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reveriereptile 04-06-2012 04:15 PM

How hard is it to install radiant in-floor heating in a new slab?
My husband and I are building a house this year and I'd love to put in a hydronic radiant heating system. We are going to build a chalet with a prow front. Due to the high ceiling and cold winters I thought this heating system would be best for us in the long run. Due to budget I'm trying to figure out if it is something we could do ourselves to save money.

I was thinking of calling a company and give them the floor plan and have them design the tubing pattern and buy the materials. This would be a new construction slab on grade which I've seen is lower on costs for installing and easier and easier to do. We plan to build the edge walls up a little higher with cinder blocks to help protect the walls against snow.

From what I've seen in videos and read it seems pretty simple as far as installing the tubing into the floor. Seems that most of the labor is just laying out the tubing and zip tying it to the rebar after you get the ground and insulation ready. I did see that insulation is a major factor and to bring it up the walls some. Is it all that hard to do if we follow the layout and spacing the company gives us for the tubing?

I haven't come across much information on setting up the system though. We would want a closed system. The water would be from a well so I don't know if that is doable for us to get our water for the floor and for our shower through the same well if the floor is on a closed system. Not really sure how it works. I wouldn't mind more information on that if anyone has some.

The main floor (slab) is only going to be around 1,085 sq. ft. and will be stained concrete without flooring on top unless we decide to put tiles on later in the future. We might only have 2 heating zones on this floor. Our half story I'm not sure about installing the in-floor heating for it. It will only be our loft, master bedroom, WIC, and bathroom. We could use a different heating source for it. That floor is only 617 sq. ft. If we did install the radiant heat we wouldn't need it for the full 617 sq. ft. since I don't need a heated closet or loft. The ceiling will go all the way up. We like it high and not cut off before the peak. We are having reversible ceiling fans put in.

One other thing is I don't know if we should get a boiler or a high quality water heater (separate from the one for our showers)? For it not being a big area I don't really want to spend money for a boiler if a water heater would work fine for us.

Does it seem like something we could do ourselves? The big question is would it save us much more doing it ourselves than paying someone to zip tie tubing to rebar? We already plan on doing most of the house work ourselves except for the electrical, well, septic, foundation, plumbing, and framing. My husband's sister built her house 2 years ago and did what we plan to do and hers turned out really good. She didn't do radiant and regrets not doing it but plans on putting it in when she adds on an addition.

biggles 04-07-2012 08:08 AM

check out this site on that HWH idea and you would have to have a closed loop on that radient. that is so your reheating the loop water not the incoming well with a pressure regualator on the inlet and expansion tank...standard HWH at HD/LOWES are low temp for domestic use,boilers run 160F-180F temps for heating even with the statndard baseboard installs to make a stat setting of 68F might consider a tankless heater

GarrettP1 04-07-2012 09:05 PM

I did this in my new home.

It's not hard at all, but I recommend that you pick up a book on the particulars of radiant heating.

In my (concrete) foundation, I put down welded wire (before the pour), and then used zip ties to hold the PEX tubing in place. A quick pressure check is done before the concrete is poured (to make sure you didn't puncture the tubing), and then you're done. I'm in the Florida panhandle, so I skipped the insulating barrier usually placed between the ground and the foundation due to our milder winters.

The book you purchase will help you layout the pattern for your tubing.

Good luck!


REP 04-07-2012 10:55 PM

The most cridical component is the design and the heat loss.Most of the rest is grunt work.
Infloor is prone to air problems so do not try to save money on shut off valves,i.e. before and after circulator pumps.(Do zone with pumps)If you valve off anything that could go bad in the middle of the winter,you won't have to dump the whole system to replace it and the spend hours refilling the system when repair is done.
Use only a Spirovent for air elimination.It is in a class by itself and nothing esle is even close.
Having an indirect hot water tank is better than a tankless coil in the boiler.Either way you are going to need to control the water temp going to the infloor vs going to the water heater.You could use this system for the loft/bedroom area.Just use high density fiberglass under the tubing.If the r-value is 3 times what is above the tubing it will work great.Nothing like walking around in bare feet in your bedroom and bathroom when it below zero outside.

reveriereptile 04-09-2012 11:03 AM

Thanks for the replies. I've been checking out the site since they had some good information. I'm thinking about doing a price quote. Has anyone ordered from them and are they worth using?

From what I've read on a few sites it seems like you don't install it under the toilet or tub areas. I was going to do the square footage for the price quote and was just going to do a path (main walking area) in the bathroom and not mess with putting anything under the tub, sink, and toilet. I also wasn't going to put it under the stairs or in the closets. Do I need it under the kitchen cabinets where the sink and dishwasher aren't? Wasn't sure if it would be just easier or a waste of money.

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