retrofit over concrete

lvremodel

Our downstairs is concrete and we want to know the best product to install over the concrete without raising the floor too much.  House built in 70s and ceiling isn't too tall.  Downstairs consist of family/game room, 2 bedrooms and a bathroom.  Have hydronic system.  Should we install thermal panels or thermofin?  Do we put a moisture barrier down and then plywood or is there something else we can do.  Reading about these products and just confused.  

SWEI

Is this slab on grade?

If so, the lowest profile solution I have found is Roth Panel.

NRT_Rob

great product

for that application. I second Roth Panel. not cheap, but it is a great choice if your slab is not insulated already.

Mark Eatherton

Roth panel on the ceiling works fantastic as well...

And you could end up with less head space lost between the ceiling and floor.



ME

lvremodel

retrofit over concrete

Thanks, sounds good.  It may be insulated, but don't know for certain.  Did a test and no moisture, but it is concrete.  

lvremodel

retrofit over concrete

Interesting idea, always heard heat rises, so won't we have to run at a higher temp to get the room warm?  We live in Montana.  We are planning on putting a sound deadening insulation.  

SWEI

heat just moves towards cold

Hot air and hot water both rise, since they have lower densities than their cold counterparts.



Conduction is the issue inside the floor, and only R-value will do what you want.

NRT_Rob

radiant ceiling is great

but not over uninsulated slabs.

ThatGuy

Radiant walls?

Saw this on a job side one time where they could not get enough heat out of the floor, so they added supplemental heat to a couple of exterior walls. They added QuikTrak on the lower part of you walls (less than 4'), unless you never plan on hanging pictures; shoudl not effect you ceilign heights

Dave H_2

Radiant Walls

Is this basement a below grade basement? Without heat, does it maintain a decent temp all by itself (50-55F)?



My point is, I did a build up of my basement floor and added radiant. However, the one thing that you want from a radiant floor system is warm floors. I don't experience the warm floors much, the heat load is so low that the floor doesn't stay on too long in order to satisfy the heat call.



I have done a few radiant wall projects, but without panels. looped the tubing in the wall cavities and give it a couple of twists and staple to the sides of the studs so that the tubing crosses itself a few times. The tubing is "free-Flowing" so that any nails or screws put into the walls, the tubing will move out of the way.

Insulate behind, and yes even install on inside walls for ease of install.



Dave H.

Jean-David Beyer

I do not think it matters how long the heat is on.

"However, the one thing that you want from a radiant floor system is warm

floors. I don't experience the warm floors much, the heat load is so

low that the floor doesn't stay on too long in order to satisfy the heat

call."



My house here in New Jersey (design temperature: 14F) has low heat load too. I have outdoor reset so the supply temperature can be quite low to the radiant slab floor. It can be on as long as 18 hours a day, but the floor temperatures are very low until it gets down to about design temperature. Then the floors can get up to 80F. They are only then warm enough to notice (although my IR thermometer notices sooner). And it is better when stepping out of the shower onto the marble tile floor than if it were unheated. But even then, I would usually not call it warm.



I think this "warm floor" stuff is mostly advertizing hype. True, the floors are warmer than they would be if they were not heated.

Harvey Ramer

Your floors can be as warm as you want them to be.

All you have to do is loop zoning based on odr. Of course with proper loop placement.

Jean-David Beyer

Can you explain what you mean?

If I make my floor any hotter than my present reset curve specifies, I will get terrible overshoot, and they will not remain hot very long, since the present low temperatures of the floor (low 70s) supply enough heat. If I could change the floor temperature rapidly (impossible: concrete slab at grade), it would probably be hot for only a few minutes.



So how do you figure I could run that floor hotter without overheating the place? I would not wish to open the windows to increase the heat load.

Harvey Ramer

I don't care what house you reside in

There is a percentage of the floor where your feet normally reside and and a percent where your hardly ever trod. Take the former and zone it to be on all the time. Take the latter and zone it only to come on after the outdoor temp has dropped below a predetermined setpoint. It will require the heated area of your floor to run at a higher temp all the time.



Like i said before, If you want to do that loop placement is critical.

Gordy

Radiant floor temps

Radiant floors should feel neutral IF the dwelling has a decent envelope, and the system has proper controls. The only time you will notice a warm floor is when outside temps are extremely low for extended periods. Or iif the envelope is like a submarine with screen doors.



For the most part a basement is low load once the rfh has reached equilibrium.



Edit: Harvey does have a solution IF the warm floor sensation is desirable. Concentrate tubing in pathways traveled most of the time. Creating two zones with loops in non foot traffic areas.



The only problem is future movement of furniture. That's why I like the radiant ceilings. Save the floors for baths, and kitchens.





Gordy

Jean-David Beyer

OK: I will do that...

next time I replace the slab under my house. I will even make sure it is insulated underneath and around the edges.

Dave H_2

Basement Warm Floor

Yes, I could make my floors run "warm" all the time but that would have required making the boiler room more complicated. Design water temp was 104 while the rest of the house was 130 on a design day here on Long Island.

I did mixing reset, so that brought the water temps "closer" together and there are separate zones.

I could have added another mix, another circ.....I should have been clearer. Also adding the radiant floor to an existing basement added alot more cost compared to doing a radiant wall. Quik-Trak, added on top of a basement subfloor system, Dri-Core.



Dave H.