Radiant Lines

Radiant Floors

In all cases where a Radiant Line enters into a room, it first runs along the outside wall, then goes to the center of the room preferably in a double serpentine pattern, then the return line goes back along the outside wall, exits the room and travels back to the Boiler.

• We are using 1/2" PEX for Radiant Systems, not for drinking use.
• The Radiant Lines are no more than 1' foot apart throughout the bulk of the living space.
• The Hot Entry Line is placed 3" from the outside wall and runs the perimeter of the room.
• The Cooled Exit Line is placed 3" to 4" inside from the Entering Line, then returns to the Boiler.
• We used the Double Serpentine Method as often as posible, where it wasn't possible we alternated between return line and entering line, or just filled a space with same temperature lines.

Master Bedroom


We began the radiant system in the Master Bedroom, we ran the hot line along the outside walls first, this will also hold true in all other rooms as well. After running the hot line along the outside walls, I heated the floor on Mary's side of the bed, then began a double serpentine run in the center of the room and usable space, then the return line went to heating under the bed and then returned to the Boiler. I figure why heat to a comfortable level an area that isnt lived in, under the bed will still be warm, but the usable space is the primary goal. It took two loops of 250 feet to complete the Master Bedroom. The green lines on the floor are where the walls are. The PEX will be low enough in the concrete to not have to worry about puncturing it with nails when we put up the walls. That and I have a very detailed drawing of where the PEX is in all of the rooms.


Secondary Bedroom #1


All the loops are 250 feet and you have to start counting those feet from the Heating System, so when a room is 60 feet from the Boiler, you have to count 120 feet just to get to the room and back to the boiler that is taken out of the square footage needed to heat the room. In our case both Secondary Bedrooms are 60 feet out, and have two loops heating them because we were using up so much wasted footage.

OK, it isn't wasted footage, we used the 120 feet from the lines to the bedrooms to heat the half of the Living Room, and the entire Laundryroom.


Secondary Bathroom


This is the Secondary Bathroom, it took only a 160 foot loop to heat, the bulk of the heat is in the center and left side of the room, then it goes to the right side, heating under the bathtub, and closet, then returns to the Boiler.

Reflective Insulations

I have recieved a few e-mails about our use of relective insulations, and chose to address them here in writing and in pictures.

We are using three types of reflective pruducts, each having the same 97% reflectivity.





R/B/B/R = Reflective/Bubble/Bubble/Reflective -



This is used in the attic space. Along the underside of the top truss, leaving a 4" to 5" air channel right below the roof sheathing. This channel runs from the eaves to the peak in an unbroken run. The reflective foil will work in several ways.

R/B/B/W = Reflective/Bubble/Bubble/White Poly -



This product is for use below a concrete slab floor. The manufacturer recommends using the material white poly side up so the concrete touches the white poly material instead of the concretes acidic qualities eating into the reflective surface, which would put the reflective surface at this point facing down.***

*** Here I find a problem, and here is where I walk a different path. I placed the reflective side up, why? Because HEAT is RADIATIVE, the reflective surface reflects 97% of radiated heat, since our slab will be using radiant heat, the slab will be hot, and the heat that radiates down from within this heated concrete will if it hits a highly reflective surface be reflected back up into the living spaces. COLD DOES NOT RADIATE. Why are they facing the reflective qualities of the material towards a source of energy that does not radiate, its not as if the cold will be bounced back into the earth. So I have turned the product upside-down, and put a sheet of 6mil clear plastic, taped at the seams, ontop of the reflective surface to keep the concretes acidic nature at bay. End of rant. For now.

R/K = Reflective/Kraft Paper -



This product has the same reflective qualities as the above products, it is just stuck to a sheet of kraft paper. This we used below the tar paper and shingles, and on the west wall behind the tyvek, to help radiate the setting sun's heat gathered in our west wall stucco.


Now that you know where I am coming from, here is where I am using the stuff and why.

R/B/B/R = Reflective/Bubble/Bubble/Reflective
Lets re-establish here the where and the why, this is used in the attic space. Along the underside of the top truss, leaving a 4" to 5" air channel right below the roof sheathing.



This channel runs from the eaves to the peak in an unbroken run. The reflective foil will work in several ways.

1. As a reflective membrane. As heat radiates through the roof sheathing it is bounced 97% back upwards. This reheats the sheathing and radiates back outside. It also heats the air within the 4" - 5" air channel.

2. As a wall for the air channel. As this heated air rises, as hot air does, it pulls cooler air in at the eaves. This funnels the heated air within the channel upwards to the peak where it vents outside. This keeps a cooler temperature in the air channel; in turn keeping the bubbles from gaining so much more heat.

3. As insulation. The bubble/bubble aspect of the material is individual packets of air bubbles, the same kind of bubble-wrap that no one can resist popping when it is used in shipping boxes. These air bubbles do not allow air movement through the material they only allow the heat within them to radiate through. And this radiating heat is already dimminished by the reflective membrane above it.

4. As reflective of internal heat during the winter months.






Now to explain things further:

This method of channeling the heat out from between the trusses isn't intended to entirely keep the attic from getting hot, it is intended to keep the attic from getting blisteringly hot. The attic will get warm, possibly even hot, but no hotter than the ambient air temp out side, and probably as seen so far, much, cooler though not so cool as to condence water. We will also need to keep the air mass in the attic dry, because moisture transports heat. A dry 75 is so much "cooler" than a humid 75.

The use of reflective membranes is for heat only, no matter how little heat we are talking about. It does not work reflecting cold, just lesser amounts heat. So during winter as the sun warms the roof, it will also heat the air in the channel same as during the summer, only less so. Here is where I am planning a new approach and walking a different path yet again. We are going to close the eave vents and thus trap the air in the channel, this will keep a heated mass of air in place, thus warming the bubbles and the air in the attic. When I say Heat, we are only talking a few tens of degrees in the air channel, less so in the attic space, but here is where #4 from above comes into play, by reflecting back into the attic environment any radiant heat making it through the airchannel, or radiating up from the living space below keeping the attic mild during the harshest of winter cold. At night the heat will replace with cold in the air channel, but the heat in the attic space will be bounced around within the attic at the same 97%, loosing 3% to the cold air channel. All this is to allow our heat system to run more efficiently by not loosing heat to a deeply cold environment in the attic. Heat flows towards cold. So if the attic isn't "cold" then the heat in the house wont migrate towards it. If all this is confusing, welcome to thermodynamics.





We may also need to go into how the heat system works in order to fully see how a house is functioning, and breathing.

1. In a conventional house, with 8 foot ceilings, and forced air heat.




There is a plume of heated air coming from the air ducts straight to the ceiling, where it heats the air up there; on the ceiling. The warm air fills the void of space along the ceiling and as it falls because its cooling, it comes into your living environment, (the chair, couch, dinning table, the bed) and continues falling to the floor colder and colder and returns to the duct system to start all over again. The ceilings are warmer than the living environment, and even cooler at the floor.

2. In a conventional house, with 8 foot ceilings, and radiant heat system.



The heat is pumped through the floor heating up whatever mass is there, whether that mass is a wood floor or a slab of concrete. This heat then radiates from the floor upwards throught the living environment first your feet are warmed then the chair, couch, dining table and bed, then on upwards to the ceiling, as it is a radiant heat objects warm up as well, so will the ceiling, the whole environment is evenly warm.

3. In a house with tall ceilings, ours at 12', and a radiant heat system.

Things change yet again, the environment up to about 8 feet, is warmed by the radiant heat just as in a conventional 8' ceiling home. But the environment above the 8 foot mark begins to layer itself, a mildly warm area, and a cooler area and then there is the ceiling, the coolest part of the room, this is what I have heard called "layering of the thermal zones." Kind of like a lazagna, the hottest part is at the bottom. There is so much more to write, but I am out of time for now. Be back soon.




I think that is a good start, Lets rest here until I have time to write more.

Re-Mesh

Re-Mesh




Here we are getting the grid of #10 re-mesh put down, the white of the floor is actually the reflective silver side of a product called R/B/B/W TekFoil, which stands for Reflective/Bubble/Bubble/White-Poly. On top of that is a layer of 6mil plastic taped at the seams, and then the welded-wire grid.


Now the sellers of the R/B/B/W says to put the White side up (corrosive preventor), and the Reflective side down, this runs with the thought that the cold in the ground would be reflected down, therefore keeping the heat in the concrete slab from being chilled from below allowing you to save energy by not loosing as much heat downwards. The White-Poly side keeps the product from being destroyed by the acidic concrete. And the Bubble/Bubble act as insulating barriers to the two sides.


Sadly this makes absolutely no sense what-so-ever to me, so I am once again doing things my way rather than the way I am "told" via the "instructions" and so I have placed the product Up-Side-Down... With the White side down and Reflective side up.


Here is why: We are heating the house with radiant pipes running through the slab of concrete.


1. Heat is Radiative, therefore the Reflective side will reflect the radiated heat back up into the slab, and then beyond up into the living environment. The Reflective side is 97% reflective of radiant energy, heat radiates, cold does not.


2. Cold is Not Radiative, it will not be "reflected back downwards by faceing the reflective surface towards the source of cold" i.e. the ground. Hence; in my book; it receives the white poly, which is just a vapor/sand/radon barrier at this point.


3. There are two layers of Bubble between the White-Poly side and the Reflective side to better insulate the heat from the cold. 3% of the heat from the slab which moved past the reflective surface, will move through the materials, heating the air in the bubbles, and diminishing the effects of the cold earth.


4. We also have a layer of 6mil clear plastic to handle the job of corrosive preventor from the etching and destructive powers of the acidic concrete protecting the highly reflective surface.





You can barely see our curious dog Riley, standing in the far doorway, she is a pretty good dog and stays outside most all the time now, we are trying not to let her nails pop all the bubbles. D'Artagnon is cooling off for abit playing with some cars on the floor.


The grids are rather flat, they don't look it because of the plastic sheets tugged this way and that. We have secured them altogether with zip-ties. We will attatch the radiant pipes to these grids pretty soon.


You can also see the sub-grade pipe (middle/top) that sits above the sand floor, it will still be 2" below the finish surface of the concrete, we still need to reinforce this area with sticks of heavy rebar so we dont get any cracks in the finished floor. (thanks Mr Joiner)

More to come soon.