Replies

1. 
   DanH | Jul 17, 2012 07:34am | #1

   I would guess the smell got into the floor somehow (an incontinent dog or sewage leaking from below, eg) and the coating was added to try to cover it up (so to speak).  I'd try to figure out the source of the smell before going much further.

2. 
   renosteinke | Jul 17, 2012 11:55am | #2

   "There are NO

   "There are NO short-cuts."

   Repeat it untill it catches.

   You're in trouble because someone took a shortcut. Now - in the interests of full disclosure - I must point out that my advice here differs from what most 'experts' will tell you.

   The basic error - and the reason for the coating you found - is the belief thatyou can keep moisture out of a basement. You can't. All that 'sealing' attempts do is trap moisture in place, where it feeds mold, and mold stinks. It's that simple.

   No, what you need to do is let the moisture out. Preferably, faster than it can enter.

   Step #1 is to have a true, flat floor, with perhaps a slight slope toward the drain. There are various porous materials for this. For example, gypsum concrete. You want porous, because concrete is porous. Use rubber and you get .... what you've already got.

   Step #2 is VENTILATION. Moisture can come from the earth or from the air. It will condense in the basement if you allow it to sit there. Instead, you need a generous flow of warmer, conditioned air flowing through the basement. Basement remodels almost always neglect to do this.

   Thus, I'd say 'no' to laying plastic sheeting down, or making any other sort of vapor barrier. As I see it, the foam panels will make a vapor barrier anyway - and you never want to have two vapor barriers. I'd even leave a generous gap (1/2") around the walls and 1/8" between the foam panels and the wood framing.

   Speaking of wood.... got termites? I might just lay the panels on the floor, and the plywood atop them, without and wood under the plywood at all - except for the perimeter. There, I'd use the best pressure-treated stuff I could get. I'd also SCREW it down, no glue, so it can be removed if there's a flood. Remove-dry-replace. Let the floor 'flex' a bit; that will help pump air through the space under the floor as you walk across it.

   For similar reasons, I'd space the finished walls off the foundation walls just a bit.

1. 
   DanH | Jul 17, 2012 06:56pm | #4

   You forgot to mention drain tiles.  I'd strongly advise considering tiling under the floor, or digging around the exterior of the foundation and installing tile.

3. 
   renosteinke | Jul 17, 2012 11:56am | #3

   Remove using a roto-hammer with a wide chisel bit.

4. 
   k1c | Jul 18, 2012 09:38am | #5

   I don't know any basement that doesn't smell.  I am in NJ and even this year of drought and heat, the smell came back for the summer.  I run a dehumidifier and have supply and return connections for a/c and heat.

   Start with outside.  Does rain run off toward the house?  You need to make sure (even post holes and gutter drains) that any source of water runs positively away from the house.

   Musty smell is most likely from mold.  Mold feeds off anything organic, anything that is building material and including dust.  I used closed cell insulation sheets to enclose the foundation wall, closing gaps with expanding spray foam.  The wall was finished paperless sheetrock.  The smell was cut to more than half.

   Removing self level compound is a waste of effort.  What you may think is a pristine surface is already full of mold spores.  Ceramic tile laid with thinset will have least organic material. 

1. 
   DanH | Jul 18, 2012 08:10pm | #6

   I've been in many basements that didn't smell musty.

5. 
   Scott | Jul 19, 2012 12:01am | #7

   Yeah, what the other guys say.

   I've owned crappy houses with crappy drainage and I've built a house with which I tried to "do it right". Like yours, our house it on a steeply sloped lot with the rear of the house backfilled. The front of the basement is exposed to daylight.

   The first plan of attack is to have all ground surfaces sloped AWAY from the house, on ALL sides. This can make a huge difference. Otherwise you can have water pooling against the foundation walls. I've never seen any water emerge from our permimeter drains. I've even sprinkled dust in the pipes to see if anything ever flows. Nothing; it's all handled by the slope of the surface drainage, but your mileage may vary.

   The next issues have been addressed by other posters....drain tile, drain tile, drain tile. You need to direct water away from the foundation. If you end up excavating around the perimeter think about some of the "drainage barrier" products (perforated plastic mats laid against the foundation). They work well.

   And don't skimp on the drain rock, felt, and pipe. I'd use ridgid perforated PVC rather than the flexible stuff, and be careful to bed it properly so there are no low spots in the drainage plane.

   All of this is common sense to anyone who installs this stuff professionally but of course there are plenty of hacks out there who will do it for cheap and screw it up.

   Good luck.

6. 
   rusty52 | Jul 20, 2012 01:10pm | #8

   I think that is exactly the problem.  Whoever did the work, did a hack job and what I have now is slab with cement based self leveler, anywhere from 1/4" to 2+" thick, and then on top of that they used a gypsum based product (I assume because it's white and looks like drywall) On top of that they coated it with rubber. The rubber gypsum combo seems to have trapped all the mold and mildew smell. 

   I have a concrete grinder coming today to get rid of the rubber, and I am hoping they can get the top level of the gypsum as well.  

   I bought the dehumidifier, so I will use that, although I have to say the floor is bone dry now.

   Next question will be if I go the 1" EPS on floor with two layers of 1/2" ply and then a laminate floor on that should I try to seal it all up with a vapor barrier underneath, i.e.  the delta fl dimple mat.  I was reading over at this old house a contractor who says he has had to remove a bunch of the delta-FL in multiple houses as mold builds up below it.  There seems to be a lot of conflicting info out there on vapor barrier vs none.  This is where I need the experience vs. the knowledge.

   thanks!

1. 
   DanH | Jul 21, 2012 07:03am | #9

   I'm going to point out (again) that if they needed to level 2"+ then there's been some major subsidence in the floor, indicative of poor soil conditions and/or serious water infiltration.

7. 
   rusty52 | Jul 25, 2012 02:23am | #10

   So I ended up chipping out all the self leveling compound and took the floor down to the slab.  Smell is gone just like the SLC, what a nightmare that was.  There was 5 layers of the stuff in some places..  The previous tenants just lived with the smell the last five years. 

   Now that the SLC is out I need to level the floor.  If I shoot a laser line from the door into the room the corners are 6", 4", 3" and 2" below that line, so XPS then some wood framing 16" OC on top then 3/4 plywood? or 2 1/2" layers?  I plan on floating a laminate floor on top of it all.

   thanks.

1. 
   calvin | Jul 27, 2012 07:09am | #11

   rusty

   A laminate floor needs flat.

   Level would be great, but flat is key.