion of the tube sitting directly on a surface that neither convects or radiates the heat back into the slab. You are not even using the bottom portion of the tube for its intended task, and with a radius that adds up to a large amount of tube that's just going to waste.

You state that chairs are reserved for commercial systems, so why go cheap just because it's a 4" floor in a residential environment?

You clearly state that suspending the tube in the slab reduces response time and allows lower temps, both reduce load on the heating unit, so why would you recomend staples? Is it to save the few hundred dollars now so he can pay it later?

I will still tell people to get the tube off the foam so the entire tube can contribute to its intended task. You don't need to center in a 4" slab but at least get it up enough to allow the tube to be inside the slab.

And to the OP, before you take advice from guys that do this to make money, and use Internet forums as a soap box for marketing a business, do your own google research.

 

[matouse3]

I would never staple the PEX to the foam, the closer the PEX is to the center of the slab the more efficient your heat exchange will be. The foam will not radiate the heat back up into the slab, and it will not convect heat if the PEX is sitting on it..

Studies have been done, feel free to google it.

I have googled it and am having difficulty finding these scientific studies. If you have a second, could your provide a link?

 

[joes169]

It's interesting how the laws of thermodynamics come into question around here.

How in the world can anyone benefit from the bottom portion of the tube sitting directly on a surface that neither convects or radiates the heat back into the slab. You are not even using the bottom portion of the tube for its intended task, and with a radius that adds up to a large amount of tube that's just going to waste.

You state that chairs are reserved for commercial systems, so why go cheap just because it's a 4" floor in a residential environment?

You clearly state that suspending the tube in the slab reduces response time and allows lower temps, both reduce load on the heating unit, so why would you recomend staples? Is it to save the few hundred dollars now so he can pay it later?

I will still tell people to get the tube off the foam so the entire tube can contribute to its intended task. You don't need to center in a 4" slab but at least get it up enough to allow the tube to be inside the slab.

And to the OP, before you take advice from guys that do this to make money, and use Internet forums as a soap box for marketing a business, do your own google research.

I take it you've never actually witnessed what pex looks like in a finished concrete floor in real life? If you had seen a cross section, you'd know that the concrete does encase most (probably 95%) of the tube. When concrete is placed, it's typically "fluid" enough to work around the tubes and unless the staples are placed on 2" centers, the tubes have a tenancy to float up slightly.............

 

[BadgerBoilerMN]

OK Mr. Fast;

As Joes correctly points out; understanding the Laws of Thermodynamics don't do you much good unless you know how radiant floors are installed and function.

Tube placement is a matter of degree and cost/benefit. After a few hundred installations you find what pays dividends and what does not. For instance trashing someone for an opinion because he does it for a living, while choosing to ignore his professional advice...now there is a question.

Fortunately many do question the "free" advice given here and elsewhere, but truly I usually only get the rabid "you're not welcome here, you nasty capitalist" on the pure DIY sites, and tend to avoid for there generally ungrateful attitudes.

By all means, if people do their "research" and insist on wasting time and money suspending tube in thin residential slabs, it's a free country, as it is with all the advice I give on this forum. Giving advice on projects you have not seen, with limited experience to guide you, and advising people that every PEX tube must be in the middle, off the bottom, in the top 2" etc. etc. etc. is infinitely more suspect than offering professional design to the truly well informed. I have read all of Ziggy's books, use his software and have been attending his seminars since the 80's. Fortunately,suspending tube is a small part of the books and not the most important.

Let's match credentials, shall we? http://www.badgerboilerservice.com/experience.html

You know, I try to be nice.

 

[Highbeam]

OK Mr. Fast;

You know, I try to be nice.

Not trying very hard. If you were truly wise you would be able to pass on information in such a way as to earn respect. Instead you seem to want to bully folks with your opinion which takes away from your offering.

I honestly believe you have the knowledge, just lacking skills with packaging.

 

[rburke65]

Getting a little nasty here! Can't we all get along?

 

[50cal]

OK Mr. Fast;

As Joes correctly points out; understanding the Laws of Thermodynamics don't do you much good unless you know how radiant floors are installed and function.

Tube placement is a matter of degree and cost/benefit. After a few hundred installations you find what pays dividends and what does not. For instance trashing someone for an opinion because he does it for a living, while choosing to ignore his professional advice...now there is a question.

Fortunately many do question the "free" advice given here and elsewhere, but truly I usually only get the rabid "you're not welcome here, you nasty capitalist" on the pure DIY sites, and tend to avoid for there generally ungrateful attitudes.

By all means, if people do their "research" and insist on wasting time and money suspending tube in thin residential slabs, it's a free country, as it is with all the advice I give on this forum. Giving advice on projects you have not seen, with limited experience to guide you, and advising people that every PEX tube must be in the middle, off the bottom, in the top 2" etc. etc. etc. is infinitely more suspect than offering professional design to the truly well informed. I have read all of Ziggy's books, use his software and have been attending his seminars since the 80's. Fortunately,suspending tube is a small part of the books and not the most important.

Let's match credentials, shall we? http://www.badgerboilerservice.com/experience.html

You know, I try to be nice.

I have received great advice from this gentleman and my supplier in Nebraska.
Who gave me the best advice when I started to get to technical.
"This is not rocket science", that will be all.

 

[BadgerBoilerMN]

I like you too Highbeam;

I used to wrestle. You should not take it personally. Not everyone appreciates me...like my x-wife for instance .

I have made many claims here, being wise was never my assertion, though I could not agree with you more, both in your premise or your conclusion.

But, bully? I don't think the definition will stand up. If your facts are straight, you have nothing to "fear" from me. Debate can be a rough business and not for the light of heart.

I think I will take a rest though, and let the nice guys bend the laws of physics, unchallenged for a while. Have a nice summer.