Replies

1. 
   calvin | Aug 23, 2011 10:30am | #1

   well

   If you were to use an engineered hardwood, why not just embed the hoses in the concrete?  Utilize the mass you have.

2. 
   buildergene | Aug 31, 2011 10:28pm | #2

   I've never used boards, just regular tubing patterns and love it.

3. 
   joeh | Sep 02, 2011 04:47pm | #3

   What is the floor on?

   PEX in concrete works best, are you building a slab on grade, basement with wood floor system? 

   Need more info to advise but sounds like you're spending a lot more than necessary. You can do gypcrete with pex over ply floor, lot of ways to do it.

   More info would help.

   Joe H

1. 
   lancepoo | Sep 02, 2011 11:59pm | #4

   in floor heating

   Joe, We are using wood floor joists, with plywood sub floor, and our concern is we want to use solid wood flooring, not engineered or laminate, and are concerned  about the higher heat required for the concrete bed verses the Warmboard.  Also the wood cabinets may react to this higher temperature.  Thanks for your input.  Lance

1. 
   sapwood | Sep 03, 2011 11:40am | #6

   I've had radiant heat in several buildings so I've some experience. But I'm hardly an expert. I'd advise you to do a ton more reading, or hire an independent heating consultant. This is an expensive, and rather permanent, undertaking... don't enter it uninformed.

   Here's my two cents worth of knowledge: Radiant in concrete isn't necessarily better than any other way, its just different. Concrete and gypcrete are high mass materials. Heating those materials with buried tubes takes some time (as you are probably well aware). One doesn't simply flip up the thermostat and have a warm house. It takes a couple of hours. But, the heat produced is then well distributed and steady, assuming the sun doesn't come out and give you a boost of warm sunshine.

   Warmboard is a low mass product. The reaction time is significantly less than with any high mass system. Warmboard also serves as the subfloor, thus saving some construction materials as well as labor.

   For any system, one sizes it according to how much heat input the house needs to stay the temp you want. BTU's in via hot water to cancel BTU's out via heat loss through walls, ceilings, etc. Your hot water maker will be the primary determining factor in efficiency.

   Knowing what I know about the topic and given the two choices: concrete vs. warmboard, I think I'd choose the warmboard. But this makes most sense for my climate. We have cool mornings this time of year so a little heat would be nice. This short order need is best supplied by a low mass system. If I had a high mass system the slab would just be getting up to temperature by the time the sun has heated the outdoors enough to open windows and doors. 

   Actually, here in the PNW, I actually have an in-slab system for my shop. Didn't have much other choice there since I wanted a slab for working purposes. I don't heat this building until it stays cold throughout the day.

2. 
   Tim | Sep 20, 2011 03:15am | #7

   Surface temperature

   is the limiting design parameter when using solid hardwood over an infloor heating system. 85 degrees F, as I recall, is the limit if you want to limit damage to the wood. The manufacturer's design software will determine what water temperature is required to meet this limit. Using hardwood flooring will limit the amount of heat you can supply to a room so very good insulation and/or supplemental heat will be required.

   Systems based on tubes above the subfloor don't operate at high water temperatures, but the supply temps are based on the details. You do not want to run the tubing under the cabinets, BTW, regardless of the temperatures involved.

   Any of the "board" systems, typically a piece of plywood with a groove cut in it on a thin sheet of aluminum to distribute heat evenly. Some will claim one version is better than another. I designed systems based on the product my company sold, Wirsbo (Uponor) and Rehau.

   If you are going to nail the flooring down, the tubes need to be visible for obvious reasons, so imbedding them in a substrate of gypcrete or lightwieght concrete is not a good idea.

   Ultimately, you should contact a knowledgeable installer/designer professional to help with the details.

4. 
   joeh | Sep 03, 2011 12:38am | #5

   Where are you getting that information?

   The water temp isn't going to be higher for concrete, Warmboard salesman give you that story?

   Joe H