Hydronic Floors & Hot Water Heat

[rScotty]

I've been thinking about building a workshop & shed with a hydronically heated floor. Hot Water Heat. Anyone done this lately? What I'm thinking of doing is pouring a slab with the flexible piping right in the concrete.
Open to recommendations of a good type/brand name for the pipe in the concrete slab. And any other hints. I've heard that PEX is one possibility.
thanks, rScotty

 

[ededic]

Hydronic Floors & Hot Water Heat

We did!

New cottage/retirement home near Lake Michigan
New cottage/retirement home near Lake Michigan

Start with post #37

 

[RNeumann]

Yes PEX is the way to go. They make 2 common grades of PEX. Make sure to source PEX designed for heating.

A shop with power and gas (or just a good amount of power) would be a great place for in floor heat.

 

[CalG]

Floor heat is good

Plastic pipe is inexpensive and reliable.

Oxygen barrier types May be better.

Check your pipe work for leaks BEFORE the concrete gets hard. It is easier to poke a hole in green concrete.

My self, I have placed two radiant floors. The kitchen Dining room is SOG with a "thin slab" holding the tubing. A slip sheet between, with ceramic tile and stone surface. Sweet floor!

The other is my lab. Imbedded tubing in a 5 inch slab. Pre finished cork flooring tiles over.

Both work well. Both are heated by an oil fired boiler (it doesn't boil ;-)

Thermostatic control gets to be an issue,

Control the slab temp? or the air above? I favor the slab temp. 2 degrees F above dew point all summer. (min) and "warm under foot" all winter. Man that feels nice.

The air is heated with the wood stoves, if you can say that. I prefer to not heat the air. Air just goes out the cracks, and if it can not, feels stale and oppressive.

 

[Aquamoose]

Pexheat.com. You’ll read that oxy free pen is a must. Do lay the tubing regardless if you think you plan to have it or not. Tubing is cheap anyway.

I did mine with infloor thermostat. Lots of info throughout.

 

[rScotty]

Re: Hydronic Floors & Hot Water Heat

We did!

New cottage/retirement home near Lake Michigan
New cottage/retirement home near Lake Michigan

Start with post #37

OK. Thanks Ed, I'll go read that. And I see some more replies, too. So it looks like it's research time. & what better place than TBN?

This project should be fun & super simple. It's just a floor for a workshop shed with one wall attached to the house. And small enough so that I can afford to experiment with any technique or material. I'm thinking to use a slab on grade about 6" thick and not yet decided whether to embed the tubing in the slab (top or bottom?) Or do as CalG did & put the tubing as an additional layer on top of the slab. Hmm.... If I embed it in a one simple pour, is it common to insulate the slab from the sand below? That could be difficult. Seems like the tubing would be better on top of a pour and then within a one inch additional pour. Why/whynot? What tubing to use? I see PEX, PERT, ONIX, & PAP. Prices are roughly the same.

Expense is less important than fun for this project. In deciding which way to go, my main goal is to make it efficient and to satisfy my curiosity. This simple shed floor won't cost much no matter what I do, so comparitive expense doesn't matter.

I'm not a total novice - but nearly. I once was part of a floor pour installation using IPEX Kitec XPA tubing in a suspended slab. The tubing was stapled to OSB subfloor & slab poured on that. I still have crimping tools for 1/2" & 3/4" copper rings on IPEX. So that kind of IPEX PAP tubing is a possibility. Much of what I think I know is probably out of date, especially for materials and techniques.

rScotty

 

[buickanddeere]

Insulate between the slab and the earth below no matter if you floor heat or not .

 

[boomer1025]

Insulate between the slab and the earth below no matter if you floor heat or not .

:thumbsup:

 

[rScotty]

Insulate between the slab and the earth below no matter if you floor heat or not .

I agree with insulation. My first idea is to get some of the 1" thick purple foam board from Home Depot, cut it into 18"x 36" rectangles, and space those rectangles about 3" apart

with 2x4 blocks. Then lay down whatever Hydronic tubing we come up holding it crudely in place with using push-nails & either PVC conduit clamps like this....or maybe just tape the tubing down and push some nails through the tape.

Then pour the slab right over all until it comes to the top of the 2x6 form. Steel or no steel?
rScotty

 

[ovrszd]

Check out Supplyhouse.com. great price. Free shipping.

Gravel base. Plastic covered. Pinkboard. PEX pipe. Steel. Then pour concrete.

I recommend 2" pinkboard insulation. Lay the PEX on the pinkboard and staple it down. Supply house has the staples. They also have the elbow sleeves to protect the PEX where it comes thru the concrete.

Problem with doing a small area is you still need the heater, expansion tank, pumps, manifold with valves. Makes the cost per square foot pretty high.

We just finished pouring a 1875 square foot shop floor. When operational it will have a cost of $2.80 per square foot.