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Damp Basement? The Causes of Moisture and How to Fix it

Damp basements are a common problem in many parts of the world. They can be caused by a variety of factors, from damp soil to improper ventilation. But no matter what causes dampness in your basement, one thing is certain: it’s not healthy for you or your family! If you have damp floors and walls in your basement, don’t wait any longer to take action! This blog post will teach you how to identify the cause of dampness in your home and how to eliminate it as quickly as possible.

damp basement smell

Why is my basement damp? How to fix basement moisture

We recently had our basement finished, and everything was great for the first few months. But as we got into fall and it started to rain more, we noticed a bit of a damp basement smell. You know, that awful, musty smell of a wet basement? It turns out we have moisture in the basement. Luckily we got rid of it but there are several causes of basement moisture. Here is what you need to check and how to fix the moisture that is inside your wet basement.

What causes a damp basement?

The reason for the basement moisture smell is caused by water vapor moisture accumulating in the basement, and it has nowhere to go. Simply put, there is excess moisture in your basement either from the floors the basement walls or elsewhere. You need to identify what is causing that dampness and take steps to fix it.

Does your carpet have a lot of wet stains? It may be time to replace it; use this carpet cost calculator to see how much the new carpet will cost you.

Related: Does a Finished Basement Need a Sump Pump?


Where does basement moisture come from?

Basement moisture typically comes from one of several places.

Interior water and moisture

These are the water sources that are already inside your house. They can be from various things like a leaking furnace, humidity from showers and cooking, and so on. Even a dryer that is not properly ventilated can cause moisture to go into the air, giving a damp feel to the basement.

The most obvious culprit is a leaking water heater or a leaking flexible hose line under your sink that is going behind a wall. Ensure inspecting your water heater on top for leaks and looking around the bottom of the water heater for any leaking

Rain or water in the ground

The most common reason for moisture in a basement is water in the soil coming into your home in one capacity or another.

Standing groundwater and water that is not being drained away from the house’s subsurface drainage system is another culprit. Water will find its way into the house through cracks and other means if it isn’t drained away from the house properly. This can also happen if the water table in your area is high from excessive rain. If your sump pump has been running constantly you will want to make sure it’s not burning out or stuck, or if the discharge pipe is not blocked.

Moisture from the air outside

In the summer, you may open your windows to get a nice breeze of humid air crossing through to save money on air conditioning. But bringing in outside moist air can add more water vapors to the overall house and especially the basement.

Another way is that the warm humid air from outside can cause condensation when it hits the basement’s cooler air. This combining of two different air types can cause moisture to form.

What are the signs of a damp basement?

Some of the signs of a damp basement are:

  • Mold and mildew on the basement walls and floors
  • Moisture on the windows (which can lead to mold)
  • Water stains on the floor or walls
  • Musty smell and other damp odors
  • Wet walls
  • Paint is peeling
  • Efflorescence (white powder on wall surfaces and floors)

damp basement from hydrostatic pressure

Causes of a damp basement and how to fix them

The first thing you’re going to want to do is to identify the moisture source. To do this, you need to know the causes of dampness in the basement. These are the main causes of a wet basement and how to fix them.

Condensation on the basement walls

When warm air meets cold air, condensation forms, you may notice this in the Winter on your windows when little water beads start to form inside on the windows.

The same principle applies to your basement. Because the basement is usually cooler when hot air comes in and water vapors have contact with cool air from the basement, condensation will form on the concrete block walls causing basement dampness.

We even noticed some water on our drop ceiling tiles, which was caused by condensation from ice in the sink right above it. If you are having moisture problems in your basement and can’t tie it into a specific source, it could be the indoor air hitting the cold walls and causing your wet basement issues.

If you have a finished basement and there is moisture coming through the drywall this is likely due to holes in the vapor barrier when the basement was framed. To fix this you will need to get a specialist in to see if this is the case. 

How to fix condensation on a concrete wall

The easiest way to fix this wet basement issue is to bring in a dehumidifier and see if you can remove the excess moisture with this. If this doesn’t do the trick, there may be air leaks in the walls of your basement, and you should see about plugging them. Your concrete walls may need to be treated if they are older.

Improper grading

If the slope of the ground outside of your house isn’t properly draining away water when it rains, that water can find its way back towards the house as opposed to running off as it should.

This can cause water to come up through the concrete block foundation walls in the basement. Water can also come up through the concrete floor.  Leaks through the cracks of the concrete block foundations are caused by hydrostatic pressure in the soil.

This pressure causes cracks and excess water in the soil around your house and finds its way in through the foundation.

damp basement around windows

How to fix grading issues

Grading is the positive slope of the land around your house. It should be at an incline sloping away from your house so that any water that lands on it runs off away from the home.

If the land around your house is flat or sloping towards your house, the water will start to run towards it, causing pressure on the foundation walls around it and possibly leaking in. Standing water around the house is an indicator of poor grading.

To fix this, you need to increase the grade of the land around your house so that the water drains off correctly.

Depending on how much soil you need to bring in to fix the grade, you may need to hire someone with a bobcat to move the soil around. They will ensure proper grading with a positive slope so that you avoid dampness in your living space.

Click Here to Find a Professional


Blocked gutters and lack of downspouts

If your gutters and downspouts are clogged or not draining away from the house, you may have found the issue of moisture in your basement. That water coming off your roof will run right back down the side of your basement walls and into the ground in a larger quantity.

This is because your home’s size is displacing all that water to the edges of the house. This will cause the water to seep down into the soil and leak through the concrete walls. This can make already saturated soil worse.

This extra water can cause hydrostatic pressure and create cracks in your basement walls and push the water up through the cracks in your basement floor and concrete walls.

Add to the fact that if you are going through a wet season, the water table may be unusually high already, and combined with this with the extra water, it can start coming into the house.

How to fix blocked gutters and downspouts

To fix this issue, you want to make sure you have unclogged your gutters and that your downspouts and drain pipes are leading the water far enough away from your house.

Exterior drainage is a key part of avoiding moisture in your basement.  Inspect your gutters, drain pipe, and any other piping removing water from around the house (Big O, etc…) then remove any blockages.  This, combined with proper drainage, should ensure that the water is moved away from your house efficiently when rainfalls.

Shifted driveway and other concrete

This one is similar to your grading issues. If you have concrete around your house over time, the ground underneath it may shift, causing the concrete to lift up and slant back towards the house rather than away from it.

This means that when water comes, it will drain back towards the house and cause moisture problems.

wet basement gaps in concrete slab


How to fix shifted concrete

To fix shifted concrete, you will need to have the ground underneath the concrete get lifted up.  There are professionals that do this. It is fairly difficult for a homeowner to do given that you need the proper tools and machinery to lift up the concrete and fill it in underneath.

Click Here to Find a Specialist


Moisture coming up from the soil

If you don’t have a properly waterproofed basement, the moisture in the soil can start to push its way into the house. This can come up through the basement floor’s cracks, the cracks in the walls, or spaces in between the foundation concrete slab walls and the basement floor. This is one of the main causes of water seepage in a basement.

Related: Water coming up from the ground? Here’s how to handle wet carpet in your basement.


How to fix moisture coming up from the soil

The first thing you’ll want to do is to fill in any of the cracks in your floor or basement walls. Next, you will want to check for damp spots and see if you can find the source of water. Once you’ve found where it’s coming from, then you’ll want to remove any obstructions that are trapping moisture or block airflow which could be causing your damp basement in the first place.

Then it’s time to install a dehumidifier near this damp spot. This will help to draw out the dampness and moisture in the air which should reduce any damp basement symptoms you might be experiencing

If this is not enough, then it’s time for a call with your local expert or plumber who can come take care of damp basement issues more than just sealing up cracks!


Improperly vented clothes dryer

If you have an unvented dryer in your basement (meaning it is not being vented to the outside), then all the moisture from the wet clothing will go back into the house. This can be a source of dampness throughout the basement and even throughout the rest of the house.


How to fix an improperly vented dryer

The easiest way to fix an improperly vented dryer is to get a dryer venting kit attached to the exhaust of the dryer and have it properly ventilated to the outside. You can hire a handyperson to do this, or you can do it yourself if you are fairly handy.


Leaking pipes

A water leak is never something you want to deal with, but it does happen. The moisture in your basement has come on suddenly. It’s a good idea to start checking around to make sure that there isn’t a specific spot that the moisture is coming from.

damp basement standing water

How to fix leaking pipes

For fixing leaking pipes, you’ll need to contact a plumber and have them source the issue to make sure that it is just a single instance and not an issue throughout the house.


Click Here to Find a Professional 


Broken or lack of weeping tile/drain tile

If you have a newer home, you likely have weeping tile at the bottom of your house’s foundation. This is code in most places. However,  if you have an older home, it could be that you do not have a weeping tile to take the water in the soil and move it away from the house. When the water has no place to go, it will cause it to come back into the house.


How to fix weeping tile issues

It is difficult to tell if you have weeping tile issues or drain tile issues. If you have gone through the rest of this list and have determined that this must be the cause, the best to contact a professional to come in and take a look at your weeping tiles and see if that is the issue.

Click Here to Find a Professional 


Broken sump pump

Your sump pump is designed to take the water I’m around the house and push it further away so that you relieve the water in the soil and displace it somewhere further away from the house so it can’t cause any damage.

A broken pump can also cause damage and lead to flooding in the basement. Check your sump pump regularly to make sure that it is properly functioning. It is also a good idea to have a backup sump pump or a battery-operated one if the power fails.


How to fix a broken sump pump

The steps for doing this are more than this article’s scope, but you can fix a sump pump. More than likely, you will need to have it replaced. Often what happens with pumps is that they get stuck open, and the motor burns out.

To prevent this from happening, it’s a good idea to perform regular sump pump maintenance and test it every Spring to make sure it is properly working.

Related: Sump Pump Problems: How To Fix Them


Damp Basement water coming in from wallsMuch like your dryer not being properly vented to the outside, condensation can occur when hot water vapors in the air from elsewhere combines with the cool air of a basement and cause moisture resulting in condensation on the walls.


How to fix condensation issues

The easiest way to fix condensation issues in your basement is to exhaust the air in the basement to the outside. If you have the ability to do so, you can use an exhaust fan to vent out excess moisture in the basement.

Another way would be to get a dehumidifier and use it regularly to draw out the moisture in the air and then dispose of the extra water.


Standing water

We all know we don’t want to have water damage on our hardwood floors, but in a basement where there is often carpet, this gets harder to detect.

You will want to regularly walk around your basement and see if there is any moisture on your floors pooling anywhere. This can be a sign of a leak from one of several sources and is a likely culprit of your damp basement (a hint may be if you have had low hot water pressure, it could be leaking).


How to fix standing water issues in your basement

Standing water in your basement is likely from a source close by to determine if the water is trickling from another location and pulling in the area that you have found it or if it is coming from somewhere immediately in the vicinity of the water. Once you have found where the water issue is coming from, you can then better deal with it.


Final thoughts on moisture sources in damp basements

While moisture in a basement it’s not something to panic over. Take some time to identify what is causing the moisture. Then see what steps you can take to correct it, and you will be good to go.


Click Here to Find a Professional 


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