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Why Is My Crawl Space Flooded When It Rains? (Causes & Solutions)

Why Is My Crawl Space Flooded When It Rains? (Causes & Solutions)
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As a homeowner, you want your place to stay as clean and dry as possible. That’s why it can be frustrating to find your crawl space flooded when it rains.

Stagnant water in your crawl space can sit there for months or maybe even years. Such a condition can pose hazards to your health and your home.

In this guide to crawl space flooding (due to rain), we’ll discuss possible causes, negative effects, prevention tips, and recommended solutions. Let’s get started!

What Is a Crawl Space?

A crawl space is a narrow area typically found between the first floor of a building and the ground. This is where your home’s plumbing and wiring can be found.

You might not see your crawl space often. This could make it tricky to monitor what’s going on down there.

Signs of Crawl Space Flooding

There are several warning signs that can point to flooding in your crawl space. Be on the lookout for any of the following:

  • Mold on walls and surfaces
  • Damage caused by termites
  • Rotting of wood floors
  • Floors becoming uneven or “floor cupping”
  • Unusual humidity indoors

Once you see the signs, don’t delay an inspection of your crawl space. Be ready to act the moment you see them.

Causes of Crawl Space Flooding

Have you spotted signs of flooding in your crawl space when it rains? Or maybe you’ve gone down there yourself and caught sight of some extensive flooding.

If you have, it’s time to find and address the root cause of the issue. The following culprits might be found in your home:

  • Faulty drainage system
  • Damaged foundation
  • Defective sump pump
  • Overwhelmed sewage system

Promptly identify and address the cause of your crawl space flooding. This will prevent more water from coming in.

Effects of Crawl Space Flooding

You might consider leaving your crawl space flooded to save time and effort. However, leaving your flooded crawl space unattended can have the following worrying effects:

1 – Structural Damage

Too much moisture in wooden floors can cause “floor cupping.” This happens when the underside of the floorboards gains a lot of moisture, causing them to swell.

This causes the wooden planks to be flat in the center and raised on the edges. Gaps then begin to form between the planks.

When you leave your crawl space flooded for too long can permanently affect your home’s foundation.

2 – Mold

A moist crawl space is an ideal environment for mold. Mold loves to grow on organic surfaces like wood.

A severe mold problem can cause airborne spores to contaminate the upstairs area of your home. This can impact your health and your family negatively.

3 – Pests

Pests such as rats, spiders, termites, and even snakes would thrive in a wet and humid crawl space. Getting rid of these critters can mean additional costs, too.

4 – Dust Mites

A large amount of air in your house might originate from the crawl space below. If your crawl space is flooded, it might cause humid air and musty odor to circulate through your house.

This type of air quality is especially attractive to dust mites.

5 – Health Concerns

Mold, pests, dust mites, and poor air quality can trigger your family members’ allergies or asthma.

Stagnant water can also develop a foul odor which can be uncomfortable to put up with.

6 – Increased Heating or Cooling Costs

An area with damp or humid air requires more energy to heat or cool. This translates to higher energy bills for you and your family.

7 – Lower Property Value

The sight of mold and flooding in your crawl space is unappealing to potential buyers. Studies have shown that flood events tend to decrease the value of housing by 18–25%.

Solutions for a Flooded Crawl Space

It can be daunting to face a crawl space that’s heavily flooded from the rain. But the sooner you address a flooded crawl space, the better.

Here are some ways to tackle the problem:

1 – Use a Pump

A pump that’s used for general purposes will do. It’s the most practical, efficient, and cost-effective solution if your crawl space is heavily flooded.

Just put the suction hose in the water and position the drainage hose properly. Make sure that the water flows to an area where it can’t return back into the crawl space.

Switch the pump on and let it do its job. Adjust the hoses as needed.

2 – Get a Broom

If the type of flooding you have is wide but not over an inch deep, a broom will do the trick. Sweep the floodwater out.

Don’t forget to get rid of wet debris in the area so that it doesn’t interfere with your sweeping.

3 – Use a Wet Vacuum

A wet vac is best used when only a few puddles are left in your crawl space. Then, after vacuuming, you can easily dump the water outdoors.

Cleaning your flooded crawl space doesn’t end with getting rid of all the water. You have to dry the space thoroughly, too!

For starters, check to see if no more water can be found anywhere. Next, do some mold control by cleaning up the surfaces and disposing of moldy items.

It’s also good to do a safety check of all wirings and outlets in the space.

Lastly, run the dehumidifier for a few hours. You can also use electric fans to blow air into your damp crawl space.

Tips on How To Prevent Crawl Space Flooding

After drying out your flooded crawl space, the ultimate goal would be to keep it that way. Prevention is always better than cure, right?

A dry crawl space is better for your health and for your wallet as well. Follow these tips to prevent your crawl space from flooding when it rains.

1 – Get a Sump Pump

If you live in a flood-prone location, getting a sump pump is a good move. Be sure to install one that has a reliable sump liner, a trusty pump, and a sealed lid.

There are special sump pumps out there that are designed for crawl spaces. For maximum efficiency, you can opt to dig a drainage pathway on the crawl space edges.

This should lead the water towards the sump pump.

2 – Seal the Crawl Space

This one is for homeowners who want to keep their crawl space 100% dry. It involves using airtight doors, vent covers, and a vapor barrier in your crawl space.

It’s best to consult a professional to get this done properly.

3 – Build Flood Vents

A flood vent is an opening in the wall that separates your crawl space from the outside of your house. It’s built to let water pass through instead of being trapped.

This tip is most applicable to homes located on flood plains.

4 – Repair and Maintain Your Drainage Systems

Take a look at your drainage system, including downspouts, gutters, and the land grading of your home. Then, make the necessary repairs and changes needed to ensure proper drainage of rainwater.

5 – Repair Cracks in Foundation

The smallest of cracks in your home’s foundation can be an entry point for rainwater. Inspect the foundation frequently and have cracks repaired as soon as possible.

6 – Sewage System Maintenance

Inspect and unclog your sewage system on a regular basis. This will help prevent your sewage system from getting overwhelmed by heavy rains.

Sewage backups can also occur and cause water damage to your crawl space. A sewage backup can be prevented in many ways, such as trimming tree roots and using a backwater prevention valve.

Final Thoughts

It’s common to find your crawl space flooded when it rains. As such, it might be tempting to just let the problem be.

Unfortunately, a flooded crawl space leads to numerous negative effects on your property, your health, and your budget. Taking note of the signs of flooding can help you take action earlier.

Understanding the causes can also help you address the issue properly. A pump, broom, and wet vac are some of the tools you can use to restore your crawl space to its original condition.

You can also make use of tips such as maintaining your drainage systems, repairing your foundation, and inspecting your sewage system. Following these tips can prevent a host of future problems from flooding through your day.

Stay safe — and dry!

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