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Glossary

Basement Waterproofing

Basement Waterproofing

This is a system of coatings, drains, and pumps used to keep water out of your lower level. You might need it if your basement smells musty or gets wet after heavy rain. It protects your foundation from water damage and stops mold growth.

Reviewed by Sarah JUpdated July 2, 20263 min read

Origin

The term combines basement, from the French word soubassement meaning lower part of a building, with waterproofing. Modern waterproofing methods became common in the 1900s as homes added livable spaces below ground.

How you'll see it used

  • The contractor handed us a quote for 6,500 dollars to install an interior French drain and a new sump pump to fix our wet basement.
  • Our home inspection report noted white chalky powder on the foundation walls, suggesting we need a basement waterproofing expert to look at the moisture problem.
  • I told my neighbor I was tired of cleaning up puddles in my lower level, and he recommended a local basement waterproofing company to seal the cracks.

What It Is

Basement waterproofing is a set of tools and methods used to keep water out of your home. When it rains, water pools in the soil around your house. This water pushes against your concrete walls. Eventually, it finds a way inside through tiny cracks. Waterproofing stops this from happening.

There are two main ways to waterproof a basement. Interior waterproofing manages water that gets inside. Contractors dig a trench around the inside edge of your basement floor. They install pipes called a French drain and connect them to a sump pump. The pump pushes the water outside. Exterior waterproofing stops water before it touches your walls. Workers dig down to the bottom of your Foundation & Structure on the outside. They apply a thick waterproof coating to the walls and install drainage pipes in the yard.

Why It Matters To You

A wet basement causes massive problems for your house. Water damages drywall, ruins wood floors, and destroys anything you store in boxes. Even a small amount of moisture creates a perfect home for mold. Mold spreads fast and makes the air in your entire house unhealthy to breathe.

Water also damages the structure of your home. When water freezes and thaws inside concrete cracks, it makes those cracks bigger. Over time, your walls can bow inward or crumble. Fixing structural damage costs far more than waterproofing. If you notice strange Smells & Odors coming from your lower level, moisture is usually the culprit.

What To Watch For

You don't need to wait for a flood to know you have a water problem. Your basement gives you plenty of warning signs. Look for these clues:

  • White, chalky powder on your concrete walls.
  • Paint that bubbles or peels off the walls.
  • Rust spots on your furnace, water heater, or metal pipes.
  • A damp, musty smell that never goes away.
  • Dark stains on the walls near the floor.
Don't ignore small puddles near your basement walls. Water pressure outside your home will only get worse over time, and a tiny leak can turn into a flooded room during the next big storm.

What It Costs

Waterproofing costs depend heavily on the method you choose. Minor fixes like painting on a waterproof sealant cost 500 to 1,500 dollars. A full interior drain system with a sump pump usually costs 3,000 to 10,000 dollars. Exterior waterproofing is the most expensive option because it requires heavy equipment to dig around your house. This method often costs 10,000 to 20,000 dollars. Keep in mind that these ranges vary based on where you live and the size of your home.

Before you spend thousands of dollars, check your gutters and yard. Sometimes, cleaning your gutters and extending the downspouts away from the house fixes the problem. You can also adjust your Landscaping, Drainage & Outdoor grading so the dirt slopes away from your walls. These simple steps keep water away from your house in the first place.

How To Maintain It

Once you pay for a waterproofing system, you need to keep it in good shape. Sump pumps do a lot of hard work. You should test your pump at least twice a year. Pour a bucket of water into the pump pit and make sure it turns on. You also need a battery backup for the pump. Severe storms often knock out the power right when you need the pump the most.

If you have an exterior drain system, keep your yard clear of deep tree roots. Tree roots can grow into the buried pipes and clog them. You should also walk around the outside of your house after a heavy rain. Look for spots where water pools near the foundation. Fill those low spots with dirt to keep the water moving away from your home. Checking these things twice a year saves you from sudden basement floods.

Frequently asked

Can I waterproof my basement myself?

You can apply waterproof paint or seal small cracks yourself to stop minor leaks. However, you should hire a professional for major water problems. Digging trenches and installing drain pipes requires special tools and knowledge to do safely.

Does basement waterproofing increase my home value?

Yes, a dry basement makes your home much easier to sell. Buyers worry about mold and foundation damage when they see a wet lower level. A good waterproofing system gives buyers peace of mind and adds usable living space.

How long does a waterproofing system last?

Exterior waterproof coatings usually last 10 to 15 years before they start to break down. Interior drain pipes can last decades as long as they don't fill with mud. You will likely need to replace the sump pump every 7 to 10 years.

Appears in these guides

DIY vs. Hiring a Pro

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