Best Basement Wall Sealer: Sealant for Basement Walls

If your basement is prone to moisture or you want to avoid it in general, waterproofing or sealing your basement wall is a great choice. A proper wall sealer will ensure your basement isn’t as prone to substances like moisture built-up or mold and mildew. 

But, a wall sealer is not just meant for your wall. It can also enhance the overall strength of your house as basements are easily exposed to various attacks that can leave the foundation weak. 

Another huge benefit of sealing the basement wall is cost. Avoiding the presence of molds and mildew can help cut down or prevent the cost of repairing and unnecessary renovations. 

An effective sealant can help bridge seams, joints, gaps, etc., around the house, which in turn prevents outdoor substances from leaking into the house. 

In today’s article, we’ll cover various wall sealers for your basement along with some tips and suggestions to improve your house. Let’s get started!

Best Sealant for Basement Walls

Here are 5 of the best selection of sealants for basement walls. Let’s have a look!

1 Liquid Rubber 1 Gallon Basement Sealant

This basement and foundation sealant from Liquid Rubber is a water-based sealant that can help cover any DIY home projects. Given its water-based nature, it is nature-friendly, solvent-free, and entirely safe for any indoor and outdoor use. 

Once cured, the sealant is highly flexible thanks to its 900% elongation that prevents damages post-application. Since the product is applied indoors, there isn’t much need to worry about high UV exposure as well. 

Application-wise, this is a ready to use & easy to apply sealer. Hence, there’s no need for any mixing. You can use and apply it like a paint job, except in a thicker form. The sealer can also be stored for later use. 

In addition, the sealant can be used on other surfaces such as shower lines, fence posts, decks, ICF’s, planter boxes, and more. So, if you have any leakage-prone areas, you can also apply the Liquid Rubber sealant. 

Overall, the LR basement sealant is one of the best options for sealing or waterproofing your house. It is a nature-friendly, versatile, and easy-to-use sealant that can serve various uses, especially if you’re interested in doing a DIY project. 


  • Easy to use
  • Solvent-free


  • Not ideal for UV exposure

2. KILZ Basement Paint

If a concrete and masonry sealant is what you’re looking for, the KILZ basement paint is the most compatible pick. The company utilizes nanotechnology to create its main barrier in preventing water infiltration on cracked surfaces. 

This sealant is also an excellent choice for those with a sensitive nose as the mixture comes with minimum odor. It’s a great solution for interior basement walls as well as exterior surfaces. This sealant is also alkali-resistant, making the surface all the more durable and sturdy post-application. 

The final finish of the sealant is completely mold & mildew resistant. Plus, you can easily paint over the surface with pastel or mid-tone colors. This all-in-one mixture does not require any professional workers for completion. Its easy-to-use application makes it a suitable product for beginners as well. 

We love the KILZ basement paint for its versatility over any other thing. It can be applied on basement walls, concrete blocks, masonry walls, metal surfaces, etc. This means you can do a complete renovation with a couple of KILZ sealant cans, which can help reduce costs in the long run. 


  • Value for money 
  • Dries quickly 


  • Requires primer prior to application 

3. AMES BWRF5 Liquid Rubber

The liquid rubber solution from AMES is designed with the purpose of waterproofing cinder blocks, concrete walls, and more. It’s a ready-to-use solution that can be applied on various surfaces to prevent excess moisture, mold, and mildew. 

The AMES sealer serves as a great adhesive for covering cracks thanks to its well-formulated and high-strength sealer. The sealant works on concrete, wood, metal, etc. Additionally, it has very little odor and can be applied in numerous ways such as spraying, brushing, rolling, etc. 

It also comes with over 1000+ elongation percentage, which helps in enhancing its flexibility without minimizing durability. This one is also an environment-friendly alternative that beginners can use with ease. 

The sealant formulation also comes with mold, fungus, and mildew resistance and can be easily cleaned up with water. This means you don’t have to worry about having a messy application. 


  • Strong adhesion and odorless
  • Fungus, mold, and mildew resistant 


  • Takes time to dry

4. Liquid Rubber 5-Gallon Concrete Foundation sealant

Designed as a solvent-free, environmental-friendly sealant, the LR basement sealant does not come with any handrail odor. This allows users to handle the solution freely without the need for any breathing masks and covers. 

It can also serve as a protective finish for various surfaces such as foundation, decks, planter boxes, etc. Just think of the Liquid Rubber sealant as a gold mine for any DIY enthusiast. Not only will it save money, but it can be a great waterproofing solution for anything and everything around the house. 

Whether it’s bridge joints, gaps, vents, seams, etc., you can apply the sealant without any other mixture via a paint roller or a brush. The application is not as complicated. Hence, even beginners will find it easy to use the sealant. 

This sealant is also applicable on both indoor & outdoor surfaces and is completely reusable. You can simply seal off the container and store it for future use. 


  • Environmental friendly  
  • Reusable 


  • Limited instructions for application 

5. Flex Seal Canned Liquid Rubber

This liquid rubber solution in a can is the creation of Flex Seal that allows users to apply it in any way they desire. You can dip, pour, brush, or roll, and the result will be the same. A waterproof and mildew-free surface. 

Furthermore, the sealant is UV resistant, meaning you can use it for outdoor applications as well without any worry of sun damage. The product is also highly resistant to rust and corrosion. Similar to many canned sealants, the flex seal liquid is also easy to use and apply. It easily seeps into holes or cracks, which prevents the top enemy of your basement – moisture. 

Apart from basement use, the sealant works just as effectively on roofs, pools, sidewalks, flooring, and more. It is extremely flexible and does not sag or drip as the sealant forms a breathable and durable surface once cured. 

Overall, it’s a great option for a sealant. Just remember to have the right amount of patience for it to dry properly. A quick-drying process is not the strongest suit of flex seal. However, the product makes up for it through its versatile application. 


  • Flexible and crack free
  • Expensive 


  • It takes time to cure

How to seal cracks in basement walls step-by-step:

Before you begin, you must ensure the crack is fully dry because if the gap is even a bit damp, the procedure will not work. Dry the crack with a blow-dryer and wait for 15 mins, then continue with the repair.

Cracks of all sizes occur during earthquakes, or anytime a house settles or shifts the ground. Although these cracks don’t necessarily cause much worry or pose a threat to the house structure, you might face problems regarding insects, radon gas, and groundwater.

Today, we’ll present to you a quick and effective method for patching up your cracks with a filler that’s appropriate for your basement wall. 

Inspect the crack or suspect area

Have a walk around the perimeters of your home and inspect every detail, including doors and windows, the crawl space, and pipes. Horizontal cracks and stair-step cracks are always a concern as they pose a significant threat to the foundation, but hairline cracks and vertical cracks are pretty common and not serious at all.

After you’ve acknowledged what type of crack it is and where it lies in the house, you can now start to approximate how many gallons of filler you’ll need to patch things up. 1 gallon per 20sq ft is required if there are exterior cracks, and for interior cracks, you will need 1 gallon for 50 sq ft.

Clean up the area

Before you fix anything, you must clean it and make sure it’s well dried. So, it would help if you thoroughly cleaned the crack and even scrubbed it clean by diving 1 or 2 inches beyond it. You can use brushes made from materials like nylon or a metal wire brush, and mix a solution with the brush and get cleaning.

If it’s wet, check where the humidity is coming from, and if it’s nothing, remove all the moisture from the crack. Try to remove the dust particles, and debris stuck within the crack too. If you can’t use the brush, you can clean it with the help of a vacuum cleaner.

The removal of the debris and scraping out everything within the crack will help make the application of the liquid easier.

Apply heavy coat, wait to dry

Arrange your pre-mixed or ‘setting-type’ compound into two batches, or you can purchase two containers of it. Separate the base into equal parts with nails to align the injection ports so as to avoid contamination.

With a wide putty knife, spread the sealer on the sides of the crack and cover the injection ports with the crack sealer with only their necks left extended and untouched. Let it dry for 6 or 10 hours before you seal the injection ports with the help of a caulk gun. It is usually advised to wait for no longer than 24 hours; 12 hours is best to wait between coats.

Apply another coat(s)

Before applying another coat, you can plug up the ports you filled. Press the layer into the cracks and make sure the crack is filled. You must ensure it looks balanced with the rest of the wall by leveling each coat.

You can then apply 3-4 heavy coats to the exterior walls of your house, and if the cracks appear in the walls of the house’s interiors, you can use 2-3 coats.

Allow the plugged injection ports to cure for at least 5 days before cutting their necks off. You can finish it off by adding texture to the walls using a bristle brush or paint over the wall.

Additional tips when applying basement wall sealer:

There are a few additional tips to follow when you’re applying a basement wall sealer. To start on the right foot and waterproof your basement walls, you can:

1. Avoid long-term exposure to direct sunlight; and some sealers are infused with resin and do not pair well with light. Having the walls face the sun will bring about a change in color, turning their appearance into yellow or brown.

While applying, you should also be cautious of doing it under the hot sun. It would be best if you avoid high temperatures as this may cause the sealer to dry up sooner than you want. This doesn’t allow the material to bond fully, and poor adhesion can chip away quickly.

2. Let the layers dry correctly. Some sealers dry faster than others, and it also depends on whether you use adhesives or sealants. Adhesives serve a more durable feel and are more rigid as compared to sealants which can sometimes be malleable in nature.

So, adhesives take more time to dry than sealants, and they both need proper time to dry before applying another layer of coating. If you do not let the surface dry completely before applying another layer, your filler may peel or not bond properly because of the moisture collection beneath.

3. Do not seal your wall during the rainy season, and this is one of the most important rules to follow. If rain is expected within the next 24 hours, don’t waste your time and material.

Wall sealing can enhance the look of your walls and strengthen them, but if it’s done in a hasty way because of the rain, you can even damage the walls. Avoiding the rain or using protection against it is the best move.

If a wall has cracks and is susceptible to moisture, it may begin rotting. It is very important to make sure the walls are dry, and rain does not touch the crevices when you’re sealing the cracks.

Signs of cracked or leaking basement walls

Keeping a clean and dry basement does not only reduce any health hazards, but also the need for expensive repairs. There can be minor inconveniences regarding water damage, or issues pertaining to moisture. You must prioritize regular checking of the basement and its walls. Here are a few common signs of leakage problems or cracked walls to look out for.

Wet carpet or moist floors

Most houses have electrical wires and pipelines that are fixed inside the walls, and if there is a possibility for your pipes to leak, it can cause moisture in your basement. 

Rain can also be the culprit in this case. Sometimes, the rain gets collected in the ground, and due to poor grading or poor drainage system, some of the water can get accumulated in your foundation and make its way through your basement walls.

If you start noticing wet carpets or moist floors, this can be a warning sign that there is a leakage problem in the house, and it must have also caused cracks in the walls.

Cracked or flaking paint that feels wet to the touch

Perhaps, you did not prepare the surface well when you painted the walls. If your paint surface is dirty or wasn’t primed in the proper way, this can lead to paint cracking and flaking.

When the paint starts feeling damp when you touch it, it may be a sign of leakage in the walls. This could also mean that the walls are exposed to very high humidity so that some hairline cracks will be visible on the walls.

The walls give way to the moisture, and the paint peels. If there’s flaking paint on your walls, it can be an indication of something dangerous. So, be wary if there is any cracked or flaky paint on your walls.


Any kind of moisture attracts mold, so if there is basement moisture, mold will grow in abundance and can even grow through the cracks of the foundation.

Mold is a warning sign of the foundation deteriorating and can even be a problem in itself as there are people who are allergic to mold. If you are one of such people, any contact with mold can lead to congestion, sore throats, headaches, and so on. 

If you notice any type of mold growing on your walls or foundation, it is high time for you to patch them up as quickly as possible. You can prevent any water flow inside the basement and keep the structural integrity intact, killing off the mold for good.

Musty smell

Your basement may contain a musty odor, and it may displease not only you but also any guests you bring over. In case your basement has an unpleasant smell, it is a clear sign of water damage in the house.

Musty odors are a build-up of mold, dew, dust, and anything that attracts moisture to a specific area. It is undoubtedly a leakage problem, or perhaps, water must have entered your basement somehow or the other.

This obviously means there are cracks in your walls, as that’s the only way for moisture to seep through. You can quickly fix the problem by restoring your walls.


Why do basement walls crack?

Basement walls happen to crack if your home is saturated with a lot of water and humidity. There may be an excessive amount of ground humidity owing to the rain as well. This will lead to the expansion of soil and the contraction of the walls against the soil.

Weight of the furniture, constant pressure by body weight, and frequent seasonal changes can affect the building structure. Owing to most of these factors, and additional poor building practices, like not maintaining the house regularly, the walls can crack easily.

How does wall sealer work?

With the use of crack sealants, you can flexibly hide the crack. It can also help in making the cracks invisible to the naked eye and helps the future movement of the cracks by tolerating and stretching to blend into the crack width.

Some epoxy wall sealants can help repair the walls, but some sealants do not fix the structural problem. However, they do act as a waterproof and rubberized compound that fills in all the gaps. If you apply it well, it may completely seal the wall.

Would these sealers work on stone walls?

Yes, sealers do work on stone walls. However, you can’t just use any sealant for that. There are certain sealants that are applicable on stone walls as per instructions placed by the manufacturer. Hence, you’ll have to look for products that specifically mention stone walls as a valid surface for application.

Since, stone walls differ from concrete walls, the application process of the sealant will also vary. It is highly suggested to go over the instruction for application if the application is on a stone wall or surface.

Closing thoughts

Basement sealing can be an easy task, especially with the ready-to-use sealants we have mentioned above. With the help of sealants, you can cut down the high cost of renovations and repairs made due to excess moisture. 

To prevent moisture altogether, it’s always better to get started early in waterproofing your house, especially the basement. Hence, it would be best if you didn’t wait around for an early sign of mold or mildew. 

With the availability of easy-to-use sealants, it provides an opportunity to start a waterproofing project of your own, especially if you have moved into a new house recently.

Interested in a little DIY project? We suggest using the basement sealant from Liquid Rubber. It’s environment-friendly, easy to apply, quick to dry, and won’t dent your pocket after the purchase. 

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