Replies

1. 
   rez | Aug 01, 2007 08:36pm | #1

   Greetings dave,

   As a first time poster Welcome to Breaktime. 

   This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.

   Perhaps it will catch someone's attention that can help you with advice.

   Cheers

   The mass of men lead lives of quiet desperation. What is called resignation is confirmed desperation. From the desperate city you go into the desperate country, and have to console yourself with the bravery of minks and muskrats. A stereotyped but unconscious despair is concealed even under what are called the games and amusements of mankind. There is no play in them, for this comes after work. But it is a characteristic of wisdom not to do desperate things.

2. 
   Piffin | Aug 01, 2007 11:26pm | #2

   Inside EPS is fine, but I prefer XPS exterior.

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

3. 
   MrEnergy | Aug 08, 2007 12:29am | #3

   EPS - expanded polystyrene - 'bead' board. Less consistent, tends to 'crumble' more.

   XPS - Extruded polystyrene - blue, pink, or grey board. - higher R-value per inch. Higher cost (there's a newsflash). More 'durable' to use, handle, cut, and install. Smaller air pockets, hence better R-value per inch.

   Both are the same plastic. Just different methods of manufacturing. Both should be resistant to moisture/water. XPS you can cut accurately w/ saws (including your table saw). Less messy to cut. Can cut accurately w/ e.g. a table saw.

   XPS may be cheaper per R-value (R-5 per inch). I think EPS is like R-3.8 per inch or something like that.

   You get more R-value for the cavity you fill and better consistency and workability w/ the XPS ... personal opinion.

4. 
   mike_maines | Aug 08, 2007 01:41am | #4

   EPS has a higher perm rating than XPS.  In other words it allows more water vapor to pass through.  That could be a good thing or a bad thing, depending on the situation.

   If this is a remodel I assume you're adding the foam to the inside wall?  How dry is the basement?  Do you have a humidity control system?  What kind of studs will you be using?  What kind of wall surface will you have?

1. 
   gmcdave | Aug 08, 2007 05:11pm | #5

   Yes, remodel. Old house (bungalow), built in 1923, Seattle area. There is no water in the basement but it is currently unheated. It stinks (that musty basement smell). That's what I am trying to fix. No humidity control. All walls are concrete. Was planning on using 2 inch foam on concrete and then a regular fir stud wall.

   Thanks!

   Edited 8/8/2007 10:12 am ET by gmcdave

1. 
   AzDiscDog | Aug 08, 2007 06:16pm | #6

   Hi Dave,A friendly $0.02 worth of advice -- do a double check and look for moisture again. That musty smell comes from mold. Mold grows well with moisture. That having been said, I realize you're in Seattle (not known for it's arid conditions) so you may have the musty smell due to ambient conditions and a poor seal to the basement.Glen

1. 
   gmcdave | Aug 08, 2007 08:41pm | #7

   Thank you. I think many basements in this part of the country have that musty smell but mine seems much worse. But there is no standing water. The basement has been relatively warm all summer. What do you mean by "poor seal"? Do you mean air seal? Or do you mean the concrete walls are wicking moisture?

1. 
   AzDiscDog | Aug 08, 2007 08:56pm | #8

   Possibly both. :-)Some culprits I found in my basement:
   Sill plate had gaps between it & basement walls
   Basement windows had gaps around them
   Old dryer exhaust vent was basically an open connection to the outside.
   Holes drilled for systems (electrical, heating, cooling, etc...) were not properly sealed.All of them "little things" by themselves, but they added up to quite a bit of space to allow exchanges with the outside air.It would be worth checking to see if the walls / floors are wicking moisture, too. Use Duct tape to tape 12" squares of plastic in various places. Check them at 24 hours and at 1 week. Presence of moisture would be bad. :-)Glen

2. 
   mike_maines | Aug 09, 2007 12:53am | #9

   The basement has been relatively warm all summer

   Has it been warm because you leave windows/doors open for it to "air out?"

   Having a good seal means that warm, moist air is not getting into your naturally cool basement, where it condenses on any solid surfaces and invites mold and mildew.

   Ideally your basement would be conditioned, meaning the temperature and relative humidity could be maintained at levels that prevent mold growth.

   Check out http://www.buildingscience.com for lots of good information.