Grooved Concrete? - DF

Dana Zaichkin_2

Sounds like dusty fun. I think the electric mats are a pretty good idea - of course I live where electricity is produced pretty cheaply by grinding up little salmon in hydoturbines. Or what about building a 4" thick wainscoating on the walls at the ends of the tube runs and running the end loops up into the wall? ...or maybe making the turns in the cabinet toe-kick - but then you get pre-heated food.

Now, these grooves aren't changing any structural integrety are they?

Best Regards

DZ

Dan Foley1

I am installing radiant floor heat in the kitchen of a 1928 mansion in Cleveland Park, Washington D.C. The kitchen is on a 7" thick suspended structural concrete slab and was originally heated with CI radiators. I originally intended to attach my pex tube to welded steel mesh and have the GC pour a 2" concrete "cap". The ceiling is 10' tall so height was not an issue. The finish floor is 1/2" marble.

The architect and homeowner recently vetoed my idea. They did not want a threshold from the dining room hardwood floor to the kitchen. There would have been a 1-1/2" difference in floor height. Instead the GC suggested cutting grooves in the existing slab with a concrete saw (the GC, not me!). The radiant pipe would then be installed in these grooves eliminating the 2" cap. Has anyone ever tried this? What would you "grout" the grooves with? How would you attach the tube? Anything else to watch out for?

TIA -DF

hr

Big fun

How will the cut the return bends? A diamond router bit! I would consider PAP for ease of installation.

Years ago I did a rubber tube Onix job for a Heatway employee. We glued down to an exisiting concrete slab with construction adhesive (liquid nail)and poured a cap over it without 1 floater! I'm not sure how pex products would react to construction adhesives, however.

Interesting project, I'd be up for that challange:) There are lots of ways to saw concrete, I have even seen concrete cutting chains for chain saws! Start looking up concrete cutting contractors for ideas. A walk behind saw would easily cut the straight runs.

Copper tube or steel pipe with welded short turn bends, be easier to keep "in the grooves"

Where there is money there is a way is my motto.

hot rod

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Dan Foley1

Great ideas HR

No question this will be a T&M change order. I like the the idea of P-A-P pipe with construction adhesive. I will check with the manufacturer first. I had the same reservations about the return bends but the GC seems to think he can do it.

I will "layout" the piping runs with chalk lines and spray paint and the GC will cut the grooves. He did a test run today. He cut a 5' long groove with a diamond saw and brick chisel & hammer in about 15 minutes. Hard work though, and lots of dust! Not my cup of tea. I will keep you posted. -DF

hr

Dusty but do-able

less than 4 minutes per bend. I would go with 3/8" PAB and buy a 1/2 wide diamond wheel. I paid $60.00 for this 1/4" by 4" wheel pictured here.

Or for $25.00 per bend I'll carve them for you send me a ticket! You don't have mosquitos there do you

hot rod

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hr

Another trick

if you can't find a 1/2" wide wheel for his saw you can put two 1/4" side by side if his arbor will accomodate them.

You should be able to find a 1/2" wide wheel and drop the hammer and chisel nonsense

I would guess 10 - 15 feet in fifteen minutes once you get the procedure. The big walk behind wet saws are much less of a dust mess factor.

hot rod

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Dave Yates (PAH)

At the risk of inciting ire

have you considered electric radiant mats installed under new tile/marble? Almost no perceptable rise in floor height and economical operation when weighed against cost for all that grinding. Whole lot less dust too! Nice Btu outputs per sq ft too.

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Colin

Floor patch Colin

Dan, We use a product called Rocktite. It's a patching and anchoring cement. It does get warm as it cure but I don't think it would damage PAP or pex for that matter.

It's made by Hartline Products Company Inc.
4150 Mayfield Road
Clevland Ohio 44121
216-291-2303
fax 216-291-4482

Good Luck and let us know what works out for you.
Colin

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Dan Foley1

Thanks

Thanks for all the replies. I will post some pics as this one progresses. -DF

antman

Curious about insulation.

Just wondering since with radiant we always talk about the importance of insulation under a radiant floor to prevent downward loss, how would you address an installation such as this?

Ant

Jed_2

Did I miss something?

I don't see the recommendation for a Warm Board type sub-panel here. There was a discussion about overlaying on concrete a while ago. Is it not recommended on concrete? There seems to be an allowance for some elevation make up. And, yes, I would think the underside of a 7" concrete floor would want to have significant insulation. Heck of a fly-wheel.

Jed

Dan Foley1

Warmboard

Jed, I recommended both Warmboard and Quik-Trak as I have used both with excellent results. The problem is that you cannot install the marble directly over these products as it will crack. I would want to see a minimum of 1/2" Durock over the Warmboard. 1-1/8" Warmboard + 1/2" Durock + 1/2" marble = a threshold between the kitchen and dining room - no go. Believe me, I have explored just about every option. I am not thrilled about grooved concrete.

Regarding the insulation: The basement is heated. Directly below the kitchen is the boiler room containing a 400,000 BTU boiler and 6" and 4" steel heat mains. It stays fairly warm in the boiler room so there is minimal (if any) downward heat loss from the kitchen floor. The space on both sides of the kitchen are heated as is the space above. Only the front and back walls are cold walls. With the six burner Viking stove and commercial Sub-Zero refrigerator, the actual heat loss of the kitchen is quite small. This is probably more of a floor conditioning job than a heating job. Thanks for the comments. -DF

Concerned

No insulation?

You definetly need to insulate under that floor. If not you will have a wonderful radiant ceiling in the boiler room. Yes the boiler room will be warm, but when the boiler is in the off cycle and the large mass of that kitchen floor is still warm you will lose a lot of heat downward. I would probably recomend wirsbo quik trac with at least 1/4" of rock board over that, then insulate w/ r-19 under the floor.

Mike Kraft

Wirsbo sez.............

(from the CDAM)Suspended Floors: Downward loss exists in areas with a heated space below.If the heated area below uses the same heat plant as the area above,the loss does not increase the total load/heat plant load because the heat is not lost to the structure.If downward loss to the heated space below exceeds either the upward load or 10BTUH/sqaure foot,insulate the suspended floor.Without insulation the room temerature below is impossible to control.

From Dans description of the kitchen he's warming the floor.Not heating the room.The mechanicals below sound pretty warm with a 400K boiler not to mention DHW,piping etc.Ultimately your concern will be noted.I'm sure the numbers dont lie:)

Keep us posted Dan.

very curious cheese

Gary Hayden_2

Concrete Filler

Dan - here is the product for the filler. Make sure that it does not damage the O2 Barrier and you are good to go. You will like this product also - expensive but the best.



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