Reflective foil good for under concrete floor heat

colleenp

We recently had someone build a large building for us with floor heat under the concrete. We had requested 1 1/2 in tp 2 inch styrofoam under the pipes. They installed a thin foil/bubble wrap type insulation. Will that give us the same R value? Or will our building be very costly to heat?

RobG

No, that stuff is garbage. Try to get your money back. Yes it will cost you more to heat.

Zman

That is completely unacceptable. I would seriously make them jack hammer it up and do it over. The lies behind that stuff were exposed 10-15 years ago. It was banned by our local building department 10 years ago. Google John Seigenthaler Bad Science for a good read.
Also check out this link.
http://www.healthyheating.com/Page 55/Page_55_o_bldg_sys.htm#.VfnO6Jf538A

Ironman

Definitely not gonna do the job.

Can you give us some other pertinent info:
1. Is there any edge insulation?
2. What the square footage of the slab?
3. Was a proper heat loss calc done? If so, what is the loss?
4. How many feet of tubing are in the slab? What's the on center distance between the rows and what is the pipe diameter?
5. How many loops are there? How long are they?
6. What's controlling the water temp?
7. Any floor coverings?
8. What type of use is the building?
9. What's heating the water? Its capacity in btus?
10. Can you post some pics?

If you can supply the info, you'll get the right answers here.

hot_rod

It drives me crazy whenI see well know reps and wholesalers still offering bubble foil or thin foam products. What is the application where these products are acceptable?

That compromise of insulation will cost you for the life of that system, and future owners. You should get exactly what you asked and paid for.

rick in Alaska

Contact Mark Eatherton of the RPA. He did a study a while back with various insulations under a slab and has results for it.
That way you can show your contractor how bad it is and why they have to remove it.
Rick

Rich_49

Not the right stuff . You were absolutely right to request Foam in the thicknesses you state . If you have ground water within 6 feet of the bottom of that slab you are in more serious trouble from a heat loss / output perspective .

colleenp

Ironman -
1. Yes, there is an edge insulation - 2 " styrofoam.
2. 3,960 square feet.
3. There was NOT a proper heat loss calc done.
4. Pipe diameter is 5/8", on center distance is 24", 1,728 feet of tubing.
5. There are 7 loops in the floor and 2 in the footings.
6. Thermostat controls the water temp.
7. NO floor coverings.
8. Use of the building - one mechanic bay and two welding bays.
9. Propane is used to heat the water.
10. Photos attached

The other problem is how the piping had to be attached to the rebar on top of the foil. The plumber was expecting styrofoam to staple the tubing to. When the concrete was poured, a small powered hopper drove over plywood that had been laid out, one section at a time, on top of what you see in the first two photos. The results of that are shown in the third photo and there is now 1 complete loop that nothing can get through and 1/2 loop that is limited. This testing was done by the plumber. Needless to say, we are extremely frustrated.

Zman

Am I seeing it right? Did they kink the tube?
Arg,

Bob Bona_4

I'm seeing those nasty kinks too, who knows how many more exist. I wouldn't dream of 24" OC spacing unless it was a warehouse...what a shame. Do-over!

Ironman

That is an abomination! There's so much wrong that's been done by both the heating and the concrete contractor that both of them should be held liable for having the entire floor done over. Let me list a few things:
1. The concrete guy should have NEVER used a Georgia buggy over radiant tubing. That's 1980's methodology. A pumper truck should have been used. Kinking the tubing is totally on him and no one else. There was a long discussion on here about a year ago where this happened. I'll try and find it and attach a link.
2. A proper heat loss calc is the FIRST and most IMPORTANT step in designing any heating system - especially a radiant floor. That slab is only gonna give off so many buts. How do you know if it will be enough if an accurate heat loss calc wasn't done? This one, and all of the following are squarely upon the radiant contractor.
3. Once the heat loss is calculated, then the design of the radiant system must be done according to proper engineering formulas and practices. All of the pros on here use computer programs and/or hand written methods to achieve this. If a contractor is not capable of doing this, he should hire someone who is and follow his design to the letter or not be doing the job at all. There is no "one size fits all" way of doing this. All of the major manufactures of radiant tubing have design software or services available to do this and many offer training classes. There's no excuse for not designing properly, and again, the responsibility lies solely upon the radiant contractor.
4. As already mentioned, the 24" OC spacing is too much. I would not have gone over 16" OC using 5/8" tubing, probably less.
5. Not knowing your actual heat loss or your locale, I'm gonna take a very average guesstimate that IF your actual heat loss was 25 buts per sq. foot, then you would need 100k buts to heat the structure on the coldest day of the year. Unless you raise the water temp obnoxiously high, that floor is not gonna produce anywhere near that. If you do that, then you're gonna have "striping" which means the floor surface will be too hot where there's tubing below and too cold where there's not. With the lack of proper insulation below the slab, that will make the system very inefficient and costly to operate. That leads to the next point:
6. There should have been a minimum of 2" styrofoam board under the slab and the federal energy code requires 3".
7. For the life of me, I don't know why anyone would put tubing in the footers. They are in direct contact with the soil and that's where the heat from them is going. It also presents a freezing hazard for the tubing unless antifreeze is used. These loops should be abandoned.
8. A slab is high mass which means it takes several hours to bring it up to temp and that it will continue to give off heat for several hours after the heat source to it is shut off. It's called the "flywheel effect". Because of this, a thermostat is not gonna control the room temp properly. Your need a "smart" device that will vary the water temp to match the load. This is known as out door reset. There are three basic methods that it can be accomplished: with a mod/con boiler and the slab as its only zone; with a smart mixing valve; or with variable speed injection mixing. You did not state your heating source, so unless it's a mod/con boiler, you don't have the proper control. Still, the ODR curve of the device must be properly calculated and set up.

We can't give legal advice, but if it were my building, I'd be making those two contractors pay to do it over. And I would not let them be the ones to do it.

Attached are pics of the best method for in slab. The Crete panels provide the insulation, vapor barrier and means to hold the tubing in place.

Here's the link to the earlier thread:

http://forum.heatinghelp.com/discussion/154112/total-failure-on-all-pex-lines-in-new-construction/p1

Tinman

If that were my home, they'd be busting up the concrete today. The lack of workmanship and a sound plan is an embarrassment.
And the only one who is going to pay for that is you.
Make them do the right thing.

Gordy

This is how Radiant heating gets a bad reputation. Idiots try to install it. Its a science. Most people think you just throw a bunch of tubing in concrete, and your done.

I hope you did not pay for that in full.

The plumber who put the tubing down should have refused until proper insulation was done. And a heatloss, and a proper procedure to pour with out damaging the tubing. sounds like multiple parties had their hand in that mess.

Ironman

This is why I'm in total agreement with the RPA that proper training, certification and licensing should be required for radiant installers.

colleenp

All of these comments are so helpful in our battle. And I think it will be just that - a battle. We don't know exactly what course of action we can take to make this right. I think an attorney who has dealt with this kind of a situation would be helpful to talk to.

rick in Alaska

The tubing is definitely crushed in the one picture, and is not going to work. At least not with a huge pump.
With that rebar laying on the foil, it is not doing much good anyway. It should have been pulled up, but no-one does. Bring that up also when you talk to the concrete guys.
Rick

RobG

Try talking to the people to avoid bringing in the lawyers as it will cost YOU money (unless you're a lawyer). Hopefully the slab and insulation can be replaced relatively easily. What a shame, I wish that you had come here before you started your project.

hot_rod

It looks tall, maybe a new slab poured over the top, 2" foam, 12- 16" tube spacing. With all that rebar you have a fairly structural slab, if the base below is solid.
The overpower may not need any reinforcement other that a strong, fiber mix.

Rich_49

Where are you located Coleen ? Maybe we know someone near you

JUGHNE

Hot Rod, I was thinking about a overpour also. Any overhead doors would have to have the track raised 6" at the ceiling, not always possible. Walk doors headers moved up 6" also. Windows would seem and be lower. Electrical outlets probably have to be minimum of 18" off finish floor for repair shop. May or not be an issue. WC flanges could be extended with minor grief. Shop floor trench drain, if any, could be challenging. Step up into any office area maybe?

It does look like a good rebar job though. Are we looking at heavy truck repair?

colleenp

We are located in northern MN on the Canadian border. We make snow plows in the welding shop and work on nothing larger in the mechanic shop than a 1-ton pickup. We did not know this forum existed until we ran into so many problems and I began searching for info on the foil. We are not in the business to know how to build a building so relyed on the contractor to do the job we wanted. There were other issues but the heat is the main one.

hot_rod

JUGHNE said:

Hot Rod, I was thinking about a overpour also. Any overhead doors would have to have the track raised 6" at the ceiling, not always possible. Walk doors headers moved up 6" also. Windows would seem and be lower. Electrical outlets probably have to be minimum of 18" off finish floor for repair shop. May or not be an issue. WC flanges could be extended with minor grief. Shop floor trench drain, if any, could be challenging. Step up into any office area maybe?

It does look like a good rebar job though. Are we looking at heavy truck repair?

\I'll bet if you find a knowledgable concrete guy and redi-mix plant you could get a 3-1/2 or 4" overpower. There are many additives that can be added to "soup up" the mix, higher psi, plastic or steel fibers, smaller aggregate, etc.

Around here some finishers notch the overhead doors into the slab to keep driving rain out. Typically only 2" but a steeper ramp would allow a deeper notch.

all the others issues would still be less than a demo with all that rebar in it. It's best to demo concrete the next day or ASAP, after a few weeks it becomes "as hard as concrete"

SWEI

colleenp said:

We are located in northern MN on the Canadian border.

In that location, and given that you're burning LPG, you are talking about thousands of dollars per year -- forever-- to heat the space with that shoddy job. You've gotten very good advice above.

Best of luck and please let us know how things work out.

JUGHNE

Was the edge insulation on the outside of the footings or inside?
And how far down does the insulation extend.
The whole system would probably be glycol fluid.
The 6" lift was 4" concrete on top of 2" insulation.

Serious cold is not far away at that location.
(Even that 2" insulation sounds thin up there)

Gordy

The most cost effective solution may be radiant ceiling, or infra red radiant ceiling heaters. Maybe all parties would be willing to split their mistakes. The contractor will fight to the end before ripping out that slab. An over pour is less than desirable from the original detail done correctly.

Paul Pollets

What a scam. So much incompetence and hack masters out there. Apple Valley is not that far for training. Unless there's proper R10 insulation and perimeter insulation, not to mention tubing on correct centers, this project is doomed to minimal comfort, striping and high fuel costs.

colleenp

I will keep you all posted. Thanks for the input.

SWEI

No chairs on the rebar either from what I can see. Bar at the boom of the pour won't do much. Concrete guy failed even without considering the tubing debacle.

colleenp

Would it be possible for someone to post a link to commercial heating codes for Minnesota that would pertain to our situation? That would be extremely helpful.

DanHolohan

It pays to wander off the Wall: https://heatinghelp.com/systems-help-center/bubble-foil-insulation/

Ironman

DanHolohan said:

It pays to wander off the Wall: https://heatinghelp.com/systems-help-center/bubble-foil-insulation/

Dan,
The link comes up blank. I tried it with two different devices with different browsers.

SWEI

Leads to http://www.healthyheating.com/Page 55/Page_55_o_bldg_sys.htm