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How To Correctly Dry Out A Wet Crawl Space?

Sam Smith Foundation Repair Consultant

a crawl space with air mover to dry out the structure

Are you curious about how to go about drying a wet crawl space?

Great, you’re in the right place!

In this guide, we explain all you need to know about keeping your crawl space dry, including:

  • What Causes Water In A Crawl Space?
  • How Do You Clean Up A Flooded Crawl Space?
  • How Do You Dry Out Your Crawl Space?
  • How Do You Prevent Future Flooding In Crawl Spaces?
  • How Do You Prevent Moisture In Your Crawl Space?

In most homes, crawl spaces offer the right balance between slab and basement foundations.

They allow you access to vital parts of your home without the need for more expensive basements. If maintained properly, they could even provide additional space for items you don’t use regularly.

However, since most people have limited interactions with their crawl spaces, there is a danger of water accumulating in them. Water in your crawl space will not just facilitate structural damages to your foundation and other parts of your home but also pose serious health and safety concerns and reduce the comfort level of your home. You should, therefore, take the necessary measures to keep the space as dry as possible.

What Causes Water In A Crawl Space?

The first step towards keeping your crawl space dry is identifying the various ways water gets there in the first place. This makes prevention possible and also allows you to solve the problem from the root to ensure it does not recur in the future. Below are the most common causes of water in a crawl space.

Poorly Graded Landscape

The grade of the land surrounding your home will determine how much water it will be exposed to. During heavy rains, runoff water will flow towards the lowest point of the area, even if this happens to be the foundation of your home. Trapped against the wall, hydrostatic pressure will force it through any cracks and into your crawl space.

For areas with heavy rainfalls, water will sometimes accumulate to the extent of turning your crawl space vents into spouts that will let vast amounts of water in. You should, therefore, ensure that the land surrounding your house slopes away.

Plumbing Leaks

Plumbing leak in basement

Each day, there are enormous amounts of water flowing in and out of your home. In most cases, the water lines bringing in the water and the sewer lines taking the wastes out pass through the crawl spaces. If a leak occurs here, vast amounts of water will enter your crawl space before you even suspect there is a problem.

The same applies to leakages that occur inside the house. When the pipes, sinks, and toilets malfunction, the water will flow downwards until it reaches your crawl space. Along the way, it will cause various structural damage, not to mention the massive waste of water. You should also watch out for garden sprinklers that spray water too close to your wall as the runoff from these can contribute to this problem.

Malfunctioning Gutters and Downspouts

Broken gutter

Even with proper landscape grading, malfunctioning gutters and downspouts will still get water into your crawl space. When the gutters block or leak, collected rainwater will flow down the walls and into your foundation.

Given that even a small roof is capable of harnessing vast amounts of water (each square foot collects 6 gallons per 1 inch of rainfall), a leaky gutter will send tremendous amounts of water near your foundation wall. The water will weaken your wall, and some of it will find its way into your crawl space.

For downspouts, they should drain the water a safe distance from your house. A downspout that sends all the water near your wall will do more harm to that area of your foundation than if there were no gutters in the first place.

Moisture From the Ground

Rainfall, breakage in underground water lines, lack of proper drainage, and a naturally high water table are some factors that contribute to excess water in the soil. If your home is built on excessively wet soils and has a dirt-floor crawl space, moisture from the underlying soils will find its way in.

The warmth from your home will cause the water in the soil to evaporate and collect on the walls, floors, and other surfaces in your crawl space. While this dampness may not seem like much, it will seep into your floors and walls, altering the internal temperatures and jerking up your power bills. It will also facilitate the growth of mold and mildew. These will not only reduce your home’s indoor air quality but also pose serious health risks to you and your family members.

Cracks In The Foundation Wall

Crack in foundation wall

Cracks in the foundation walls are also another way water finds its way into crawl spaces. These cracks are caused by various factors, including the effects of hydrostatic pressure and foundation settling.

When water pushes against your foundation wall, it will penetrate the tiniest cracks and expand them into wide pathways for more water to enter into your crawl space. If not sealed, these cracks will only get worse and could eventually result in the crumbling of your foundation wall.

How To Clean Up A Flooded Crawl Space?

If you find yourself with a flooded crawl space, this is not a problem that you should wait to go away by itself. Since it is under your home, you cannot depend on the sun and other natural elements to dry it out for you. In fact, the only escape for the water will be to seep into your walls and floors, where it will wreak significant structural damages and reduce the safety and comfort of your home.

Depending on the extent of you moisture problem, here is how to go about cleaning up your flooded crawlspace:

Use A Pump

For severely flooded crawl spaces with a lot of standing water, you should use a pump to get rid of the water. Position the pump’s suction hose in the crawl space and direct the drainage pipe a safe distance from the house to prevent the water from flowing back.

Use A Wet-Dry Vacuum Cleaner

water leak on the floor

Where there are only a few puddles of water, you could use a wet vac to suck up the water and dump it outside. However, if the water has accumulated to a depth of more than an inch, the job will be better handled using manual removal methods or a pump.

Manual Water Removal

If you do not have access to a pump or vacuum cleaner, there are manual ways you can clear out the water from your crawl space. You could use buckets to evacuate the water and dump it elsewhere. You could also use a broom to sweep out the water if it is only a few inches deep. These manual methods are, however, only applicable where there is enough access room into your crawl space.

Are you unable to pinpoint the exact source of the water in your crawl space? Worry not. Schedule a free inspection with one of our specialists who will help you identify and find the best solution to your problem.

How To Dry Out Your Crawl Space

Removing flood water and puddles is not enough to keep your crawl space safe from the effects of water. The next step is to dry out even the tiniest droplets and vapor from the area. Below are the steps you should follow to keep your crawl space completely moisture-free:

Step 1: Clean and clear the crawl space

After dumping out all the standing water, you should remove any wet materials previously stored in the crawl space. These will have likely absorbed moisture from the damp environment and will inhibit the drying process. Sharp tools will also make it difficult to waterproof and encapsulate your crawl space.

If your crawl space was damp for long, mold and mildew will likely have formed. These should be removed and cleaned out, together with any animal droppings, insect shelters, termite tunnels, wastes, and other construction debris in the area.

Step 2: Dry out the soil using a sump pump

sump pump

To ensure moisture from the floor does not enter your crawl space through evaporation, you should dry out the floor using a sump pump. To install a sump pump, a sump hole is dug in the lowest point of your crawl space to collect water from the surrounding soils. When the water reaches a certain level, it is pumped to a safe distance from your home’s foundation.

Sump pumps are especially useful in areas with high water tables or those prone to flooding, where the moisture content of the soil is always high. They could be automatic, triggered by sensors when a certain level is reached, or manual where you will be required to check on the level and pump out the water yourself.

Step 3: Install a dehumidifier

Dehumidifier in a basement

If there is outside air flowing into your crawl space, then moisture from the air will likely settle on surfaces in your crawl space. To keep it completely dry, you should install a crawl space dehumidifier. A dehumidifier draws in the moist, warm air from the surrounding, condenses and collects the moisture, and pumps out the cold, dry air back into your crawl space.

It is most suitable for crawl spaces prone to condensation problems and water droplets settling on surfaces. For areas with floods or puddles of standing water, pumps and manual evacuation will be more effective.

Step 4: Install ventilation fans

a crawl space with air mover to dry out the structure

Without proper airflow in your crawl space, it will be difficult for the dehumidifier to draw moisture that has settled on surfaces. Ventilation fans increase the speed of the air, enabling it to carry more water vapor which will then be drawn in and trapped by the dehumidifier.

It is, therefore, recommended that a dehumidifier works together with ventilation fans for maximum efficiency.

How To Prevent Future Flooding

Prevention is ultimately easier and cheaper than treating the problem. Below are some measures you can take to prevent water from finding its way into your crawl space:

Grade Your Landscape Properly

You should ensure there is a slope extending at least 6–8 inches away from your house to drain all excess water. For the soil making the first few feet of the slope, avoid using topsoil as it is highly porous and will absorb most of the water and dump it near your foundation. Instead, you should use clean fill dirt that is more compact and will provide more resistance to water and allow it to flow away from your home.

You should also avoid planting flower beds too close to your home as the plants will retain water and prevent it from draining away, keeping the area moist. If you fail to water the plants sufficiently, their roots will extend towards the dampest areas around, which, in this case, will be towards your foundation wall. Here, their tendons will penetrate cracks in the walls and expand them, creating more structural and moisture problems.

Proper grading may not be enough for areas with a naturally high water table or those prone to flooding. Consider using French drains to keep the soils around your home from soaking in excess water (but check out our article here to determine whether or not you are a good candidate for French drains in the first place…).

French drains are made by digging trenches deeper than the surrounding water level, then lining them with perforated pipes and covering them with gravel. Water from the surrounding soils will drain into the pipes, where it will be directed away from the house either by gravity or using sump pumps.

Keep Plumbing And Drainage Fixtures In Good Condition

As discussed earlier, water from malfunctioning gutters, downspouts, and plumbing leakages will contribute greatly to a wet crawl space. You should, therefore, check the gutters and downspouts to ensure they are safely draining all your roof water to the required area.

For plumbing leakages, monitoring your usage regularly using a meter will make it easier to notice when there is an issue. Fixing all leakages in time will not only save you from excessive water bills but also help maintain the structural integrity of your home.

Install Flood Vents

Where it is inevitable to prevent water from getting into your crawl space, you should consider installing flood vents. In some areas, the building codes require that all crawl spaces have flood vents to prevent water damage from excessive flooding.

These vents should be installed on the lower wall of the crawl space to allow excess water to flow out and away from the crawl space.

How To Prevent Moisture In Your Crawl Space

After ensuring that water will not torrent into your crawl space from outside, you should now take the necessary measures to prevent moisture from seeping in. This can be achieved by crawl space encapsulation and waterproofing.

Crawl Space Encapsulation

Crawl space encapsulation involves completely sealing the crawl space to prevent even the tiniest drops of water from finding their way in. It involves:

Sealing Cracks On The Foundation Wall

The first step towards total encapsulation is sealing the cracks on the foundation wall to prevent water from seeping through. This can be done by applying layers of sealant to the cracks. For large gaps on the foundation wall, cement grout can be used to repair the cracks.

However, before repairing any cracks, investigate their origin to prevent them from recurring. For instance, if foundation settling was responsible for the cracks, lifting the foundation will not just seal the gaps but will also ensure no further settling occurs.

Installing A Water Barrier

One way to keep your crawl space completely moisture-free is by installing a vapor barrier. This involves taping sheets of thick polyethylene plastic onto the floor and walls of your crawl space to prevent water from seeping in through the walls and settling on the floors.

A water barrier can also be installed on the exterior wall foundation wall, especially if the soil around has high water content. The moisture barrier will prevent hydrostatic pressure from pushing directly on the wall, limiting the chances of water penetration.

Crawl Space Insulation

Insulating the water pipes passing through your crawl space will prevent water from condensing and settling on their surfaces, especially in areas with high humidity levels. Pieces of rigid foam insulation should be wrapped around the pipes, floor joists, rims, support beams, and other exposed fixtures to protect them from dampness.

Install A Dehumidifier

Even after completely encapsulating your crawl space, there will still be water vapor that will find its way in. Install a dehumidifier to keep the humidity levels in check, where excess moisture will be trapped and periodically emptied outside the area.

Let The Experts Help!

Keeping your crawl space moisture-free is not an option if you want to maintain the safety and health of your home. It can, however, be a very challenging task without the necessary tools and know-how. This is why you should seek the help of professionals to ensure the process is done effectively for long-lasting benefits.

At Regional Foundation Repair, our contractors are highly skilled and experienced in helping homeowners solve their foundation and crawl space water problems. Contact us and tell us more about your issues, and you will be on your way to enjoying the peace of mind associated with a safe, comfortable and healthy home.

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Sam Smith Foundation Repair Consultant
SHORT BIO: Hey, I'm Sam Smith. I'm one of our service techs here at Regional Foundation Repair. I'm here to help you learn more about your home's foundation. I've been doing this for a while, so I have a few insider tips and tricks to share!

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