My house is on a slab (no basement, no crawl space) and every summer when it gets hot and humid i am getting a ground/soil smell in our living room. First i was blaming it on the absence of the basement but now realized that i only get this smell in one room. The only difference about that room is that it has a lawn along one wall and a flower bed along another.

Can that be a reason? Maybe i should pave a foot of space along that wall.

What else can cause it?

  • Can you smell it with the windows closed?
    – aphoria
    Commented Jul 28, 2010 at 14:48
  • Yes, I can. The windows are closed most of the time.
    – Vitalik
    Commented Jul 28, 2010 at 15:52
  • 1
    Is the ground around the area pitched away from the house? I'm not familiar with building on a slab, but I would suspect if there is not proper drainage water could be penetrating the walls bringing soil with it. This problem may be compounded by watering the flowers, if the flower bed is not draining away from the house but into it.
    – Tester101
    Commented Jul 28, 2010 at 16:04
  • I agree with @Tester01... probably has something to do with poor drainage in that area. Possibly water buildup under the slab at that location. Commented Jul 28, 2010 at 19:32
  • What type of flooring is in the affected area? A crack in the slab could allow earthy odors to rise up into the house. Or water wicking up through the concrete could be damaging the flooring if it was not properly installed, could you be mistaking the smell of mold/mildew as soil?
    – Tester101
    Commented Jul 29, 2010 at 1:53

2 Answers 2


This is very likely a drainage issue. I would check the following things:

  1. Does water drain away from the house near this room?
  2. Are plants growing right up next to the foundation?

You might want to put a buffer of 10" of rock (4-6" deep) next to the house.

Since the house has vinyl siding you need to peek under the siding and see if you have moisture collecting under the siding. Spray the side of the house gently with water or go out after a rain and pull back some of your siding and check for water seepage. The smell could be the result of smells outside but it could be moisture in the walls.

The cinder blocks can also be an issue. Concrete holds a surprising amount of moisture. In addition to the things mentioned above, you likely would benefit from a dehumidifier in this room. Check the humidity with a cheap humidity tester and if the room is over 65% humidity you should consider dehumidifying.

  • The plants and the grass is right next to the house including the north side of the house that almost never sees any sun. 10" wide? if so how deep? Will the buffer help to water to drain away? honestly i never noticed any water concentration near the house after the rain. Siding is vinyl panels.
    – Vitalik
    Commented Jul 28, 2010 at 20:08
  • And the walls are cinder blocks. Can moisture go through cinder blocks?
    – Vitalik
    Commented Jul 28, 2010 at 20:31
  • The drainage and the rock buffer are sort of different issues. Drainage issues will result in swampy rot next to your house. That stinks and can easily work its way through the panels. Plants against the house cause wicking of moisture from the plant onto the siding. So the siding ends up being wet for a long time after each rain. And since you mention this side does not get sun, I bet it dries slowly. I added depth to my answer as well as checking on moisture under your siding.
    – JD Long
    Commented Jul 28, 2010 at 20:32

Improper drainage can cause water to either enter directly into the house (between the slab and cinder block), or build up under the slab.

The water can also be entering the cavity of the cinder block through a small crack, bringing soil and other debris along with it. When the water evaporates it is possible that it is carrying the odor with it, either up through the cinder block and into the house, or through another crack in the interior of the house. In a case like this you will most likely not see any signs of water in the house, but it could very well be whats causing the smell.

Make sure the land around the house is properly graded away from the house, and possibly install a French drain especially if the land is graded towards the house. The drain can be used to divert water safely away from the house, and can usually be installed by a DoItYourselfer.

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