HOT tile floors

**Katherine Keil** · 12-04-2019, 04:01 AM

In my condo, several months ago, there was a hot water pipe leak under the slab that heated up the tile floors. They were so hot, you could barely walk on them barefooted. The air conditioner ran 24/7 and could not keep the unit cooler than the 90s. The slab was taken up in a guest bedroom closet. The water removed. The leak repaired. The slab poured, etc. Now a couple of months later, there are some warm tiles in the master bath area. There are two sinks in that area. At times I have had only HOT water coming from both cold and hot taps. Other days, I have to let the cold water tap run a bit to get rid of the hot water and stream cold. The warmth in the tiles is not consistent. For example, a few days ago, was the warmest it got; now, there are fewer tiles warm and those are less warm. The owner of the unit tells me this is "normal." He says it is because the hot water pipes are very close to the surface under that floor and tile conducts heat. He also says the water is hotter in winter--it was explained to me that this was not a temperature setting but the water was hotter relative to the temperature outside????? I would like to buy this unit, but do not want to buy a serious problem. Everything I can find online about this says it is not normal and indicates a leak. What can you tell me about this situation? Thanks!

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**Jerry Peck** · 12-04-2019, 10:29 AM

I suggest that you get a plumber out there to isolate your unit and do a pressure test on your units plumbing piping, not hot and cold.

If the plumbing lines hold pressure ... at least the piping in your unit aren't leaking.

Then it's time for the condo association to investigate their plumbing piping.

Do you have hydronic heat in the floor?

**Katherine Keil** · 12-04-2019, 10:49 AM

No hydronic heat in the floors. And my water pressure is excellent--does that suggest anything? I talked to the plumber that fixed the earlier leak. He suggested it could be due to shallow hot water pipes and suggested listening for running water. But he is the only person who said it could be normal. Thanks.

**Gunnar Alquist** · 12-04-2019, 11:17 AM

Originally Posted by Katherine Keil

In my condo, several months ago, there was a hot water pipe leak under the slab that heated up the tile floors. They were so hot, you could barely walk on them barefooted. The air conditioner ran 24/7 and could not keep the unit cooler than the 90s. The slab was taken up in a guest bedroom closet. The water removed. The leak repaired. The slab poured, etc. Now a couple of months later, there are some warm tiles in the master bath area. There are two sinks in that area. At times I have had only HOT water coming from both cold and hot taps. Other days, I have to let the cold water tap run a bit to get rid of the hot water and stream cold. The warmth in the tiles is not consistent. For example, a few days ago, was the warmest it got; now, there are fewer tiles warm and those are less warm. The owner of the unit tells me this is "normal." He says it is because the hot water pipes are very close to the surface under that floor and tile conducts heat.

Katherine,

In California, domestic water supply piping is placed below, and not actually embedded, in the concrete slab - except where the piping erupts through the slab on its way to a plumbing fixture (sink, shower, tub, etc.) I thought that was universal, but it may be that water supply piping in your area is embedded in the concrete. That would be something to verify locally with a plumbing contractor. Depending on the age of the home (at least around here), the hot water pipes under the slab may or may not be insulated, which will affect the amount of heat loss into the surrounding soil (gravel, sand, whatever) and up into the slab. If you did not notice warm tiles in these areas before, it is possible that there is another leak.

In the past, I have felt slab floors get warm (not hot) because of the hot water piping under the slab. However, given that the piping (presumably) is below the slab, it seems unlikely that the floor would get as hot as you describe, unless there is a significant problem.

Originally Posted by Katherine Keil

He also says the water is hotter in winter--it was explained to me that this was not a temperature setting but the water was hotter relative to the temperature outside?????

Huh??? That sounds like something made-up. Also, hot water from the cold faucet is not normal.

Originally Posted by Katherine Keil

I would like to buy this unit, but do not want to buy a serious problem. Everything I can find online about this says it is not normal and indicates a leak. What can you tell me about this situation? Thanks!

If you are seriously considering purchasing the condo, it is very important to have this fully evaluated and have it corrected. Otherwise, you could be buying into an expensive repair.

In addition to Jerry's question and recommendation, I have a few other comments and questions.

What is the age of the condo/home?
What is the supply piping material?
I also suggest you contact the homeowners' association as well as neighbors to find out if there are others in this development with the same problem?
It would be good to contact the plumbing contractor who performed the repairs in your home to get his/her thoughts/observations.
Do you know who is financially responsible for repairs of this type? This would be in the documentation held by the homeowners' association. Some things are the responsibility of the association and others belong to the individual home owner, but this varies. If this is a systemic problem, then the association might be responsible for repairs, but that could entail a "special assessment" (money from homeowners) to address problems throughout the development.

It is really, really important to follow-up before you seriously consider purchase.

**Katherine Keil** · 12-04-2019, 03:02 PM

Let me clarify. I do not believe the pipes are insulated; nor are they in the slab. They are under the slab. Also, the "hot" tiles were the result of the major leak that has been repaired. Now I have some spots that are warm...those spots at times go back to normal temperatures or seem less warm on some days. If it were a leak, it seems they would consistently be hot or even getting hotter. Why would they cool off at times?

**Gunnar Alquist** · 12-04-2019, 07:05 PM

Originally Posted by Katherine Keil

Let me clarify. I do not believe the pipes are insulated; nor are they in the slab. They are under the slab. Also, the "hot" tiles were the result of the major leak that has been repaired. Now I have some spots that are warm...those spots at times go back to normal temperatures or seem less warm on some days. If it were a leak, it seems they would consistently be hot or even getting hotter. Why would they cool off at times?

Looking back, you did say that and I misread.

Yes, the slab might get warm as a result of hot water piping. But, given your past experience (and you should not get hot water from the cold faucet), it is worth having a plumbing contractor investigate.

**Jerry Peck** · 12-04-2019, 07:36 PM

There is an installation where you could get limited hot water from a cold water faucet, but I doubt this is the case - when an AutoCirc ( http://laing-thermotech.com/plumbing...tab-literature ) is installed.

The AutoCirc is a small pump which is installed at the farthest sink from the water heater and has a sensor which turns the pump on and off. When on, the pump circulates water from the hot water side through the pump and into the cold water side and back to the water heater.

When the temperature sensor indicates 85 degree water in the hot, it turns the pump on, when the temperature sensor indicates 95 degree water in the hot, the pump turns off ... which means the water in the cold side is also 95 degrees (okay, so that is not "hot", just "warm", but it is not cold either).

Another scenario, and this was the case in one of the houses we had in South Florida, copper piping was routed through the attic, and with attics getting to 130-140 degrees in the summer, the copper piping heats up, and heats the water in them too ... and, yes, HOT water would come out of the cold water faucet for several minutes before cold water would arrive at the sink (you've likely seen where it can take 5 minutes or so to get hot water to the faucet ... that same amount of time to get cold water to the faucet applies).

I inspected a large house down in Miami many years ago (early 1990s maybe) and it took 17 minutes for hot water to get to the wet bar in the family room - yes, I times it, 17 minutes to get hot water.

The plumber had recently had another house like that and knew about the AutoCirc, that is when I found out about them, and it worked (well, there was always "warm" water at that wet bar, but hot water water only seconds away, and cold water was only seconds away too).

**Brian Hannigan** · 12-05-2019, 10:43 AM

In my brother's home you can follow the water lines that are under the slab buy the warmth of the tiles.

He has a circulation pump on the water heater so when that is running the tiles get warmer. I believe the cold line runs close to the hot and that heats up the cold water as well and takes a while for the cold water to ever get cold.

Sounds similar to your issue.

**Katherine Keil** · 12-05-2019, 11:33 AM

Thanks! So could be normal for this place and does not necessarily indicate a problem?

**Steve Kincaid** · 12-18-2019, 05:16 AM

Katherine,

Another thought. Locate your water meter for your unit (use the meter number on your water bill if you can not readily identify which meter is which). Note the position of the dial, tell tail and/or meter numbers on the meter itself. Do not use any water for the next hour or so. If there is no leak, then chances are there will be no meter movement/advancement. If there is a leak (either on the hot or cold side), there will be meter movement/advancement. You may need the association to point out the meter location if not readily accessible (such as in a locked closet).

Hope this helps.

**Jerry Peck** · 12-18-2019, 07:06 AM

Most (all?) water meters have a flow indicator, frequently a red triangle, with everything off and nothing using water (that you know of, toilets are known for leaking past the fill valves), go look for movement of the flow indicator.

It doesn't take long to see the flow indicator move if there is a leak.

**Dom D'Agostino** · 12-18-2019, 09:10 AM

Originally Posted by Jerry Peck

Most (all?) water meters have a flow indicator, frequently a red triangle...

I wish that were still true. See a lot of digital meters with no mechanical "leak indicator" in the field, you have wait for the number to move, and that may require a flashlight to activate the solar charged collector, or the LCD display goes dim.
Much easier to see the spinning triangle, or star wheel.

**Katherine Keil** · 12-22-2019, 08:01 AM

Thanks for all the posts. I am following up on suggestions. But wanted to update recent events. A day ago, the unit next door had no hot water for unknown amount of time (part of the day/evening). In checking, I had and still have cold water in the cold tap. During the outage, I had sort of warm water in the hot tap. A day later, hot water is back. Still cold in the cold tap, and many 18 inch floor tiles that were warm are cool. Some others are less warm. I think the ones directly over the hot water pipe are still warm. Wondering if this would point more toward the warm floors being caused by the hot water pipe???? What do you think?