Radiant heat in plaster ceiling

John at Fraser Construction

We are a general contractor building a new house in chicago. It is all plaster construction. We would like to embed radiant tubing in the plaster ceiling as a primary heating source, backed up with fan coils. It is 3 coat plaster, 1 1/8" thick. (Not veneer plaster). We have been cautioned against using PEX tubing by the manufacturers due to lack of testing for this specific application, because of the possibility of plaster cracking. What would be the appropriate tubing to use and has anyone installed this system?

Steve Minnich_2

Please read my posts

under "Cunundrum/Radiant over slab". There are ways to attack this and I can help you as I am located in Hoffman Estates, IL.

Steve, Radiant Comfort Systems

Gordy

Ceiling radiant in plaster

My house was built in 1952. Ceiling radiant through out all 3/8" copper tubing no leaks plaster looking fine 50 years of service says alot!

Ed_5

radiant in plaster ceiling

I too have 3/8 coopper in my plaster ceiling, works great but ceiling has developed many cracks over the years. I'm not the original owner and I think at one point the temp was just too high. I'm going to cover with drywall. I live in the Chicago area and I've never had the need for a back up heat source. Water temp is 120 out of the boiler. house was built in the 50's. no insulation inthe walls. Anyone have any good tips for locating copper tubing in plaster ceiling????? -Ed

Alan(CaliforniaRadiant)Forbes

Thermal Imaging

will give you a good x-ray view of your layout, but it's kind of expensive.

If you know someone who has an infrared thermometer, you will be able to record temperature gradients across the plaster. The highest temperature will pinpoint the tubing. I'd start with a cold ceiling and turn the heating on; that way, the temperature differences will be greater.

But you know what, I've never done it so I'm just guessing.

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Richard Gilbert, P.E.

Hydronic radiant ceiling

We're the consulting engineer for a Beverly Hills homeowner who wants to
radiantly heat his outdoor covered patio. A previous contractor tried
using PEX in the slab floor on 12" centers and it doesn't do much. We
are going allout with a radiant ceiling using 3/4" hard copper on 2 1/2"
centers. Our heat flux at the ceiling is approaching 300 Btu/sq.ft.
Anyway, we're using your heat loss chart dated Sept. 16, 2000 for
tarnished copper tubing. My question is, how do we tarnish the copper?

Richard L. Gilbert P>E>

Alan(CaliforniaRadiant)Forbes

Richard

I didn't see any smiley faces after your question, so I presume that was a serious question.

No need to tarnish the copper; it will do so by itself.

We don't do much patio heating up here in San Francisco, but I'm curious why the installation you describe isn't working. Yes, 12" centers is perhaps a bit far apart, but in So. California, you should be able to feel it. Have you tried different water temperatures?

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Gordy

Tubeing locator

Just go to Radio Shack and for 40.00 buy a hand held infrared thermometer. Works great system needs to be in heating operation to get a good reading,But you find the pipes right on. I used it to install ceiling lights.Just run it up tight to the ceiling and sweep across it will register a reading highest should be your pipe.
Also I don't know how bad your ceiling is but it can be fixed without the need of drywalling if cracks are only hair line

Gordy

300 Btus sq ft. Wow you could have a pig roast in there set up the rotisere.

Ed_5

Thanks

for the tip on the IR thermometer. I will surely give that a try. Cracking in some rooms is pretty bad, that's the reason for the drywall. I'm installing ceiling lights as well. Thanks much -Ed

tim from Reed Wright

ceiling radiant

John, I have seen quite a few plaster and 3/8 copper tube jobs that hold up well against cracking. One of my old time Mech. engineers (80+ yrs old) has been designing those things up till current days. I still take care of appx a 5000 ft townhome that he designed about 10 years ago when it was built. They work pretty good.