how much does it cost to seal a basement

Last Updated: Wednesday, January 12, 2022

How Much Does it Cost to Have Your Basement Walls Sealed and Waterproof?

Note: This page is about sealing basement walls from the inside with waterproof coatings.

Sections: Overview | Product Costs | Installation Cost | DIY or Pro

Overview

Owning a home with a basement has many great benefits, but to take advantage of the extra space under your house you will need to make sure the basement is sealed from the elements. Waterproofing your basement is crucial in avoiding a huge mess after a bad rain storm and will give you peace of mind knowing that water will not leak in over time.

The good news is that if you can handle this basement sealing project before you have a problem, you can avoid more complicated and costly exterior repairs that may be necessary. In this Costimate we will focus on the cost of sealing your interior basement walls before you have issues with water. We’ll explain the different basement waterproofing techniques, as well as provide you with the cost of the different sealant products available on the market. At the bottom of the page, you’ll find a section that lets you compare basement water sealing costs from other leading websites, as well as review what homeowners around the country have paid for their project. Once you have a better understanding of how much it will cost to seal your basement, you’ll be able to decide if this is a do-it-yourself project or if you need to hire a professional to do the work.

Product and Supplies Cost Details

Waterproofing and Sealer Price Factors

Many factors will affect the right basement sealant for your specific needs. Before running down to Home Depot or Lowes for supplies, it’s important to make sure that you understand which basement sealing product and solution is right for you. Sealing concrete basement walls that are not yet leaking or causing problems is going to be the most affordable solution and can usually be done by one person in a weekend. If your basement is leaking or you have an already finished basement, the cost of sealing your basement may dramatically increase if you want to get the job done right. Step one in determining your basement waterproofing cost will depend on which of the following options fits your situation:

• Unfinished Concrete Basement Walls with No Leaks – Cheapest and easiest solution, also a good DIY project with little prep work for the handy homeowner.
• Unfinished Cinder Block Walls with Little Moisture and No Leaks – Another project that you can handle yourself if you are handy.
• Finished Basement Showing Signs of Moisture – This project could get very expensive, as it can require tearing out walls and carpet to diagnose your problem.
• Basement with Visible Leaks, Wetness and Standing Water – This project requires professional help. We recommend getting in touch with a local expert to handle this project.

Regardless of the current situation, you can expect to spend the following retail prices on your basement sealant, depending on which type of walls you have:

• $30 – $40 / 100 square feet | Concrete Basement Wall Sealant
• $40 – $50 / 100 square feet | Cinder Block Basement Wall Sealant

Cost of Supplies

Once you’ve determined how you will seal your interior basement walls, you will want to factor in the following supplies to your overall basement sealing cost:

• $15 – $20 | Course bristle brush to clean walls before applying sealant.
• $6 – $10 | Heavy duty paint brush(s) for applying sealant to concrete walls.
• $8 – $12 | Masonry caulk to seal corners, seams and any visible cracks.
• $80 – $100 | Epoxy based floor paint – Sealing the floors goes hand in hand with sealing the walls and can prevent water from seeping up over time.
• $4 – $6 | Latex gloves to protect skin from chemicals (Box of 50).
• $15 – $30 | Per gallon of paint – Many of the sealants dry clear or come only in white/gray. Now is the right time to paint the walls.
• $30 – $50 | Miscellaneous supplies like plastic, tape, rags, etc.

Permits, Inspection, and Installation Costs

As we mentioned above, the most important part of this project is inspecting your basement for water and moisture. Many local companies will provide a free inspection of your basement for mold and moisture in the walls. If your basement shows no signs of moisture then an inspection should not be necessary. Permits are not required for a simple sealing of interior basement walls and floors.

Installation Labor Costs

The cost of labor will depend on the time it takes a local handyman to complete the job.

• $50 – $100 per-hour | Average cost of handyman in the US

As with any project, there are a number of factors that will determine how much a handyman will charge you and how long it will take. Some projects may be quoted on a “per-project” basis, rather than hourly, depending upon who you work with.

A few things that will affect your overall costs:

• Size of basement – This will determine the cost of supplies and time to complete the job.
• Access to Bare Walls – Existing walls, carpet, paneling, or anything built against your walls will require removal before sealing.
• Condition of basement walls – Aged or cracked walls may require more prep work and coats of sealant to properly prevent moisture.
• Amount of Clutter – You can expect the cost to go up if your handyman is going to have to spend moving things around to get the job done.

Completed Installation Time

The time it takes to waterproof your interior basement walls with sealant will vary depending on the size of the basement and number of walls. The following guide can give you a rough estimate of how long you need to set aside.

• 8 – 10 hours | 1,000/sq ft basement with concrete walls
• 10 – 12 hours | 1,000/sq ft basement with cinder block walls
• 16 – 24 hours | 1,000/sq ft basement with cracks/holes that need to be fixed before sealant is applied

The total labor hours described above include brushing on the first coat of sealant and then using a roller to apply the second coat. The times do not include the typical 4-hour time frame for drying in between coats. Cinder block walls absorb the sealant more than concrete walls and can take longer to properly seal.

DIY or Hire a Pro

Sealing the walls in your basement is definitely a worthy DIY project for those who want to tackle it. As long as you spend time thoroughly cleaning and preparing the walls, application of the sealer is not much different than painting a large room. Of course, if your basement is already finished, you might consider talking to a pro first. The added prep and rebuild work, might be more than you planned for. Another thing to consider is the reason your basement is wet in the first place. Are your gutters not working properly? Do you have an outside drainage issue? You’ll want to solve the cause for water, as much as the water itself.

• Requires a good bit of activity to clean and prepare walls before applying sealer.
• If you already have walls built against your foundation, there can be a lot of prep work removing them.
• If you’re sensitive to chemical smells, it may bother you.
• Depending on the height of your basement, you may need to work from a ladder to reach higher points, that are below outside grade.

We recently took all the 70’s paneling off the basement walls and exposed the cinder block foundation. There was quite a bit of work to get the furring strips off the block walls, and prep work took 2 full days to remove the nailers, patch the wall with cement, and prepare for the waterproofing sealer. From there it was a cake walk and the basement was completed in 3-4 days total.