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StevenC 06-15-2009 10:24 AM

Damp cellar?
When my house was built back in 1940 they dug a cellar and poured 1/2 thick concrete on the floor and walls. Since then, most of the concrete has broken off the walls into pieces but the floor is still in one piece. The house had water issues when I bought it so the first thing I did was sloped the foundation 5' away on the back of the house which is the high side of the foundation. The dirt walls still show dampness and even the concrete floor is absorbing some of the water coming through the ground.

Will it ever dry out and how does water seep through the dirt if the ground outside is sloped away? What else can I do to keep it dry?

Any advice is much appreciated,

glennjanie 06-15-2009 07:35 PM

Welcome Steven:
Water under the ground is routed by clay or stone formations which cause springs. Your cellar would need a lot of ventilation or a dehumidifier to dry out.

StevenC 06-16-2009 09:48 PM

Well that makes sense then. Under the top soil is all red clay.


CyFree 06-17-2009 08:23 AM

Hi Steven...
If I understood correctly, the walls of the basement are now all dirt and the only concrete left is over the floor? In that case a dehumidifier will hardly handle the job, as the water is consistently seeping through the dirt and concrete. (Not to mention the cost of running a dehumidifier under these conditions)
And unless you live in a cold and dry climate year round, no amount of ventilation, at any given season, will ever dry the basement enough to keep it from developing moisture related problems (mold, rotten floor joists, termites, etc)
Depending on how big is your basement, I would suggest you consider treating it as we would a conventional dirt crawl space.
The sloping helps, but you might benefit from installing a drainage system and a sump pump. Then line the dirt walls with a thick and sturdy 20mil vapor barrier (about as sturdy as a pool liner) and depending on the size of the basement, line the concrete floor as well.This will keep the water that evaporates from the ground, out of your basement, while the drain tile collects the rain and spring waters and the sump pump discharges it as far as possible from the house.
You can then run a dehumidifier, to completely dry the basement and keep it dry.
When applied to crawl spaces, encapsulation can make the whole houst at least 18% more energy efficient.
I believe that you might be pleasantly surprised with the energy savings if you control the moisture in your basement as well, even running a dehumidifier.(Make sure you pick an Energy Star rated model)
Extra caution if you run combustion appliances (furnaces, water heater) in the basement; in that case you will need a professional basement or crawl space specialist to do the job. Those appliances need a consistent supply of fresh air to work and you can't risk depressurizing the basement with such appliances in it.

StevenC 06-17-2009 09:36 AM

Yes, that's correct. Floor is still concrete but the walls are dirt. There's a sump pump already down there. I've been running a dehumidifier but like you said it's not doing much. Where could I find 20mil at and if I were to install a 20mil vapor barrier doesn't this create moisture underneath causing more problems? And where would I need to install a drain tile at specifically?


CyFree 06-18-2009 03:03 PM

I am not allowed to indicate companies or products in this forum, so I will recommend you to "google" crawl space liner or crawl space vapor barrier to locate suppliers.

Drain tiles are usually installed either outside the basement, by the footing or internally, along the perimeter of the basement walls, which I believe to be your best option.
I gave it some thought and besides the liner, there are uninsulated and waterproof basement wall panels, a bit more rigid that the poly sheets, that might suit you well.

Should you line with poly, or use a wall system to line the basement walls, an internal drain tile will collect any moisture buildup behind the vapor barrier and divert it to the sump pump.

Optionally, since your concrete floor is apparently intact, if you cover the walls and install the drain tile, you can install plastic basement floor tiles that will allow the slab underneath to breathe and the moisture to evaporate.

Please understand that those are simply suggestions I am giving you, based on products and methods that I know to be currently available, without ever examining the place to see exactly how big is the problem.

It might be a good idea to call a few waterproofing or crawl space repair companies offering such systems and ask for a free consultation (most reputable companies offer them). This way you will know all your options and be able to choose the one that makes more sense to you.

StevenC 06-21-2009 10:56 PM

Thanks for the advice. I found a company locally who specializes on this. I was talking to a friend of mine and he suggested adding ventilation in the block too, since there is none right now. But I found some people disagree with ventilation? Also, I'm considering adding drain tile to the exterior perimeter. Will it still be effective if the foundation of the house is only 3'-3.5' below the outside dirt level? Unlike a full basement.

CyFree 06-22-2009 07:14 AM

Ventilation is not a good idea indeed and I will try to explain why. Because of the way it is built, your basement harvest temperature from the ground and the above floors, so the temperature in there is pretty constant and a bit on the cool side (usually around low to mid 60's). Now let's think a nice summer day, say 85 degrees with around 75% humidity.
You let that hot air into the cooler 62 degrees basement.
For each degree it cools the humidity level in the air increases 2.2%, so that 85 degrees air getting cooled around 20 degrees will cause the humidity in the air to rise a bit above 40%. Add that to the 75% that was already present in the air and you will get a number way above 100%.
Since the air can't hold more that 100% percent, it will give up some moisture. And how? Condensation.
Water will condensate in every surface ans that is particularly troublesome for your floor joists and wood structures, as wood absorbs moisture and grows mold.
Of course no all days are nice summers, but depending on where you live, there is a big chance that from spring to fall you will have several days in which the outside air would increase the RH in the basement above 60%, thus creating the ideal conditions for mold and dry rot.
During winter, of course you do not have to worry about moisture and condensation, and the conditions are inverse and the basement should dry. However, who wants the cold drafts, the cold floor, frozen pipes and the energy penalties of allowing cold air in the basement?

StevenC 07-12-2009 06:40 PM

Additional information: over the years trees have grown to enormous size within close proximity 20-40ft from the house with their root systems pentrating the cellar walls of the house. Can these root systems be the reason water is finding their way into the cellar even with the dirt sloped away from the house?

Any suggestions on dealing with this issue?

Also, to Cyfree. I've noticed all of the new houses built in my area have vents in the foundation walls thru the crawl spaces. I live in Tn

CyFree 07-13-2009 08:28 AM

Hi Steve..

Some building codes in US still insist in recommending crawl space vents, and that might be the case in TN, which is why you see the new homes being built that way.

Some codes actually forbid closed vents.

However, slowly, things are changing. Many codes now allow for closed vents, provided the space is conditioned.

The Energy Efficiency and Renewable Energy division of the U.S. Department of Energy recommends encapsulation as best building practice in its Building America initiative, as do Advanced Energy, Habitat for Humanity and Building Science Corp.

The concept is relatively new and still not widespread, but slowly, things are changing as more and more studies on its effectiveness are being published.

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