# Wet basement walls - New Construction in Winter



## gma2rjc (Nov 21, 2008)

My son-in-law is having a house built (in Michigan) and is concerned about the basement cement walls being so wet. 

The cement work was done the first and second week of December and the house has been sealed up and heat was turned on January 15th.

They surrounded the exterior walls with 2" foam boards before back filling.

Is this much moisture common in new basement walls? 


























Also, there is a puddle of water around the well poly pipe coming up through the floor near the pressure tank. Is this common?









Thanks in advance.

Barb


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## Jackofall1 (Dec 5, 2010)

The insulation on the outside sounds perculiar to me, from all that I have read, the 2" XPS should be on the inside and the outside should have a water seal, XPS doesn't seal the wall!

http://www.buildingscience.com/documents/information-sheets/5-thermal-control/basement-insulation


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## oh'mike (Sep 18, 2009)

That looks like condensation---what's the humidity level? Is the upstairs insulated and drywalled?

New construction takes a while to dry out--check the furnace--shut down the humidifier if it has one,

Get the heat up and dry it out.

Let's see what others have to say.---Mike---


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## jomama45 (Nov 13, 2008)

That's condensation as Mike stated. The warm inside air hits the cold area's of the wall that are exposed to the weather and the humid air condensates on the surface. Looking at the pics, I'd guess that the foam either isn't tight at the top of the wall, or it is missing above grade. All of this will be compounded by the kerosene "ready heater" (non-vented combustion put's ALOT of moisture in the air) and lack of insulation upstairs, if that's the case.


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## jomama45 (Nov 13, 2008)

Jackofall1 said:


> The insulation on the outside sounds perculiar to me, from all that I have read, the 2" XPS should be on the inside and the outside should have a water seal, XPS doesn't seal the wall!
> 
> http://www.buildingscience.com/documents/information-sheets/5-thermal-control/basement-insulation


Nothing wrong with it on the outside, it's done on all new basements here. It actually helps protect the damproofing coat from damage at backfill.


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## gregzoll (Dec 25, 2006)

It is still "Green" concrete, and still curing. Pouring during Winter time, means that it will take longer for the Concrete to set. As for the outside walls, who was it that thought to put the Foam panels on the outside, and did they do any type of waterproofing? I would not be surprised that the moisture is not coming from the fact that you have a warm inside, and cold outside, and with the foundation not sealed, guess where the water is always going to come through at.

Also, it appears that the moisture follows the grade outside, but without pictures from the outside, there is no way to confirm it.


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## gma2rjc (Nov 21, 2008)

Thanks everyone. 

I think you're right about the condensation. I'll have him check the humidity level down there and tell him to turn the heat up. Would it help to run a couple fans?

The foundation was sprayed with the black stuff. I didn't look to see if the foam board goes to the top of the foundation. I have a couple pics of the outside of the house. I'll take a look at them.

The upstairs is insulated and drywalled (as of last week and I took the pictures on Saturday) The furnace is running, so I don't think they're using the kerosene heater anymore. Except for in the garage, to heat the ground before they pour the cement floor.

Thanks again.

Barb


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## oh'mike (Sep 18, 2009)

If they finished the drywall recently--there is a lot of wet mud drying along with the usual moisture from construction---Keep the heat going---DO NOT install any hardwood flooring until the humidity stabilizes.

Keep us posted--Mike--


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## Gary in WA (Mar 11, 2009)

Be glad they did. 

Basic;
Installing insulation on the exterior or "dirt side" of a basement wall has the following advantages and disadvantages:
Advantages:
* it minimizes thermal bridging and reduces heat loss through the foundation,
* it protects the damp proofing coating from damage during back-filling,
* it can serve as a capillary break to moisture intrusion,
* it protects the foundation from the effects of the freeze-thaw cycle in extreme climates,
* it reduces the potential for condensation on surfaces in the basement, and
* it reduces the loss interior space when foundation insulation is desired, and
* it conserves room area, relative to installing insulation on the interior.
Disadvantages:
* installation is expensive for an existing building unless a perimeter drainage system is also being installed,
* many exterior insulation materials are susceptible to insect infestation, and
* many contractors are unfamiliar with proper detailing procedures.
From; http://www.espenergy.com/insulating_foundations.htm
Detailed; http://www.buildingfoundation.umn.edu/FinalReportWWW/Chapter-5/5-optimum-main.htm

If you liked that…… http://www.nrc-cnrc.gc.ca/eng/ibp/irc/ctus/ctus-n36.html
Insulated those rim joists; http://www.rd.com/57548/article57548.html
Gary


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## gma2rjc (Nov 21, 2008)

Thanks for the great information Mike and Gary. I hadn't thought about the humidity level where wood flooring is concerned.

Lots of great information on those websites too. There sure is a lot to know about building a house that most people don't think of.

Barb


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## oh'mike (Sep 18, 2009)

gma2rjc said:


> . There sure is a lot to know about building a house that most people don't think of.
> 
> Barb


That's why this site is here--Hopefully we can head off some mistakes--


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## stadry (Jun 20, 2009)

*be particularly careful about the exterior grading,,, $ to donuts, the back-filling wasn't placed in compacted ' lifts ' so there will be settling of the disturbed earth back-fill,,, many local codes now require a toe drain about homes' foundations,,, unfortunately, those same codes do not usually include exterior sumps & pumps NOR drainage to daylight*


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## KhiemTran (Dec 3, 2019)

Any updates on this issue? How was the issue resolved?

I have the same problem because I have high humidity in my basement. I bought a dehumidifier and plan on spraying foam insulation at the small openings to prevent cold air from entering the basement and cause the walls to be cold and condensation build-up.

I'm considering spray foaming the walls but it can get expensive.


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