Replies

1. 
   Danno | Jun 28, 2008 05:52am | #1

   A very similar question was just asked a day or two ago. If you do a search you should be able to find it (actually were two discussions). Those didn't ask about floor though, but there have been discussions in the past on that too. Go to top of list of discussions and click on "advanced search" and enter words like "basement floors" or "basement insulation" and the discussions shoul come up.

2. 
   RedfordHenry | Jun 28, 2008 06:31am | #2

   If you believe that you will have bulk water moving into the basement, fiberglass insulation is an exercise in futility.  Even with an interior moisture managment system like you have described, it is only a matter of time before your fiberglass is a sodden, moldy mess.

   Foam directly on the walls will prevent air borne moisture from contacting the cooler concrete walls and condensing, but as you say, it will not prevent moisture from migrating from the outside in.  In fact, NOTHING that you put on the inside of the foundation will prevent water from pushing in.

   You need to manage the water and redirect it away from the exterior of the foundation walls, or resolve yourself to a basement that will, well, always smell like a basement.

   If I had a damp basement, I wouldn't put anything other than paint, or maybe sheet vinyl, on the floor.  Anything else will be temporary at best.

1. 
   wadswob | Jun 28, 2008 07:59pm | #3

   Thanks Redford Henry.  If I put a plastic vapor barrier directly agains the foundation wall that is tucked into the perimeter drain, wouldn't that prevent outside moisture from reaching the insulation or wood on the inside?  Also, what about tile on the floor?

1. 
   dotto | Jun 28, 2008 08:52pm | #4

   Wadswob,

   First thing: address all water issues from the exterior (i.e. grading, gutters and downspouts, etc.).  I had a perimeter drain installed along three walls in my own basement.  It did not seem as effective as marketed, and now the sump pump is not even plugged in.  I paid a bunch for about 150m lf of french drain located about 8 to 10 ft from the house.  Works great. 

   Check your warranty, I was told to not secure my bottom plates to concrete floor after the perimeter drain was installed or warranty would be voided.

   The installers mentioned the poly on the foundation.  No way.  Poly will trap moisture.  I put 1" foam on first as suggested by some.  Every basement I do gets 1" foam first, 2x4 walls with R13 fg.  I am going to look into spray foam next time due to fg inability to deal with moisture.

   Here is a link to some great info on basements including the floors

   http://www.buildingscience.com/search?SearchableText=basements

   I just bid a basement that included foam over concrete with 1x sleepers then 3/4" subfloor.

   i always keep a few cans of spray foam handy when finishing basements so when we run into some air infiltration (especially at the rim), it can be plugged.Dave Otto -- Otto Construction -- PA

1. 
   wadswob | Jun 29, 2008 03:09am | #5

   Thanks Dave,

   What happened with your interior perimeter drain?  I hope a bottom plate does not void the warranty because I have already nailed one down.  As for the floor, what are you putting on top of the foam/sleepers/3/4 subfloor?  I have been told to put something down that is not a vapor barrier as the moisture will otherwise just migrate to the walls and cause mold there.

   Benj

   PS - you're not Dave Otto from Bowdoin are you?

1. 
   dotto | Jun 29, 2008 04:13pm | #6

   The interior drain did a partial job but the foundation corners were still wet.  The french drain took care of it.

   On top of the foam/sleepers/subfloor -- 3/4" engineered hardwood floors.

   I am not Dave Otto from Bowdoin

    Dave Otto -- Otto Construction -- PA