retrofiting hydronic over slab

Paul Bratfish

I have a 50+ year old ranch on a slab with hydronic heat and a fairly new Burnham boiler. My problem is that when the original system was installed they used steel pipe, and the contractor who repaired my first leak last week handed me the corroded remnants of the leaking suspect and told me to plan on replacing the system before the next one goes. Besides the obvious and unacceptable fix of switching over to forced air or base board what can I do?

Honeywell has a promising system but it's designed for wood frame floors. http://www.honeywell.ca/water-controls/systems/LowMassRadiantFloorHea.html
I am toying with the idea of renting a concrete saw and cutting grooves to install a new system but I fear reality doesn't mix well with that.

I realize any solution that goes over the present floor will force me to enlarge any door openings but at last I have the ceiling room.

If any one has worked through this problem or has a good idea I sure could use it.

Thanks,

Paul

Dan Peel

here's one method

We did this home in November, replacing a type L copper RFH system installed in 1950. The tubing is 3/8 Kitec, attachment is with nail in lead anchors and the clips are modified 1/2" copper straps. Thinset is applied to cover the tubing (1/2" OD) then a second application of thinset with the tile floor.

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Paul Bratfish

anyone else want to add their wisdom?

Dan's way looks good and he answered my follow up-question, (adds an inch total to the original floor level,) but I would like to get a few more opinions before I get the loan and move the family into a tent this summer.

Thanks for any help,


Paul

Paul Bratfish

Anyone else want to add their wisdom?

Dan's way looks good and he answered my follow up-question, (adds an inch total to the original floor level,) but I would like to get a few more opinions before I get the loan and move the family into a tent this summer.

Thanks for any help,


Paul

jp_2

you should be able to just cut 1-2" off the bottom of the doors, rather quite easy actually.

hr

I'd agree with Dan

Another Dan, Dan Foley, tried to groove concrete recently to install the tube... I'll let him tell you about that job!!

It would be nice to get a layer of insulation between the pour, if the old slab is un insulated. But, of course, this would cost you another 1/2" or more.

The current issue of www.jlconline.com has an article on pourable polymer cement mixes that may be a good choice for a thin overpour.

I have done 1-1/2" overpours and shortened doors. They sure do feel funny to walk through if you are 6"-4" tall, however

Be sure not to pour in and future removables, like dishwashers. I've seen that happen with hardwood re-floors!

By far the thinest radiant would be a electric mat type. This can go in a 5/16" thinset. But I wouldn't recommend electric for areas much over 200 square feet or so.

hot rod

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jw

I did mine....

Over an old shop floor, soze I could have radiant comfort in my new office in the old shop. I laid some of the "bubble wrap" type insulation, rolled out the 3/8" Kitec and attached thru the insulation with emt clamps and a powder actuated nail gun, then poured 1.5" of mud, which I stained for the finished floor. Keep lengths of tube to 200' or less. Heat the floor with a voyager.

jw

Joe_13

I know everyone here is a member

of the temple of hydronic radiant flooring, but guys there's nothing wrong with panel rads and CI baseboards right? Kitchen and bathroom floor remodels will come someday giving you the chance to have warm tiled floors. But building stoops to climb into the rooms won't do much for resale value even if you advertise radiant floors.

Tony_8

warmboard

I believe is the name of the product I would consider. Insulates from the original pad and has grooves for the new tubing to set into.

Mark Eatherton1

I concur...

Can also be used to help level sinking slabs. The biggest problem I see with this application is locating distribution manifolds such that you don't get an embolism of the brain trying to figure out your home runs etc...

The manufacturer does an excellent job of providing CAD drawings for a given job, but things change and...

That's why they provide you with two templates for the router. Curved and omega shaped offset. And don't even think about plowing through all the material in one pass with the router. Take it in 3 or 4 passes. Time consuming yes, but much easier on the ol' equipment:-)

I think that it will inevitably be shown that this stuff is better than almost anything out there. It's strong, water resistant and extremely efficient in heat transfer.
I'm sure I've seen some hand built systems, like HB's jobs, that would be hard to hold a candle against, but in any case, they're BOTH way too efficient, which is GOOD. Less energy at a lower temp to get the job done efficiently.

ME

tim smith

over concrete

We did a job last summer, 4000 sft of slab, emt straps and pound ins, one ft on ctrs for straps to keep 3/8" tube from floating. Then appx 1.5" overpour. Our knees and backs were sore after but heated floors now. Kept lengths to under 200 ft, oh please let me forget.

Dan Foley

Grooved

We did this one just over a year ago. I think I'm still coughing up concrete dust. Click on my "Find-A-Contractor" ad for more detail. To make a long story short: It took twice as long as anticipated and it was back breaking work. I would not do it again. -DF

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