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Locating radiant heat tubes prior to cutting into slab

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Joined: Apr 14 2005

I am about to enlarge a shower pan into a portion of the slab that most likely has radiant heat tubing. I am trying to find out if anyone has a method to locating the tubing and if so how. I would imagine there is something similar to what the power companies use to locate undergroung cables, conduits etc. If anyone has any info on this, it would be greatly appreciated.

Ben
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Joined: Aug 12 2004

Why are you going below the surface level of the slab?

Don't think you "have" to as long as the pan slopes correctly to the drain.

I'd strongly recommend **NOT** cutting into the slab for this.

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Joined: Jan 23 2004

It's okay to cut into the slab if you have a copper system as copper can easily be repaired by a qualified contractor for a relatively small cost.

Just off the main power switch to your boiler and shut the water supply valve that comes from the water heater.

cut into the slab where you need to and when you remove the material take note of where the cut pipes are. They can be very hard to see so look close and take pictures if you can.

The pipes can be re-routed anywhere they need to be with the available space and re connected. The most important thing of coarse is to make sure they get connected back to the right place (usually pretty obvious but dont assume... let a pro do it)

Make sure they are repaired useing the same size or one size larger tubing and silver brazing all the joints (not solder)

For more information on this feel free to contact me. Also, I can provide a repair referral for you, and can be reached at y2krc51 AT yahoo DOT com

Tom

Ben
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Joined: Aug 12 2004

I've worked on a few Eichlers and many, many non-Eichler shower pans.

NONE of them were below floor level.

I can't understand why you need to go below floor level, therefore the expense of cutting into the slab and the heating tubes.

Even if you have moved a wall and are now into what was another room, you still don't need to go below the floor level.

The pitch for the drain doesn't need to be that much and if it were, you won't feel comfortable standing in the shower with a floor with that much pitch (incline).

I no longer make my own built up pans, but buy them custom made from any of the cultured marble shops. I also don't tile the showers anymore, but install cultured marble panels. Little difference in costs and the whole thing is done in less than one day, as long as the site prep meets their specifications. Only one issue has come up and is when Onyx (sp?) was used instead of marble. Semi translucent, so the cement board needed to be painted white before the panel was glued on. Otherwise they said the screws, tape, etc would show up as shadows.

Yes, heating tubes can be worked on, but it's not an easy job. The heat is wicked away very fast and if any water left in the tubing, it will also both wick and steam to cool the joint. That will create a cold solder/brazed joint, which is a weak union subject to leakage down the road.

The amount of concrete needed to be removed to expose enough tubing is also a weaken point at the slab. The back fill patch must be done right the first time, as it's going to be sealed up by the pan.

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Joined: Jan 23 2004

Ben wrote:
I've worked on a few Eichlers and many, many non-Eichler shower pans.

Yes, heating tubes can be worked on, but it's not an easy job. The heat is wicked away very fast and if any water left in the tubing, it will also both wick and steam to cool the joint. That will create a cold solder/brazed joint, which is a weak union subject to leakage down the road.

The amount of concrete needed to be removed to expose enough tubing is also a weaken point at the slab. The back fill patch must be done right the first time, as it's going to be sealed up by the pan.

Yes... It needs to be done right... hence the proffesionals shounld do it.

Of coarse, you should try to avoid cutting the slab if you can... But that wasn't your question. Repairing radiant pipes IS easy for someone who does it for a living.

To answer your original question. There are sub-surface pipe locators that can find the pipes. It's time consuming and difficult because the system in the slab is all tied to a 6" steel wire mesh that the pipe locator picks up making it difficult to pinpoint the radiant pipes. All in all it doesn't help that much. It takes less time to just do what you have to do and braze them back together. The brazed joint is stronger than the pipe itself so durability is nothing to worry about. The system performance will not change.

Tom

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Joined: Feb 3 2005

Ben wrote:
I've worked on a few Eichlers and many, many non-Eichler shower pans.

NONE of them were below floor level.

I live in the fairglen track and my Master Shower is below floor level, and I've gone to several open houses in the neighborhood and I've seen many showers are below the floor level.

not so sure "NONE" is the correct word

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Joined: Mar 16 2005

My Eichler is a 1972, and the MBR Shower is about 3" below the floor, next to the toilet. If he is removing 3" think concrete to expand the shower floor, then he will be taking away everything in the section -- if he hits piping, it will need to be re-routed, not repaired. If the shower is at floor level, then he may be "shaving" the top to pitch it to the drain and could hit or glance something in the slab. As space efficient as Eichler was in all things, the shower was adequate size and it would look funny to have the drain offset from the middle if 1 side of the shower floor was moved out. In any event, this sounds like something I would avoid but nothing ventured nothing gained.

To the original question, I don't know how to find copper or steel tubing underground; kind of a stud senor for metal.

Ben
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Joined: Aug 12 2004

paul_h wrote:
Ben wrote:
I've worked on a few Eichlers and many, many non-Eichler shower pans.

NONE of them were below floor level.

I live in the fairglen track and my Master Shower is below floor level, and I've gone to several open houses in the neighborhood and I've seen many showers are below the floor level.

not so sure "NONE" is the correct word

Notice said: "I've worked on"..."none of them"

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Joined: Jan 4 2004

I personally have remodeled about 25 Eichler master bathrooms (yes, the ones with the phone booth showers), the original design, while interesting in that you step down in to the shower, is substandard because:
1. they never included a shower pan water tight membrane, such as tar, copper, or pvc, which is installed beneath the tile and mortar base
2. the drain connections are 1-1/2" DWV, which is currently illegal in most municipalities
3. because of reason 1 above, gray water will leach into the soils, and eventually the water table.

Granted, such requirements were not in place at the time of construction
(nor did we know about asbestos, ozone, carcinogens or other fun stuff),
they are now in place due to decades of trail and error.
I am inclined to agree with Ben regarding avoiding saw cutting/removing additional concrete in the adjacent area as an approach to enlarging the shower. With the exception of the roman tub in the X-100 (steel prototype Eichler) the sunken shower pan does not serve any true design function. It was easier when building the foundation to add a couple 2"X4"'s to box off the shower pan when pouring the slab, rather than form a curb, mud over it, and attempt a watertight pan above grade (back then, they predominately used copper pans or hoped that tile mud (cement+sand+lime or clay) and plastic sheeting would do the job.

Of course, if you really are married to the concept, you can saw cut, repair/reroute the radiant heat lines, move the drain, re-pour, float out the affected area, then hot mop, or line the pan in some other method.

If you simply demo/chip out the tile/concrete at the bottom of the pan, dig out the dirt around the drain, have a plumber snap in a 2" drain/trap system, center the drain in the new pan, pour it flush with the existing slab with common redi-mix, set a cultured onyx, marble, or granite pan on top of it after it the concrete cures, (or frame in backing and a curb, pitch the pan with tile mud so that it slopes to the drain, have it hot mopped, or line it with a PVC shower pan, then mud it with tile mud, so that it can be covered with tile), you will have cut out a few steps, save time and money as well as having to repair the radiant heat, which has to be done by professionals at about $110-$130/hr, because it needs to be braised rather than soldered, pressure checked etc.
I guess if your point is to preserve the original design, then enlarging the shower sort of defeats the whole purpose.
The proceedure that I have described is the only way that the SM co Building Dept will pass a shower pan inspection, so I am certain that I am correct in assuming that it complies with current standards.
Have fun! It is a pretty fun project (aside from the digging part).

renman

Joined: Mar 2 2004

How deep can you go before having a problem with the original drain line....as in 'water needing to run uphill'?

Ben
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Joined: Aug 12 2004

Randy at Dura-Foam wrote:
How deep can you go before having a problem with the original drain line....as in 'water needing to run uphill'?

Not much...

Brother has a "mother in law" appartment out back in his 2 car garage (alleyway back there). The toilet and shower drain is about even to each other on the slab. Then about 12 inch drop to the runner to their main sewer line to the alley.

Nephew is living there, just out of the Navy looking to be a fireman/policeman.

This winter they had poop backed up into the appartment. Significant amounts. Seems that the older sewer lines in San Mateo also has strom drains dumping into them and when it rains, they over flow or back up a bit.

"Back pressure" will "lift" the poop up a ways.

So very dependent on how your sewer lines are setup in order to answer "how deep".... ;)

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Joined: Oct 6 2003

Thanks everyone for the info here. I want to move my toilet over 8 to 10 inches in a terra linda Eichler. Can anyone tell me if it is common to find radiant pipes that close to the toilet and bathroom plumbing? If so, how deep is the pipe and how thick? I was thinking of exploring carefully using a chisel.

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Joined: Apr 12 2003

We hired a heating specialist prior to slab work who owned a device that could pick up heat differences subsurface. We simply turned on the heater, allowed the pipes to warm, then he took readings and taped lines on the floor delineating the radiant tube routes. Most of the heating companies advertising in the Eichler newsletter can probably perform the proceedure.

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Joined: Mar 20 2003

You can try this DIY method:

Turn on the radiant heat on a cold slab. Within an hour or two, the slab is not uniformly heated but the area where the pipes are will become the hottest first. You can buy a laser temperature probe like this one:

http://www.professionalequipment.com/xq/ASP/ProductID.717/id.22/subID.17...

You can measure the temperature of the slab surface and find the hot spots which is where the pipes are. You can also skip this and spray water on surface of the slab with a mist of water. Where ever it is the hottest is the place where it evaporates first.

Keep checking the slab when you turn the heat on. Eventually it will become more uniform and you won't be able to easily tell where the hot spots are. Don't do this in a heatwave since as you know, it take a few days for a heated slab to cool off and you will be sweating it out.
/Lynn

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