How bad off am I?

[Ford GP]

I had radiant installed in my basement floor five years ago when we poured over the dirt floor of our old house. We were very height limited and had to excavate six inches of dirt out of the basement of our 130 year old house. We just didn't have the ability to go deeper as we were already at the level where the stone walls end (pseudo footer).
I got poor advice from the heating engineer, I trusted him (idiot). He recommended we use the bubble foil bubble insulation under the slab, and I applied corrugated plastic along the wall to allow any residual moisture off the walls to have a path to the french drain we installed along the perimeter of the wall. I did not do this along the interior walls and wasn't thinking about thermal loss. He should have been though Now after reading posts here (and others) I learned how little he actually helped, and really hurt my project, and how the foil does little to nothing. My question would be how bad off am I now that the concrete is poured? It makes me want to just cut the tubes and pretend it never happened...

 

[Fastback]

First off, insulating under a slab is not always preferred or always done. In a basement a floor is already on top of soil that stays above 50 degrees due to its depth, so don't get overly excited.

 

[KPSquared]

No one here insulates at all and most of the guys think the bubble foil is just fine. So, you may not be doing much good, but at least you're not alone.

I asked every contractor I could talk to about under-slab insulation and they all just stared at me like I was an idiot. . . go figure, we hit -40 here every winter and no one cares or knows about proper insulation.

 

[Chaz]

You'll be fine.... You dont say where you live, and that is a factor . Bubble insulation IS insulation and... well... heat rises.

 

[Fastback]

Heat does not rise, hot air rises.


Look at it this way, the roll foil is great for stopping radon and other gasses from coming through the slab!

 

[Ford GP]

Thanks guys, I am just North of Columbus, OH. Its funny how you get really good at something after you have done it and made all the mistakes. This website is one of the best I have come across about garages, and just guy stuff in general. I am in awe at the level of knowledge here...

 

[Kevin54]

Another Buckeye. Welcome. I'm just west of you a short ways in Urbana.

 

[lutter94]

Heat does not rise, hot air rises.


Look at it this way, the roll foil is great for stopping radon and other gasses from coming through the slab!

Fluids become more dense as temperature decreases. So hot water rises too....

Heat in a solid will travel the direction of least resistance. But liquids or gases, the heat will rise.

 

[Fastback]

Did you use any type of expansion material where the floor meets the wall?

If not your biggest worry should be heat crawling up the exterior walls due to the lack of expansion material or a thermal break between the floor and the walls..

 

[Rhsty]

Heat does not rise,heat goes to cold it takes air like was said already for heat to rise.Its like taking your porcelain coffee mug full of piping hot coffee and holding your hand directly over it of course its going to be hot,but try to hold your hand around it without using the handle that is the difference between convection and radiant heat. Radiant heats objects and convection heats the area. I put 2 inch foam blue board under all slab radiant jobs,My personal garage has it and the first 6 inches Of sidewalk outside during winter snow and rain is usually dry at the beginning of any precipitation for a period of time. So even with good insulation you still lose a little.

 

[Fun pain]

Near Mansfield, Ohio (Crestline)

I am an Electro-Mec Engineer

Heat goes to Cold.... first and foremost

yes hot (less dense air) rises (above cool more dense air)

I like the mug theory but it involves pressure which changes the concepts involved and pressure increases heat transfer in the same time interval. holding the mug you have increased pressure(weight of the fluid/mug) and used conduction/radiant. And throwing in "resistance" a miss leader... the only thing in this enviroment (basement) with less resistance is the foil. Air is a insulator and a "resistance" media. So we should refrain from using that on a web forum, just to hard to convay the type of resistance we are talking about.

The thermal break is a good post and goes along what I am going to ask.

Are the basement walls insulated and how are they insulated?

It is moot to have R-10 XPS under the floor slab if the walls are wet and uninsulated... that is a much bigger heat lose.

Walls of the house shoot for +r25, walls of subgrade (basement) shoot for +r15, and if you have that ,then worry about underslab. +r10.... r10 underslab and wet uninsulated brick/block/concrete for walls is not usefull and probably wouldn't help the energy bill much at all.

 

[Dragster Racer]

Fluids become more dense as temperature decreases. So hot water rises too....

Heat in a solid will travel the direction of least resistance. But liquids or gases, the heat will rise.

The heat, as stated, will migrate towards the coolest area. If that is the 50 degree dirt, then more will go that direction until the local dirt is warmed up. You will lose some heat to the ground. It's hard to tell how much really. Like was said also, insulating under the coils was not popular until recently.

 

[hondaman263]

^ This sure is a heated argument!!

Okay I had to do it...

 

[Highbeam]

Many of us are engineers, doesn't mean we're smarter. I agree with the statement that hot air rises, but heat travels by other means as well. I am often warmed by the sun and also by touching the bottom of my woodstove.

 

[Fun pain]

^^^^

 

[Fun pain]

^^^^ Yes I am not saying I am smarter and I didn't think we were debating. This type of Physics are laws and rules, that all Engineers are taught. (physics/math/thermal dynamics/thermal conductivity). These concepts were solved, many many years ago. And not by us. (Engineers)

Thermodynamic equilibrium
Internal energy of a system
Temperature and Entropy
Zeroth law of thermodynamics

This topic has just been hard for everyone to KNOW these concepts

He ask "How bad off am I?"

Well it depends on your basement walls and house walls really. If we are talking about energy conservation.