Radiant slab pricing question

[djm999]

If my concrete floor is $5k, is there any ball park percentage to add to estimate the cost of adding radiant piping and the hot water setup to put it into use? Would the setup double the floor cost?

Thanks in advance for the help

 

[kert]

I'm going to have my floor poured in a month or so. I'm providing all the labor for the insulation and tubing so I can't really say on labor What I can say is that you can figure $0.75-$1/sqft for 2" insulation, and around $0.50/sqft for PEX (assuming 12" spacing). You will need some way to attach the tubes to either the insulation or the reinforcement. Whatever you want to spend on a manifold (I've seen just a series of tees or several hundred dollars for a metered manifold). I haven't started pricing boilers and pumps and such.

As far as pouring the floor goes, it really shouldn't be any more work than without the tubing.

 

[djm999]

Thanks for the quick reply. I was hoping to get an estimate of how much the radiant floor option compared to other heating options. Does anyone have any idea how a radiant floor heat build compares to a overhead heater? Plenty of nat gas in our area so I would be using that fuel source either way.

 

[BadgerBoilerMN]

We design and install all forms of heating systems for garages, but most of our work is radiant floors. The tubing is the least of most installations. The cost is in the heat source and controls. Naturally, the bigger the building the smaller the cost of boiler and controls vs. tubing.

As for radiant floor heat vs. forced air...usually the cost will double. The reason is comfort, operating cost and other features such as sealed combustion and near silent operation. You also have the versatility of choosing or changing your fuel choice from say oil, to propane, or wood, coal, pellets, corn, electricity, waste oil, cooking oil, or even plain old natural gas.

As with insulation, generally the more you pay, the more you save.

The cost per square foot is highly dependent on size, but generally our systems run from $5 to $20 per sq/ft installed. When in doubt, tube it so you can change your mind later or sell the garage at a premium as it will be "Radiant Floor Ready"®

 

[djm999]

Thanks Badger. At this point in time, I am in the preliminary planning stage of a 26' x 36'. Any ballpark guess on what cost I can plan per sq. ft?

 

[jack stand]

If you did the labor, I's say that for under $1000 all of your "in slab" stuff will be done.
That's 30pc. of 2" foam (30x$20=$600) (about 700' 1/2" pex with o2 barrier under $400)
It's not complicated at all to install the pex or insulation. If you decide to go with it write back in and I'll explain what I learned doing it myself. There's lots of web info avaialble out there.

 

[jlckmj]

I just did a 24X36, and Jackstand is pretty close, I had about $750 in the foam insulation, and about $500 in the pex tubing and elbows to bring it up out of the concrete.

I have not hooked up a heat source yet, but I expect it to be approximately another $1,000 before I am done with the hot water heating source, manifolds, gauges, expansion tanks, etc.

You could probably hang a modine type furnace in the corner of the shop for $1,500, but I have been there, and don't want to go back, cold concrete and my old arthritic bones do not mix any more.

Jim

 

[BadgerBoilerMN]

The insulation and PEX are the easy part (especially with a proper spec and CAD drawing). The part where folks get stuck is the heat source, pump, near piping and controls.

You can contact us directly about any HVAC design, but most of our work is in radiant floor heating.

 

[mx842]

If you did the labor, I's say that for under $1000 all of your "in slab" stuff will be done.
That's 30pc. of 2" foam (30x$20=$600) (about 700' 1/2" pex with o2 barrier under $400)
It's not complicated at all to install the pex or insulation. If you decide to go with it write back in and I'll explain what I learned doing it myself. There's lots of web info avaialble out there.

Just wondering where you guys are finding the 2" pink board for only $20 a sheet? I paid over $17 a sheet for 1" at HD.

 

[jlckmj]

Just wondering where you guys are finding the 2" pink board for only $20 a sheet? I paid over $17 a sheet for 1" at HD.

I got mine at Menards, I think I paid about $28.00 per sheet

Jim

 

[kert]

Just wondering where you guys are finding the 2" pink board for only $20 a sheet? I paid over $17 a sheet for 1" at HD.

Bought 35 sheets last night at Lowes for $24.09 each after a 10% coupon. Also bought 25 sheets a few months back for $10 each on CL, so on average I guess I paid a little over $18/sheet.

 

[jvitez]

It's ~ $24 a sheet for 2x8' here. It will pay me to drive to North Dakota to Menards and buy 4x8 sheets. Menards web site also has on line pricing and individual store stock availability.

 

[Highbeam]

If you plan to bellyache about the cost of XPS insulation then you ought to be considering EPS insulation. I used the 25 psi version (same as XPS) and it was much much cheaper than XPS. The manufacturer rates it for use under slabs just like XPS.

I want to say less than 15$ per 4x8x2" sheet.

 

[BadgerBoilerMN]

Warning: XPS is suitable for sub-slab radiant floors, but check the cost/R-value before you buy. It is also much more fragile and care must be taken when installing the insulation and the PEX is used.

 

[jvitez]

EPS for radiant floors. They make it in 3" thick sheets, at R 4.04/inch = R12.

http://www.plastifab.com/applications/floors/radiant_floors.html

 

[1938flatty]

Would anyone recommend installing some foam down the inside of the block or foundation wall to help with heat loss? If so how thick of foam and how deep into the ground.

 

[Randy in Maine]

I am a 40'x 28' garage/woodshop. I used 2" of foam under the slab, wire mesh to clip the 1000' of 1/2 pex to it. 4000 psi concrete with fibermesh. SIPs for walls and ceiling so everything is about R-40 or better. No rebar. Had the concrete cut to control cracking.

I put down 2" foil covered foam ~ R-14 along my stem walls to give me a thermal break between the heated 6" floor and the unheated 8" stem walls.

I covered them in 1" pine so I don't have to look at it and it is far more durable.

Came out pretty good.

 

[Dave Maxwell]

After install. With all foam and good insulation and such. If I ran mine at 50 degrees. Would it be cost effective compared to me running a force air only when I'm on shop. 3024sf

 

[BadgerBoilerMN]

I am a 40'x 28' garage/woodshop. I used 2" of foam under the slab, wire mesh to clip the 1000' of 1/2 pex to it. 4000 psi concrete with fibermesh. SIPs for walls and ceiling so everything is about R-40 or better. No rebar. Had the concrete cut to control cracking.

I put down 2" foil covered foam ~ R-14 along my stem walls to give me a thermal break between the heated 6" floor and the unheated 8" stem walls.

I covered them in 1" pine so I don't have to look at it and it is far more durable.

Came out pretty good.

2" foam? meaningless.

Wire is for reinforcing concrete, which it will not do if laid down on the "foam". PEX should be stapled to the foam in most home garages. For a 6" slab, some applications benefit from a suspended tube, in which case I would go for the wire as long as it sat on the appropriate chairs.

"Foil covered foam" is made for sheathing (walls) and likely will not meet the psi specification for any slab-on-grade. Foil lends nothing to the radiant floor heating system in a slab-on-grade radiant floor heating system.

R-10 is generally the minimum for a stem wall and should extend from the heated slab to the footing. Here it is OK to use an unrated foam.

 

[jack stand]

Would anyone recommend installing some foam down the inside of the block or foundation wall to help with heat loss? If so how thick of foam and how deep into the ground.

Down to your local frost level (depth) is best.

 

[jack stand]

After install. With all foam and good insulation and such. If I ran mine at 50 degrees. Would it be cost effective compared to me running a force air only when I'm on shop. 3024sf

On your other post, I think it was shop specialties from MT. suggested that radiant uses only 1/3 of the btu input vs. hot air. I was not aware that there was that dramatic of a difference, (if that is factual) I'm not a hvac guy or in the biz., only a happy radiant shop/home guy!

 

[kert]

On your other post, I think it was shop specialties from MT. suggested that radiant uses only 1/3 of the btu input vs. hot air. I was not aware that there was that dramatic of a difference, (if that is factual) I'm not a hvac guy or in the biz., only a happy radiant shop/home guy!

I think the 1/3 number has to do with sizing the system. With forced air, you would prefer that the system "short cycle" rather than being on all the time blowing luke-warm air. With in-floor heat, the system can be on continuously and you'd never know the difference as long as it was keeping up.

 

[KPSquared]

I got quoted around $8000 for all the valves, manifolds, and heat source.for my 30x36 shop. That ended the discussion right there. I'll never recover the excess cost. Picked up a 20', 75000 btu radiant tube heater for $1200. . .it'll do everything I need it to.

 

[Dave Maxwell]

Wish I could figure how much savings per month. Be nice to know how long the difference would take to equalize

 

[KPSquared]

I would have to go look up my cost calculations. They were based off some friends who had similar set ups. It was so insignificant as compared to my radiant tube heater that I couldn't see myself breaking even inside of 20 years and I don't plan to be at this place that long.

It's to much of an investment for me just for comfort, so it came down to money in vs. money out. Heck, that's even how I came up with how much I could spend on my garage. . . had the property valued with and without the garage. Right now I'm looking at a about a 10% gain and at a minimum, break even on my investment. . . not bad for a play space!

 

[Dave Maxwell]

Wish it didn't cost so much up front. I can get the boiler and stuff free. Its the darn other stuff that hurts so bad

 

[KPSquared]

Well, the boiler and stuff is the major cost. If I could get that stuff for nothing I would have done it in a heart beat. A couple thousand you could recover. . .

 

[jack stand]

Well, the boiler and stuff is the major cost. If I could get that stuff for nothing I would have done it in a heart beat. A couple thousand you could recover. . .

What he said! Now it's a no brainer!

 

[Dave Maxwell]

Thinking about selling my stroker motor. That will help pay for it