Need Advice On Radiant Heating in Ceiling

sashas

Hi,
I want to install radiant heating on the basement ceiling to heat the 1st floor. The thickness between the ceiling studs in the basement and the actual floor is 2 inches. I was recommended that would be better to use pex tube and heat transfer plates.

Do you have any recommendations about insulation? I measured space and there is about 5" left for insulation. I found Rockwool but it doesn't seem to have foil and as per my understanding foil is mandatory.

Please advise on what would work. or maybe there is a formula on how to calculate insulation thickness.

This is a picture on how it looks like to give an idea:



Thanks in advance.

Derheatmeister

Based on the pictures that you posted and due to the Fact that the tubing is not in direct contact with the floor the install does not look like a Professional Install...
One off the Benefits of the Aluminium heat transfer plates is that they will help transfer the heat via direct contact
By installing the transfer plates spaced off of the floor the heat transfer is pretty much non existing
Why even bother using Plates ?
I am guessing that answer is that you are going to run the temerature at 180 F

sashas

@Derheatmeister
The installation done by a plumber... I will ask him tomorrow why they not directly connected to the wood.

Is the temperature at 180F a bad sign? I don't know what would be a temperature but asking based on your emoji.

Based on what I understand if there will in insulation then these plates will heat some air and it will heat wood... I curious would it be enough to heat up 2 inches of floor coverage include the wood on the picture.

Maybe you can explain or advise something? I would appreciate

Derheatmeister

Air is a bad heat transfer medium ! ....In fact insulation works better because of the air intrained in it...
Here is a link for infomation/Reading material regarding proper heat transfer for Radiant infloor heat
https://radiantdesignandsupply.com/productsthermofin
This is a professional company that has developed the original heat transfer plates
They are located in Bozeman MT.
you may also check on Wirsbo/Uponor..Viega..Roth and Rehau for proper Installation recommendations /operating temperatures.

EdTheHeaterMan

There is more than one way to install radiant floor heat. Some are better than others. Based on what you have pictured Yo will want to create a sealed plenum for that tubing. The standard insulation job completed by an insulation contractor will leave air gaps at the edges, wall openings for wires, and the box plate at the end of each joist bay. This will allow the air in the 2" space to move out of the 2" plenum as the air temperature increases.

If however, you create a sealed chamber where there is no (or minimum) air leakage from the 2" plenum space between the floor joists, the heat will build up and keep warming the floor. The longer the air temperature below the floor and above the insulation is higher than the room temperature above it, the floor heat will be very efficient.

I would suggest that all the wire openings get caulked and all the rim and box joists get sealed with a vapor barrier and caulk. Once that is done then you might try a 2" foam board cut to fit then sealed with mastic or tape at each joint, seam, and connection. If wires are in the way of the insulation, then seal around them with mastic or caulk.

The job is not a complete disaster. You just need to finish it properly. The better you seal up the "PLENUM" the more efficient the system will work.

sashas

@EdTheHeaterMan
Thank you for the response and explanation.

I will follow your advice on how to do insulation and seal/caulk it to reduce air leakage downstairs.
In this case, may plates be left as is or they need to be in direct contact with the ceiling wood?

Thank you!

EdTheHeaterMan

They can stay as-is. If you take time to remove the spacers and get the plates to contact the floor, you will have Conduction Heat along with the convection heat. Then you may not be as exacting with the seal up of the "Plenum" design. The insulation can actually touch the subfloor and the tubing with no air space. Both are acceptable options.

Read up on the three ways heat travels. Conduction Convection and Radiation. If the plate is not in contact with the floor you don't get Conduction. you depend on convection. When you depend on convection, you don't want that heated air to go away thru the cracks.

When you have Conduction, then you can be less aggressive on sealing up the cracks. Do both for the best possible outcome.

Paul Pollets

The installation should have 2 rows of plates for each joist bay and the plates need direct contact with the subfloor. Any other method will compromise the performance and greatly reduce output. There needs to be R19 insulation over the plates prior to sheetrock.

STEVEusaPA

I doubt that will work at all. Have the plumber show you one picture off of the internet where piping/plates were installed/recommended by any manufacturer.
You're spending a lot of money on the install, now you have to double down with extra insulating and sealing, run 180° water, get no benefit of lower supply temps, have uneven floor heating...
--or fix it now and do it right.

psb75

I have never seen an install like in the photo. What was the thinking behind that? I'm surprised the spacer blocks did not split out. It will probably be less time putting the plates in contact with the floor than doing all the other remediating measures. But you still need to insulate R-19 underneath no matter what.

sashas

@psb75
Would this insulation work: https://www.homedepot.com/p/ROCKWOOL-R-15-ComfortBatt-Fire-Resistant-Stone-Wool-Insulation-Batt-15-in-x-47-in-RXCB351525/202090820 ?

sashas

@EdTheHeaterMan
Do you think the insulation per the link above will work? It has 3.5" thick. Maybe you can recommend another brand for insulation? I measured the can fit a maximum of 4-5" thick. The overall thickness is 6.5"

Thank you in advance

KC_Jones

I'm looking at the picture and I'm not even sure if those are the right plates for the application. If those are installed tight to the floor, the tubing will need to be installed first, actually I'm wondering how the install was done in the first place. The groove for the tube appears to be facing up, so that requires the tube to be installed from above, which is where the floor is. Those plates look like the type you would use above a floor, or revered and used behind drywall.

Am I missing something?

I agree with the above comments, if it works at all, it's probably going to cost an arm and a leg to run it, again if it even works at all.

psb75

I believe KC_Jones is right. Those plates are meant to go on top of a subfloor with 1/2" support on each side of the channel. The pipe gets pressed in and finished goes floor on top, fully in contact with the plates.

sashas

@psb75
The plates are from amazon: https://www.amazon.com/gp/product/B07SWZG874/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Is there a difference for subfloor plates and ceiling plates?

psb75

The best ceiling plates, like Uponor JoistTrak get attached to the basement ceiling and the pipe snaps in after that. These are heavier, more rigid, extruded, aluminum plates. It looks like your installer used "topside" u-channel, or "omega" thin-gauged aluminum in the wrong application.
If you could take the spacer blocks out, leaving the pipe in the channels, and re-attach the plates to be IN CONTACT with the basement ceiling/subfoor above....that would work well. And insulate underneath, between the joists.

JUGHNE

The spacer blocks were probably installed because of protruding nails from above.
The nails can be cut or ground off. With these plates there still is the possibility of nail stubs scratching on the tubing and with high temps the tubing (not soft) will be moving with every heat up and cool down.

The better plates that PSB75 mentions are preferred and protect the tubing from any remains of ground off nails.

180 degrees is probably at the top end max temp for the tubing and not recommended for constant operation.
Everyone else puts 2 plates/tubes per joist space.
Does your tubing have O2 barrier?
What type of boiler do you have?

At lot of time and materials that may turn to Sh!t in a few years. IMO

hot_rod

Was a heat load and design done on the rooms to see if radiant is even viable? That should be the first step before deciding on an installation method.

sashas

@JUGHNE
Not sure about the O2 barrier. How can I check? Currently, there is no boiler but I was thinking about Navien NCB-190 which will work better.

@hot_rod
I don't think so. I know that we measured the distance of the floor from the basement ceiling to the 1st floor it was 2 inches.

JUGHNE

The tubing should have info printed on it. Or the box it came in.
Just even the brand name......someone here knows a lot more about tubing specs than I do.

How is the room heated now?
Do you plan on this tubing to be the only source of heat for the room?

Hot Rod is referring to the actual heat loss of the room you are trying to heat.
This involved the area, wall & ceiling insulation, type of windows and air leakage.

hcpatel78

sashas said:

@Derheatmeister
The installation done by a plumber... I will ask him tomorrow why they not directly connected to the wood.

Is the temperature at 180F a bad sign? I don't know what would be a temperature but asking based on your emoji.

Based on what I understand if there will in insulation then these plates will heat some air and it will heat wood... I curious would it be enough to heat up 2 inches of floor coverage include the wood on the picture.

Maybe you can explain or advise something? I would appreciate

sashas

@JUGHNE
The boiler itself not installed yet. But yes it will be the only source of heat for the 1st floor.

@hcpatel78
Thank you

EdTheHeaterMan

I believe the best insulation to create a sealed plenum barrier would be 2" rigid foam board.
https://www.homedepot.com/p/RMAX-Pro-Select-R-Matte-Plus-3-2-in-x-4-ft-x-8-ft-R-13-1-Foam-Insulation-Board-637898/313501510

The Rockwool will allow for some air to migrate, there is no vapor barrier.

You mentioned that a professional installed the tubing and the plates. Does the professional have a plan of action? Did the professional complete a manual J calculation to see what size tubing, how much tubing, and what size heating system is needed to properly heat your home? Since the floor will be your radiator, you need to know if the floor is a large enough radiator to properly heat the space.

I see that there is only one tube per joist bay, it appears that a 1/2" tube every 16" may not be sufficient, but it may be. It all is in the mathematics of Thermodynamics. Do you have the design information or did your professional just guess?

I hope you did not pay in full for the job yet?

You may not be satisfied next winter when it gets really cold and you can only get the home up to 58°F

To be clear. Your picture does not show the tubing. I assume the tubing is already installed above the aluminum plates. I also assume that you are attempting the heat the room above the floor. If you do not have insulation then you will be heating the room below the ceiling. The floor will be the insulation so more heat will go down and less heat will go up.

Alan (California Radiant) Forbes

Seeing as though you already have one run per joist bay, the easiest way to get it right may be to use a product called Ultra-Fin. You would have to abandon all the plates, but leave the PEX.

You still need heat loss calculations and properly installed insulation. However, you might need a minimum of 2" x 8" joists depending on your climate and whether or not the crawlspace or basement is enclosed. If you only have 2" x 6" joists, there may not be enough room for the proper insulation.


http://www.ultra-fin.com/

sashas

Hi @EdTheHeaterMan

Thanks for getting back to me. I really appreciate it. After all answers, I hope that what has been done will work because I paid in full already.
The answer above from @Alan (California Radiant) Forbes also says that there might be a wood gap of about 2-3" between aluminum plate and ceiling, same says at the Ultra-Fin website, and the gap between wood and ceiling I have is 3 inches.

I trying to heat the room above and the tubing already installed is a 1/2" PEX tube above aluminum plates. The picture is from the basement which is closed and also will be heated.
The distance between tubes and plates about 17 inches. The overall floor is about 640 sq. ft. Each plate has a 4ft length and the distance between plates about 5.5 inches. The depth of the floor is 2 inches.

Regarding the professional who installed it:
He said that it should be enough heat and water temperature will be 100°F. I did not ask him to show me calculations but he told me that there should be a boiler with a specific BTU to be enough for all heat zones. The boiler (Navien) installation will be in the future later this year. He installed tubes the same way overall 640sq ft area with the distance between them about 17 inches. It looks like that he knew what he was doing and had calculations in mind. But after I saw it done and saw responses here I doubt what to do now. lease it as is or pay again to redo it...

Is there a way I can calculate that there will be enough heat for the upper floor? Can you advise formula that I can measure all and do math?

Thank you for the insulation advice. I can see that Rmax is out of stock in homedepot, can I choose another brand that will be vapor retardant, 2-inch thickness and R-23 rating or I should look for this brand?
I want to put 1-2" additional soundproof insulation, should it go before Rmax or after it?

As per my understanding after the aluminum plate there will be a 2" gap then Rmax insulation then 1-2" soundproof insulation. Is it the correct order?

For sure I will make sure that all connections/cracks are sealed with mastic or caulk.

Derheatmeister

Sorry it took me so long to get back...
Looks like eveybody is giving you good advise including some nice pictures of how a professional install should look like.

Please keep in mind the the Ultra fin product requires High temperatures such as 180F ! (Keep this in mind as i will explain later why this is relevant)

With your primary tubing spacing @ 16 ", An Airgap from the Plates to the subfloor of approx. 1 1/4" ,The floor being 2" thick and you "Design" temperatur @ 100F your Residency better be Located in a warmer climate such as the south (Florida).

As JUGHNE questioned before...Does your tubing have O2 barrier ? Check it to make sure it does ,as it is very relevant !

As to boiler selection.. High Efficiencys.. Nice.
Was this recommened by an professional that will help and support you when you need it?

Was the Size based on the Heat Load also in respect of the Turn down ratio?
Or is it based on Price with all the "Bells and Whistles" (Amazon)..

Just keep in mind that even the "Best","App enabled",Modulating Condensing Boiler will only perform "efficient"(90 Plus %) during low temperature operations such as below 138F...
I do not think you are going to get a "Bang for your Buck" on this selection since the"Plumber" will have to crank the Supply temperatures up.

This is something that gets even missed by many Professionals all of the time...So ,Pay Attention:

By operating this equipment at higher temperatures (So that it can overcome the lack of heat transfer and >>>TRY<<< to give you a comfort level upstairs) The Equipment will not go into an "High Efficiency" Condensing mode !
Condensing modes allow the Heat exchanger to "Take a Shower"/Clean it's self by using the Condensate to rinse the HX (Heat exchanger).
By not allowing the Boiler to "Take a Shower" it will allow for Combustion Deposits to form on the HX (Heat exchanger) which will further yet reduce the Efficiency and will require removal of deposits that will form on the HX....Generally this requires using Chemicals😒(Bad for the enviroment)
All this equation leads to Service calls which will cost money,which will Increase the overall life time span operating cost and your carbon foot print.
In my opinion the only thing that you are reducing is you ROI
Hope this helps..
Respectfully submitted.

Alan (California Radiant) Forbes

Please keep in mind the the Ultra fin product requires High temperatures such as 180F ! (Keep this in mind as i will explain later why this is relevant).

We never have to run our Ultra-Fin jobs that hot.

Heat loss calculations are key. As you can see, you can get 27 BTU's per square foot at a 150F water temperature. With a 20 degree delta, your boiler will be condensing.


@sashas Your first order of business is to do your heat loss calculations, room-by-room. Here is a handy tool. The final figure you come up with will give you a BTU per square foot amount and this is key. It will guide you to what product to use and the water temperature required on a design day (the coldest average temperature in your area).

As @Derheatmeister said, unless you live in South Florida, the suspended plates you have there will keep you shivering. Plates are intended to heat by conduction with direct contact with the tubing and the floor. The plates will surely get hot, but will hold the heat as they can't transfer it to anything other than air which is an insulator.

Derheatmeister

Alan (California Radiant) Forbes said:

Please keep in mind the the Ultra fin product requires High temperatures such as 180F ! (Keep this in mind as i will explain later why this is relevant).

We never have to run our Ultra-Fin jobs that hot.

Heat loss calculations are key. As you can see, you can get 27 BTU's per square foot at a 150F water temperature. With a 20 degree delta, your boiler will be condensing.

Alan.. Thank you for submitting this information on the Fins
I talked to the fin people at differnt Trade Shows and they allways told me that they like High temps..
There may be a Place for the Fins but we never found a Application for it !
Call us Radiant snobs ... We only Install infloor via
1. In Thin slabs or concrete (this is the Best)
2. Plated Staple up when the situation calls for it due to priceless existing floors
3. We prefer an easier,faster and more effiencent approach using a flooring system from above (Viega Clima panel) over the Stable up Plates.( This may have also been a opion for sashas especially if he is planning on replacing the floors upstairs?)
4. Radiant Ceilings or walls.
5. And Radiant panels..

sashas...As HotRod has mentioned above someone should have should have performed a Heatloos Calc. for this house...
We have no idea if you live in a Loose Log Home with very high ceilings and bad windows,or an Award Winning Greenstar Rated/Leed certified, heat your home via a candle type Haus..
We also do not Know if you are located in Florida or the North Pole.
It should all start with a Plan vs. "Shooting from the hips".

Alan (California Radiant) Forbes

@Derheatmeister I have the same lineup as you and used to order plates in bulk, but discovered that Ultra-Fin has distinct advantages.
1) One run per bay is huge!
2) Ultra-Fin is easy to install and does not require special tools for securing plates.
3) Plate manufacturers recommend water temperatures below 120F, above which hardwood will react. There are times when you need higher temperatures and Ultra-Fin, since it's not in direct contact with the floor, can accommodate.

sashas

@Derheatmeister @Alan (California Radiant) Forbes
Thank you for the reply. I will the tool which calculates heat loss. I live in Brooklyn, NY This is an example:

EdTheHeaterMan

I wanted to post my PM message for others to comment.

To be clear... If you want the heat in the basement ceiling to add warmth to the room above it, you should say "Radiant Floor Heat" If you want to add warmth to the basement with the same tubing, you should say "Radiant Ceiling Heat". By your description, I believe you are installing Radiant Floor Heat.

With that assumption here is a diagram that will illustrate my idea.

This design has been published but is not widely used. It is not recommended mostly because the heat will leak out of the plenum area in many cases. This is why you must be very careful to seal any openings like those illustrated on the left side of the diagram. You can see that the high-temperature water will build up enough heat if properly sealed as in the center section and the right section. In the left section, the heat can travel thru the holes and gaps in the plenum and dissipate in the wall by natural convection flow. (Those temperature measurements are for illustration purpose only your actual temperatures may vary)

The most neglected sections are those near the outside walls of the house. The rim Joist will need to be insulated on the outside surfaces of the home and the neighbor's party walls as illustrated here.

2" foam insulation can be any brand and it can have a reflective face or it does not need to have a reflective face.

The 2" space is not a critical measurement. The insulation can touch the tubing/plates or it can be a greater air space. As you can see in my illustration, the plenum can be any measurement as long as there is an air-tight seal in the plenum area. Do not sheetrock the basement ceiling until you are satisfied with the result.