Ceiling Radiant heat - copper tubing

Dan J

We are redoing the kitchen and moving a wall which disturbed the ceiling. My heating system is radiant heat - forced hot water, in the ceilings. The copper tubing is attached to a steel mesh, then ferrin strips and finally the floor joists above. This is completely covered with 1 1/2 inches of "mud". With the work I am doing, I will need to make holes in the existing ceiling which will then need to be recovered with blue bard. I would love your opinion on a couple of matters. Is the extra ceiling surface going to hurt the performance? Is the risk of damage during the new ceilings installation (nail through pipe) worth considering replacing the entire system immediately? I only have oil available in my area. With a blank slate, what is the best system to convert to?

[Deleted User]

cieling heat

I've had to replace several systems. Due in part to the client wanting central air, but mostly because the copper tubing was rotting out. Because of the plaster. These homes were built back around the mid 1940's. So you may want to consider another alternative.

Mike T., Swampeast MO

If your ceilings were still in good shape with little or no cracking, your system is likely one of the finest. (It took plasters a while to come up with a good mix to ensure no cracking.)

If you've been happy with the heat previously, PLEASE get someone in to evaluate and conduct the heating portion of the remodel. There is ZERO reason to destroy good work if not utterly necessary. The system likely dates from the late 50s through early 60s and probably has MANY decades of service life remaining.

This sounds like a DIY expansion with which I have ZERO problem. BUT, when it comes to this form of heat, call in someone knowledgable lest you have unneeded expense and reduced comfort!!!! Well, you can always study deeply and delay your project for a few years as you learn...

Dan J

Ceiling heat

Thanks for the response. How do I go about finding someone with this knowledge when these systems went out of favor thirty years ago? My contractor is younger than me. I would hate to lose the system years before it has to be replaced. From everything I learned today, it sounds like we can remodel around it and layer the new blue board over it to cover the damage done moving walls, etc. Any other pointers are always welcome. Happy Thanksgiving.

Gordy

Curious

Curious to how you knew the copper was "rotting Out". Leaks?

Mark Eatherton1

Even more curious...

what is it in plaster that would cause copper to rot?

ME

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Gordy

Exactly Mark. Sounds like a water quality issue, from what I have learned.Notting Mike that several systems you have dealt with did this. Mike are these all in the same area? Same water supply?
Its nice to play a little detective work with issues like this ,it helps everyone out. No need for someone with a perfectly good system to tear it out on the premise its going to disintegrate. There are reasons and I doubt its the plaster.

Paul Pollets

Lime

!!Lime can do the trick. Many leak because the copper is tied to the lathe with steel wire---electrolysis burns a hole thru the pipe

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Gordy

Paul

Paul, elaborate on this reaction a little please.

Gordy

Dan J

picture

This is what we found when we took some of the ceiling down. The pipes are only 7 inches apart. Is that the way I should expect to find the pipes throughout the house?
Thanks

Gordy

picture

You got it. Lots of copper, at least thats how my system is.
Looking at the picture I notice a couple of the tubing runs are like new and the majority have a gun blue or black finish to them what is their condition compared to the newer looking?

hr

Actually

for electrolsis or galvanic corrosion to take place you need two disimilar metals in contact AND an electrolyte, such as water.

Electrolysis corrosion usually involves a stray electrical current in the tube or wires touching it.

Galvanic corrosion being the disimilar metal corrosion.

When they test metals to place them on the galvanic Series table I believe they use a salt water as the electrolyte. Fresh water is a weak electrolyte, distilled or condensate very weak, and they say steam will not act as an electrolyte at all.

Generally copper corrosion in concrete or cement based products has more to do with "other" ingrediants that were mixed in. Fly ash, blast furnace slag, and other products have been used as fillers over the years. But still, you need moisture to make the corrosion happen.

Copper in a slab, or below the slab, in the presence of wet ground and possibly high sulpher fly ash, or other fillers, is most likly what led to premature copper tube failures in the early copper tube slab jobs. and steel pipe for that matter.

I think the Levitt homes were poured with wood 2X4 suspending the tube. This is probably where the moisture wicked in, or ground water issues, possible bad drainage or backfill practices.

Keep it dry and encased in the concrete pour and concrete an copper get along fine. Easier said than done:)

Think I would still have a plan B in place if you are doing a major remodel with an old ceiling radiant. It's not a matter of IF the system will leak, but WHEN :)Might be better to up grade now than play the odds.

hot rod

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Gordy

Lime

So Hot Rod, being that lime is a base that is not playing a role correct. Going by some of the reading in the hot tech topics under "concrete corrodes pipes" here. Thanks for your clarification Hot Rod. Hmmm stray electrical current, bonding ones service to the water pipes per code may have consequences if something is not quite right.

Gordy

[Deleted User]

Same area

All of the homes I worked on, were in the same area, Madison N.J.. Purhaps built by the same contrator, and with city water. I did several repairs, and each time i found the pipes were pitted, and thin. the repair couplings slide too easily over the old piping. The home owners were disappointed about losing the cieling heat, but understood.

hr

Not the lime

lime itself is not an enemy of copper. Here are some lime uses from the lime webpage

USING LIME TO TREAT DRINKING WATER

In terms of annual tonnage, lime ranks first among chemicals used in the treatment of potable and industrial water supplies—in 2001, nearly a million metric tons. It is used by many municipalities to improve water quality, especially for water softening and arsenic removal. Indeed, the American Water Works Association (AWWA) has issued standards that provide for the use of lime in drinking water treatment.

Softening--In water softening hydrated lime is used to remove carbonate hardness (caused by bicarbonates and carbonates of calcium and magnesium) from the water. Hardness caused by other calcium and magnesium salts, called noncarbonate hardness, is generally treated by means of the lime-soda process, which entails the precipitation of magnesium by lime. The co-produced calcium salt reacts with the soda ash to form a calcium carbonate precipitate. Lime enhanced softening can also be used to remove arsenic from water. Recent changes to the national drinking water standard for arsenic have increased the need for this treatment. The U.S. EPA has issued new guidance on enhanced lime softening to remove arsenic, see http://www.epa.gov/safewater/mdbp/coaguide.pdf.

pH Adjustment/Coagulation--Hydrated lime is widely used to adjust the pH of water to prepare it for further treatment. Lime is also used to combat "red water" by neutralizing the acid water, thereby reducing corrosion of pipes and mains from acid waters. The corrosive waters contain excessive amounts of carbon dioxide (carbonic acid). Lime precipitates the CO2 to form calcium carbonate, which provides a protective coating on the inside of water mains.

Lime is used in conjunction with alum or iron salts for coagulating suspended solids incident to the removal of turbidity from "raw" water. It serves to maintain the proper pH for most satisfactory coagulation conditions. In some water treatment plants, alum sludge is treated with lime to facilitate sludge thickening on pressure filters.

Effect on Pathogen Growth--By raising the pH of water to 10.5-11 through the addition of lime and retaining the water in contact with lime for 24-72 hours, lime controls the environment required for the growth of bacteria and certain viruses. This application of lime is utilized where "phenolic water" exists, because chlorine treatment tends to produce an unpalatable water due to the phenol present. This process, called "excess alkalinity treatment," also removes most heavy metals.

Removal of Impurities---One of the most common methods of removing silica from water is the use of dolomitic lime. The magnesium component of this lime is the active constituent in silica removal. Lime is also used to remove manganese, fluoride, organic tannins and iron from water supplies.

There were some other issues about working with old plaster in a recent JLC, as I recall. Health issues of some sort.

hot rod

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