# condensation forming in new home



## chrisd0608 (Jan 21, 2011)

We finished a $3 million custom home about 3 months ago. We started the geothermal system over 7 months ago with no issues like this until now.

Today, my client called me and said there was water dripping down the walls in on of his downstairs 1/2 baths.

The bath room is located in between the laundry room and a hallway to the exterior and it is the only room with condensation forming on the ceiling. 

There is an exhaust fan in the ceiling and one supply grill in the floor. The door remains open and there is a return within 4' from the door in the hall way. 

The floors are insulated with 1'' of closed cell foam, exterior walls are 5.5'' of open cell foam, interior walls are r 13, the trusses between the 1st and 2nd floor have r38, the rafters have 8" of open cell foam.

My engineer and fellow contractors are all a bit stumped... 

Anyone have any ideas?


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## hdavis (Feb 14, 2012)

First I'd check to see if air from the dryer vent is getting trapped under the eaves and pushed back into the bath vent, or a similar scenario.


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## Red Adobe (Jul 26, 2008)

Where are you talking about........in the north things are way different ventalation wise then in the sunny SouthWest

Wheres the plumbing runs? With foam its possibly a leak in the vacintity thats traveled from above


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## chrisd0608 (Jan 21, 2011)

Dryer vent goes under the house and in the opposite direction.

We are in NC. There is plumbing above, but one room over (directly above the laundry room beside of the 1/2 bath). There is a conditioned attic space directly above the 1/2 bath, no sign of water intrusion. or leaking pipes (back of wall is open so plumbing is visible) Keep in mind, this is an interior room, no foam insulation within 5'-7' of the room. 

The ceiling "drips" from random points, the water is not located in any central location and it appears to be on the surface and not bleeding through the Sheetrock and paint.

I will also add that I spent an hour and a half there today trouble shooting along with my plumber and HVAC guys. We were unable to make the ceiling drip. The owner came home tonight and the water was back....


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## tyb525 (Feb 26, 2013)

Sounds like HO likes long, hot showers, and maybe doesn't use the exhaust fan like they should. Also should be letting it run for like 15 minutes afterwards...A house as airtight as that won't lose moisture any other way besides the exhaust fan.


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## chrisd0608 (Jan 21, 2011)

tyb525 said:


> Sounds like HO likes long, hot showers, and maybe doesn't use the exhaust fan like they should. Also should be letting it run for like 15 minutes afterwards...A house as airtight as that won't lose moisture any other way besides the exhaust fan.


No shower, it is a 1/2 bath.


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## tyb525 (Feb 26, 2013)

Duh, sorry, didn't catch that.


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## Metro M & L (Jun 3, 2009)

3 million dollar home? Sounds like the client likes taking long hot showers on the bidet and they don't use the ventilation like they should...:laughing:


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## Calidecks (Nov 19, 2011)

If there's a window or door open when the AC is running it can cause condensation running down the walls from the registers


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## hdavis (Feb 14, 2012)

Bring a non-contact thermometer and borrow a moisture meter if you don't have one. 

Is the ceiling getting cooled off?
Is the water just on the surface, or does it go further?

The dripping only in certain spots is pretty odd. You can get condensation on drywall screw head locations - they'll be a local cold spot if it's cold on the other side of the drwall.

My next guess would be it's a tight house, and they're kicking something on or opening something on an upper level that results in outside moist air being drawn back through the vent (Negative pressure either through stack effect, or power venting, possibly both).


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## hdavis (Feb 14, 2012)

OK, so the homeowner comes home and it starts dripping. Does it do it when he isn't home? Is it the same general time? I'd ask about his routine when he comes home, and check program set points, etc.

More clues...


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## beenthere (Mar 5, 2009)

Is there a large exhaust hood in the kitchen? What type of fresh air system does the house have?


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## flashheatingand (May 3, 2008)

chrisd0608 said:


> Dryer vent goes under the house and in the opposite direction.
> 
> We are in NC. There is plumbing above, but one room over (directly above the laundry room beside of the 1/2 bath). There is a conditioned attic space directly above the 1/2 bath, no sign of water intrusion. or leaking pipes (back of wall is open so plumbing is visible) Keep in mind, this is an interior room, no foam insulation within 5'-7' of the room.
> 
> ....


Could you drill a slight hole in the ceiling and stick a either a meat thermometer or a krobe thermometer to take a temp reading of the space above the ceiling? Just wondering if the condensation is happening due to some air infiltration in the ceiling cavity, and the td occurs due to too much cool air supply in the bathroom. 

Or, you could block the supply air to the room in question (1/2 bath) to see if the problem persists or not.


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## pappagor (Jan 29, 2008)

chrisd0608 said:


> We finished a $3 million custom home about 3 months ago. We started the geothermal system over 7 months ago with no issues like this until now.
> 
> Today, my client called me and said there was water dripping down the walls in on of his downstairs 1/2 baths.
> 
> ...


update did you find the problem


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## mrcharles (Sep 27, 2011)

Is there Geothermal condenser piping anywhere in the vicinity? That stuff needs to be have sealed insulation on it... not just black foam pipe wrap. The system might be under more load now and producing more condensate? Just a thought


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## brunothedog (Sep 8, 2013)

houses have to breath, airtight houses are a like a petri dish filled with bacteria.


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## MTN REMODEL LLC (Sep 3, 2010)

brunothedog said:


> houses have to breath, airtight houses are a like a petri dish filled with bacteria.


How true ^^^^^^^^^^^^^^^^^^....

I've never fully comprehended the economics of insulating the house airtight... and putting in an exchange system.


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## SLSTech (Sep 13, 2008)

It is not about economics - it is about health & safety though I got to say the standards are to high for most "normal" buildings
http://blog.sls-construction.com/2013/bs4d-ventilation-strategies


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## MTN REMODEL LLC (Sep 3, 2010)

SLSTech said:


> It is not about economics - it is about health & safety though I got to say the standards are to high for most "normal" buildings
> http://blog.sls-construction.com/2013/bs4d-ventilation-strategies




SLS.... I whole heartedley agree a home should not be airtight with no introduction of fresh air change.

I just don't comprehend us building an airtight skin (with attendent costs) and then an air exchange system (with attendent costs).

I actually thought the issue ever arose when in the 1980's with the introduction of energy concerns/conservation.... we started building airtight (in response to energy conservation)..... and then realized/argued that we need fresh air exchange.

What was wrong with non-airtight construction, ambiant air exchange, and natural air introduction.

Is it just that we are looking for a exact control/decimal point level of control, with regard to fresh air exchanges.

Just seems there may be some irony here.


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## beenthere (Mar 5, 2009)

> What was wrong with non-airtight construction, ambiant air exchange, and natural air introduction.


Often it was too much. On the mildest of days, it wasn't enough. 
A tightly constructed house with an ERV has a controlled rate of exchange. Doesn't dry out the air in inter as much, nor add as much cooling load in the summer.


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## TheLoneRanger (Oct 11, 2013)

Exactly. ^^^^ It's all about energy control. Now you can have your IAQ comforts as well.


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## MTN REMODEL LLC (Sep 3, 2010)

Sorry..... I recognize what your saying, but I don't believe any systems have that level of control, or that we really know what that level of control should be.

I think we are being sold somewhat a pile of technological crap.... at least in residential.... for X's sake... open a window.


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## TheLoneRanger (Oct 11, 2013)

MTN REMODEL LLC said:


> Sorry..... I recognize what your saying, but I don't believe any systems have that level of control, or that we really know what that level of control should be.
> 
> I think we are being sold somewhat a pile of technological crap.... at least in residential.... for X's sake... open a window.


Does the perfect envelope exist in average production homes? No! However, I great level of control can be achieved easily. Opening a window, when outside conditions are not right, is the worst thing you can do. The vast majority of times, those conditions don't exist. An extreme amount of energy is wasted and IAQ suffers a major blow. Why did we do it for so long? Energy was thought to be abundant and no one realized the air quality way affected in such a way. It seems so illogical today but, now we have a much better grasp on the science or we just started to give a sh*t.


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## flashheatingand (May 3, 2008)

The more we know, the less we know.


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## zigo22 (Nov 7, 2013)

*condensation*

For what it's worth,I'll tell you what happened with a rental property i own,
tenants started complaining about water on the ceilings when it was really cold out side,i pulled my hair out trying to fix this problem,put more isolation in the eves,figuring the cold air was blowing in and chilling the ceilings,then i did blown in in the the attic,it helped but were still getting moisture.I started noticing the one year i was getting a lot of ice damning,
on this porch that was closed in, i pulled down a piece of ceiling and found the problem,the add-on was just isolated with r-19,and was put up against the 6"roof Joyce,and no ventilation in where the addition was added down half of the one side of the house.the lack of ventilation in 25% of the roof was causing condensation in most of the rooms.
i ripped the ceiling down,put up ventilated rain drip(there wasn't a Soffit in the add-on)put up the foam vents under the isolation,then a vaulted drop ceiling with a 2" air gap between the drop and the rafters,
and no problems since.I had 3 different contractors and an isolation expert come out and didn't figure it out,I pretty much found it by accident.Ventilation is one the most over looked reasons for condensation,Have to let the house breath or you'll pay dearly for it down the road.


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## tyb525 (Feb 26, 2013)

> Opening a window, when outside conditions are not right, is the worst thing you can do. The vast majority of times, those conditions don't exist. An extreme amount of energy is wasted and IAQ suffers a major blow. Why did we do it for so long? Energy was thought to be abundant and no one realized the air quality way affected in such a way.


Indoor air quality? When did our air stop coming from outside? Ever heard of sick buildings? Those definitely weren't caused by open windows.


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## TheLoneRanger (Oct 11, 2013)

tyb525 said:


> Indoor air quality? When did our air stop coming from outside? Ever heard of sick buildings? Those definitely weren't caused by open windows.


Is this multiple trick questions? If not, here are the responses.

IAQ? The quality of air indoors.

When did our air stop coming from outside? It never has.

Ever heard of sick buildings? Absolutely. The cause is from poor indoor air quality.

Those definitely weren't caused by open windows. Actually, depending on the geographical location, a very large number of cases are.


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## flashheatingand (May 3, 2008)

Could you clump the problematic "open window" cases in the similar geographic locations?

For the most part, I am an open window guy, but would like to know if there were some similar conditions.


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## tyb525 (Feb 26, 2013)

I'm just having a hard time believing having windows open causes problems with IAQ, unless the air is more polluted than normal, or it is raining...


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## beenthere (Mar 5, 2009)

In some cities, open windows leaves pollutants come in before the air/wind has a chance to dilute them much.


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## tyb525 (Feb 26, 2013)

I guess I'm glad I live way out in the country then


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