Your Guide To Waterproofing Your Crawl Space

If your home has a crawl space for a foundation, this area can become a huge headache. Not only can it attract pests, but it can also accumulate moisture, leading to water damage. Over time, this damage can weaken the supports and potentially ruin your home’s foundation. To avoid catastrophe, you should waterproof your crawl space.

Fortunately, there are several ways to do that, and Carolina Pest Management can help you with each option. Let’s break them down, step by step.

How Can I Waterproof My Crawl Space?

technician in crawl space performing moisture control and crawl space care

Technically, there are three unique ways that you can waterproof your crawl space. Realistically, though, you might have to combine two or more methods to ensure that your foundation stays dry all year round. The extent of your waterproofing depends on the specifics of your situation.

For example, if you live in a wet and humid environment (like North Carolina), you’ll likely have to use all three strategies. Conversely, if your home is in a dry, desert climate, one solution might be more than enough. Here’s a quick overview of these options.

Vapor Barriers & Encapsulation

Usually, the simplest method is often the best. Rather than figuring out a way to remove water from your crawl space, vapor barriers prevent it from forming at all.

A vapor barrier is just a large plastic sheet that covers the entire foundation. It’s attached to the support beams so that no water can seep in through cracks or holes. On average, vapor barriers are around three to six millimeters thick and last between five to 10 years.

For a more comprehensive solution, you can choose encapsulation. This process takes longer and costs more, but it offers better protection and lasts at least twice as long. With encapsulation, you cover all surfaces of your crawl space with about 20 millimeters of material. Encapsulation can last up to 25 years and prevents water much better than a vapor barrier.

Dehumidifiers & Heat Vents

One issue with most crawl spaces is that they use wooden support beams. Wood can absorb water and release it back into the air, creating a moist environment. So, a dehumidifier can capture any moisture in the air and send it outside.

Automatic heat vents can also help relieve humidity issues. When the weather gets hot, the vents open so that air can escape the crawl space. Then, when the temperature drops, the vents close. This process helps reduce the amount of humidity, although it’s not very precise. Ideally, you’ll install both vents and dehumidifiers to keep your crawl space dry.

Sump Pumps

Water damage doesn’t just occur because of moisture in the air. Flooding can also be a huge problem, whether it’s from a storm or a burst pipe. If water gets into your crawl space, it’s hard to remove. A sump pump is a semi-permanent installation that pumps water away from the crawl space or basement.

These pumps only work if there is a slope on the ground. If there isn’t, you might have to grade your foundation so that water will naturally accumulate in the pump. Otherwise, the machine won’t be able to remove it all.

Steps To Waterproof a Crawl Space

Let’s break down the basic steps to installing each of these solutions in your crawl space. In each case, you need to go into your crawl space and remove any debris, pests, or other items. Doing this will make it much easier to install these waterproofing solutions.

Vapor Barriers & Encapsulation

  • Step One – Measure Your Crawl Space: You need to ensure that you have enough material to cover the entire ground. Also, give yourself some extra so that you can create airtight seals around the support beams and along the walls. If you’re encapsulating your crawl space, you need to measure all surfaces.
  • Step Two – Get the Material: Buy as much plastic sheeting as necessary. Again, give yourself a small buffer, just in case.
  • Step Three – Cut Flaps for Supports: The barrier will have to wrap around the beams, so make sure that you have flaps so that the plastic can go up the beam a few inches.
  • Step Four – Secure the Barrier: Use waterproof adhesive to secure the plastic to the walls and supports. Also, use plastic stakes to secure the barrier to the ground.

Dehumidifiers & Heat Vents

  • Step One – Measure Humidity Level of Your Crawl Space: You can buy a thermal hygrometer for pretty cheap (less than $20). Use it to measure the humidity levels of your crawl space. Ideally, the area should hover between 30 and 60 percent, although 50 percent or less is ideal. Be sure to check the humidity when it’s at its highest point, such as late in the day. Doing this ensures that you have a good idea of the maximum level.
  • Step Two – Buy a Dehumidifier: Depending on the size of your crawl space, you may need multiple machines. Verify their capacity and that they can run automatically. Otherwise, you’ll have to manually switch them on whenever it gets too humid.
  • Step Three – Install Heat Vents: You should use a contractor for this step since there may be cutting or light construction work involved. In some cases, all you have to do is replace your current windows with heat vents. In other instances, you might have to make holes for new vents.
  • Step Four – Test Your Dehumidifiers: Check on them regularly during the first few days to ensure they’re working correctly. Also, test different spots in your crawl space to see if there are any dead zones. If necessary, readjust your installation points accordingly. After a few days, check on the machines bi-weekly to empty their canisters and replace any filters.

Sump Pumps

  • Step One – Measure Your Foundation Grade: The easiest way to do this is with a level. Find the lowest point of your foundation – that’s where the pump will go. If your slab is flat, you’ll need to get a contractor out to create a slope. Otherwise, water won’t drain into the pump.
  • Step Two – Dig a Drainage Ditch: This part is necessary so that the water has somewhere to go. The ditch should extend at least 20 feet from the foundation if possible.
  • Step Three – Lay Pipe: Once the ditch is ready, put the water pipe inside. PVC is ideal because it’s durable and won’t rust. Then, cover the pipe with loose gravel and soil.
  • Step Four – Install the Sump Pump: You can buy hardwired or battery-operated sump pumps. We prefer the latter because they don’t have to be plugged in. Also, make sure that the pump is self-priming. Otherwise, it won’t turn on when it’s needed. Connect the pump to the pipe.

Can I Waterproof My Own Crawl Space, or Should I Hire a Contractor?

If you’re just installing a vapor barrier, you can do the project yourself. However, for sump pumps and heat vents, it’s much better to trust professionals. This way, you can get guaranteed results and feel confident that everything will work properly.

If you want to encapsulate your crawl space, a contractor is also necessary because the job is much more intense and requires more precision.

How Long Does It Take To Waterproof a Crawl Space?

The answer depends on a few factors, such as:

  • Size: A larger crawl space will take longer to waterproof.
  • Method: Sump pumps are the most time-consuming option unless you just have to replace an existing pump.
  • DIY vs. Contractor: Contractors may take longer because they’re more thorough.

Overall, a vapor barrier can take a few hours (not including planning). A sump pump might take a few days to install if you need to dig a drainage ditch first.

How To Prepare for Crawl Space Waterproofing

The best way to prepare your crawl space is to clean it out. There are likely pests, cobwebs, and other debris collected down there, so you want to remove all of it beforehand. Another way to get ready is to measure the size of your crawl space and the distance between posts. This way, the contractor doesn’t have to take time to measure it themselves.

Contact Carolina Pest for Crawl Space Waterproofing

Waterproofing your crawl space can be a big job, which is why you should trust us. We can help you install everything from heat vents to sump pumps. Better yet, we can remove any pest infestations that may be lurking in your crawl space already. 

Ready to waterproof your Charlotte home’s crawl space? Contact the professionals at Carolina Pest Management by calling 704-350-2674 today!

By Kristin Dodd

Kristin Dodd, the President of Carolina Pest Management, has been with the company full-time for over 20 years, but has been a part of the family-owned business for much longer. She is currently an active board member of the North Carolina Pest Management Association, and was the President from 2010-2011. She is a licensed operator in...