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Radiant Floor Heating/"Dry" sub-floor radiant heating system


Hi Mr. Audetetat,

I wish to install 1/2" pex to heat the main floor using a Dry Below System using a Double Loop of Pex installed between 16" O.C. Joists beneath the 3/4" fir subfloor which is beneath 3/4"  Fir flooring. I also wish to use heating plates that are .016" x 4' x 5". The hydronic heat source is a IBC SL20-115 condensing boiler with an outdoor sensor made here in Vancouver. My question is:  How do I install the plates and Pex to minimize noise? Specifically please recommend what type of straps I should use for the pex and where and how they should be placed and what type of heat transfer plates to use and how to install them. I can also get the plates in 2' lengths.  Appreciate your help. Thanks.

Badger Boiler Sub-floor panels
Badger Boiler Sub-floo  
In our day-to-day design/build radiant heating business, here in Minneapolis, the bulk of our work is in renovation and additions to older homes. More often than not, we are called out to consult on systems lacking performance. Once a room-by-room heat load is performed we proceed to specify the remedy.

In this market, and we know of many others around N.America, what passes for radiant heating does not do it justice. Many times we find a brand new, old-style, "staple-up" system, which will not satisfy the heat loads in the coldest weather and/or operates beyond the optimum design water temperature for the heat source or finished floors specified.

For these reasons and many others, we use a heavy extruded aluminum plate in all of our design work. There several sub-floor panels available but only one that performs to our satisfaction with the lowest noise and highest output; ThermoFin C tested is 4" wide , .0625" thick and extruded from 6063-T5 alloy.

The installation techniques and tubing specification are something we articulate in a radiant floor heating design consultation.

Radiant Floor Heating

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Morgan M. Audetat


Radiant panel heating design, including floors and ceilings, European wall panels and snow melting for residential and light commercial buildings..............................................................-Master of Steam and Hot Water,City of Minneapolis....................................................--- Master Plumber, State of Minnesota...........


30 years..... Charter Board Member - Radiant Panel Association, former manufacturer of condensing boilers, former national distributor of radiant floor products, son and apprentice of mechanical & plumbing contractor. Current mechanical/plumbing contractor specializing in hydronic based, integrated HVAC systems. Radiant floor heating/cooling. Snow Melting. Condensing Boilers. Indirect water heaters. System design, consulting and technical training world-wide. Licensed contractor, designer, installer and consultant.

B.S. University WI 1981 CONTINUING EDUCATION: Viessmann Condensing boiler and Solar water heating certification 2010, N.D.S.U. Lead Worker RRP certification 2010, Knight condensing boiler certification 2009, Wrightsoft Manual J CAD certification 2009, RPA Designer & Installer Certification 2008, Nate Hydronic/Forced Air Certification 2008, Uponor/Wirsbo advanced design school certification 2007, Buderus Wall-hung certification 2007, Power Limited License (low voltage controls) 40 CE credits 2005, Basic Hydronic Certification IPEX & Northern Alberta Institute of Technology 1998, Charter Board Member - Radiant Panel Association 1994, Residential Off-Electric to Hydronic Conversion Heating School Canadian Hydronics Council 1994, B&G Little Red School House 1993, Rood Utilities (now Auburn Technical Institute) Oil Burner School 1993 ,Tekmar Controls residential and commercial 1993, Division Manager and Advanced Hydronic Seminar Instructor for the first Exclusively Hydronic Radiant Floor Distributor in the USA 1990, Hydronic Radiant Heating Association Workshop participant with Richard c. Bourne, PE spring 1988, Master Plumbing, Hydronic, Solar Course Red Rocks Community College 1987.

Awards and Honors
2009 System Showcase Award - Radiant Panel Association

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