rainy season= "basement" smell & moisture on walls

Probably 80% of homeowners across the nation have had copious amounts of rainfall this year, and we also broke rainfall records here in upstate NY. But we haven't had more than 4 days without rain since the snow disappeared, and now our basement has contracted that musty old 'basement smell'.
Some facts: it's a 12-course basement in a 2-story stick-built residence.
-the bottom course (sometimes two) of block is constantly dark
-basement has a floating floor, with a gap at the edges where the block meets the concrete floor.
-never had any similar previous problems in the past.
-has 2 casement windows for ventilation & a dehumidifier (sufficient size/capacity) that's been running on high fulltime for 2 months.
-actually have some fuzzy mold starting to grow on a block
-have a sump pump in the crock that works well; but water levels in the crock are pretty normal & not rising
-the gutter drains are run away from the foundation to dry wells, and the grade is sloped away from the foundation
-no new landscaping or changes to the terrain or drainage around the house
What we need is for mother nature to relent & give us a couple dry weeks, but short of that: Looking for suggestions on how to help eliminate the musty basement odor, and try & prevent the bottom blocks being so wet all the time. (they're barely damp to touch but always dark)
I've read dozens of articles, suggestions and postings on this matter, and we simply can't afford (not at all in this economy) to dig around the exterior of the foundation to install some barrier, plus it would destroy thousands of dollars (that we also couldn't pay for) in landscaping.

 

I think the bottom blocks have water in them. They probably have mud in them as well so the dark color will always be there as they are now stained. Any cracks that water can get into will cause the water to flow through the blocks until they reach the bottom blocks.
You need to find and seal those cracks to prevent water from entering. Some may be near windows that could be leaking and the water enters the wall behind them then onto the blocks and later down to the bottom.
Depending on how finished the basement is depends on your fix for the water in the bottom blocks. You could drill 1/4 inch holes as close to the bottom of the darkest blocks to drain the water. Then it depends on if they continue to leak water after a while or not as to what needs to be done next. If it runs to the sump and gets pumped out without much mess, fine! If not you will need to have a system that causes the water to run to the sump. This could be a groove (ditch) cut in the floor near the wall, or one of the basement sentry type baseboard system that channels the water to the sump.
Best thing would be you drain the water out of the blocks and it never leaks there again. One of those things that you have to try and see what happens.

 

thanks bad,

"If it runs to the sump and gets pumped out without much mess, fine! If not you will need to have a system that causes the water to run to the sump. This could be a groove (ditch) cut in the floor near the wall, or one of the basement sentry type baseboard system that channels the water to the sump." ...we have a 'floating slab', or concrete floor that has a drainage run all the way around the basement where the bottom wall blocks meet the floor. It has small crusher run stones in it to help drain the water, and it all runs to the crock where the sump pump does well to pump it out once it gets there.
This is not what I do for a living so I'm no expert, but I checked both windows and every block seam, and they all appear intact with zero water leaking from the inside. So, from what you're saying, there must be cracks in the block somewhere on the outside...buried beneath dozens of tons of earth and landscaping that we are not excited about digging up (and can NOT afford to do).
I'm grateful for the advice, but a little apprehensive about drilling holes in the bottom of the wall blocks- doesn't that eventually affect structural integrity of that block? I'm thinking that over many years, those holes that I create will crumble and enlarge...a possibility or no?

 

Block walls that haven't been filled with concrete when installed are often a problem. Water leaks in one area and flows across the bottom and slowly seeps out. I've punched a hammer size hole and the water poured out. We were ready for the water, but not the gunk. A 1/4" test hole as suggested can easily be filled, no damage. The rest of what Ben says is right on.

That floating slab as you describe it is good in one way and bad in another. Some of the moisture you are trying to remove may be coming from there as well as the sump. Any moisture source you can block would help.

Pick up a moisture meter for basement, house and outside. By actually knowing the humidity levels and temperatures you can judge when or not to open windows or run the dehumidifier. You will also be able to see when you are making progress. Remember the humidity reading is a relative number, relative to temperature so you need to check a chart to determine what the RH will be when outside iair is pulled in. If outside temp and RH are too high to bring in, then even air leakage can be contributing to your problem. Warm air leaks out high and replacement air comes in low.

If you air condition, pressure differences may also be pulling in outside air.

Bottom line is you may need for now one or two extra dehumidifiers to get ahead of the problem. Check the water being drained out to be sure they are working and cover that sump.

Bud

 

Ok- I drilled more than a dozen holes on the bottom blocks, right at the floor level, and not one drop of water came out- seems that it's dry inside the blocks. The blocks are moist to the touch but apparently there's no water inside them. I drilled the holes in different locations around the basement but no water came out anywhere and the masonry bit was dry(no mud, sediment.moisture, etc. on it) after pushing through the block to the inside....NOW what?

 

Sounds like your dehumidifier is under sized. Look at getting a good unit and stay away from the cheap ones you will be money ahead

 

Probably at no cost, other than a bit of time, dig a hole on the uphill side of your home, go down until you meet the ground water level.
Then work out how it compares with the inside of your basement.
That dehumidifier, is it running in a sealed basement?
If the basement is not almost airtight, then you are trying to dry out the entire USA and you are just wasting money.
A lot of the water vapor you are collecting will come from outside.

 

Thank you both for helping:
airman = we bought this dehumidifier when we moved in about 3 years ago, and we have one that handles more than the square footage that we have(and it WASN'T a cheap one).
Perry = "That dehumidifier, is it running in a sealed basement?
If the basement is not almost airtight,..." -no, our basement isn't airtight...don't even know how to make it airtight, so I think you're right and we're just pulling humidity down into the basement. I tried local rental centers to find any kind of commercial-sized dehumidifier but no one carries one. I can't borrow 2 or 3 from friends/relatives, since everyone is trying to keep their own basements dry this season. I think that we just need to 'get ahead' of the humidity levels to let the basement blocks dry out before scrubbing off the mildew & stuff then applying Drylock or something similar. I thought of renting a large fan that's usually used after flooding problems, and pointing it at each wall for 1/2 day to see if it dries the blocks out. I'm REAL hesitant to try using a salamander to push heat at each wall, due to the fumes & CO2 that would create.
Am I way off on any of this?

 

The first thing to do is buy a Weather station, that has a remote sender that will record the humidity and temperature in your basement, hang the sender from the ceiling in the middle of the room, do not hang it on a wall as this will make the reading wrong.

Then you can attach the weather station to your computer and see how the relative humidity changes over ever twenty four hours. You will be able to look a graphs that will show if indeed you have a humidity problem.

If you have open windows or doors, or ventilators, holes in walls, these mean you are pulling in humidity from outside.

A de humidifier works by creating a very cold coil or plate.
The water vapor in the air is attracted to cold, so it makes its way to your dehumidifier and condenses on the coil or plate turns into water and gives you the impression that you have a humidity problem.

If the temperature in your basement is below 40f then whatever you think, you do not have a humidity problem, air that is below 40f even at 100% relative humidity is almost dry.

If on the other hand the temperature is around the 86f mark and the hydrometer says 100% relative humidity then you do have a problem.

Cold wet walls do not as a rule give off humidity.
Humidity comes from the outside via warm air or most often is produced in the home by the people living there.

Humidity comes from cooking, washing, breathing, indoor plants, fish tanks, cut flowers, wet washing, clothes drying, condensation on windows drying in the morning.

 

Perry....I think you may have put a wrong number in the line about 30f? It doesn't agree with the statement just prior.

 

Perry, the OP is having moisture on the wall problems along with a basement smell. 100% humidity anywhere down there equals a water potential and the old musty basement smell. And yes the RH near a cooler wall will be different from the center of the room, but that does not make it wrong. In fact it would be misleading to monitor just the center of a basement as the cooler walls, where the OP is having a problem, will have a higher reading. Once the readings in all areas of the basement are under control, then some clean up and see how the smell is doing.

As I said before and Perry re-stated, starting with a meter to know your RH will make it easier.

Bud

 

It is a case of a high localized water table possibly due to no means of emoving the water.

A basement is built in a hole in the ground and water will accumulate around and eventually under it even if the drainage is correct because there is not way for the water to go elsewhere without some form of deep drainage system (exterior, interior or both) and any general water tables rising will increase the amount of water and potential. On a dollar to donut bet, there is no exterior drain tile functioning to remove water.

What you are seeing is visual at the time and water also seeps and is absorbed, by the soil and building materials. If there is a wall leak, the block cores conveniently collect the water and if flows downward naturally to collect above a barrier or be absorbed. A footing can be a temporary barrier, but water can still be under the footings and slab.

If you have drain tile feeding the sump, they may be clogged, failed or otherwise not functioning. Depending on the exterior landscaping or other barriers (patio slabs, garages, step foundations, etc.) it may be cost prohibitive, so a new exterior system may be out.

The "gimmicky" trenches and surface applied plastic interior collectors are also really not a serious solution since they hide the appearance, but do NOT solve the problem at its source.

Interior drain tile is a possibility if the basement interior is open enough and you have some access to remove a little concrete and mud and get in new materials (sand and gravel, pvc pipe and some concrete). It can be a DIY job and I have done it with help from a contractor with a concrete, my 12 year old son and a few of his buddies. You can do it at your own pace and knock out the sections of old concrete as you go. It just takes some effort.

You may just be enduring a periodic phase of mother nature competing with a construction situation that was not done totally correct.

Dick

 

Vic thanks for that, I work in both Fahrenheit and Celsius as some calculations are easier in C, I wrote 30f instead of 30C. Keeping in mind that most people think in Fahrenheit I should have written 86f.

Bud, as you know mold spores are everywhere, yet the world is not covered in mold. Mold needs both food and water to live. Water he has lots of, food for the mold to grow should not be part of a basement wall, sounds like a good clean is needed, as you pointed out. Once the dirt/food is gone, the mold will die.

 

------ALL great input and much appreciated. I think that instead of waiting, I'll just start with a good cleaning of the affected blocks and see what it all looks like afterwards. Perhaps just a cleaning will remove that dark look that they have, which originally made it look like they were still retaining water. Then, seal the block with Drylock or something similar (after I plug/repair the holes that I drilled).

 

I used a bleach/water solution to scrub the block walls. It removed all of the moldy appearance and I'm thinking (hoping?) that all of the solution that washed down the walls into the trench (a good amount) killed any mold colonies there. Then I used white colored Thoroseal (with Acryl 60 mixed in) to coat the walls with a mason's brush; applied two coats and time will tell how effective that was.

I left the weep holes (that I drilled into the block) open, thinking that if water ever builds up behind the block again, then it will drain out. But maybe I just created more 'ins' for moisture to creep in by doing that...?

 

Now that you have got rid of the mold, keep in mind that mold does not grow at temperatures below 40f.
Removing the food/dirt whatever and keeping the temperature low will remove two of the three things mold needs to exist.
When you next have a load of rain, it may just run out of the holes, but that isn't a problem.

 

thanks perry; the basement is below grade/below the frost line, so the temp down there is fairly constant.
we've had some hefty rains since I did this work and no water has wept from those holes yet, and the moisture problems haven't returned. (yet)

 

I'm not trying to hijack this thread, but could you elaborate on this? How do you make a basement almost airtight?

 

40 degrees is way to cold. No dehumidifier works well in those temps. Average below grade basements are normally around 68 degrees a good dehumidifier should be able to handle this. Keep in mind that you can't purchase a good unit at the hardware store