Learning How to waterproof basement walls is one of the most practical DIY savings projects homeowners can take on themselves.
If you’re dealing with a wet or musty basement and trying to figure out how to solve the issue yourself, follow these five simple steps to waterproof the inside walls of your home.
You’ve probably encountered many articles on waterproofing a basement or advertisements for basement wall sealers claiming they will rid your home of unwelcome moisture. But do they work?
In many cases, waterproofing the inside of basement walls is the first, best, and by far the least expensive option.
If water is seeping through the block or concrete walls in your basement, Follow Our step-by-step waterproofing Guide. Once you’re completed, you should have a fully dry basement again.
How To Waterproof Your Basement (5 Steps)
Step 1: Determine “Where the Basement Water is Coming from”
Your first order of business – Is to determine the Source of the moisture leak.
A). Look for Cracks in Basement Walls:
Inspect all the exposed concrete basement walls inside the home – from floor to ceiling.
Look for any hairline cracks that allow outside moisture to penetrate, and mark the location with dry chalk or painter’s tape. This will allow you to quickly locate and patch each wall crack before patching the walls.
B). Look for Wet Spots on Basement Walls:
Tips & Tricks to Discover Sources of Water Leaks:
For wet or wet-stained walls without cracks, you can quickly determine the cause of the leak by taping a piece of aluminum foil (about one sq. ft.) to the inner side of your basement walls and leaving it there for 24 hours.
Examine Leak Test Results:
- 1) If you find water condensation on the Outside surface of the foil, then you’re dealing with high humidity inside your basement. Alternatively, waterproofing products can fix such a problemby using a portable room dehumidifier or installing a whole-house dehumidifier system.
- 2) If you find condensation on the inside surface of the foil, water seeps through the basement walls from the outside. The wetness is likely coming from improper drainage around the outside of your foundation walls.
- In this instance, the soil around your house has a high water table, pressing against the outside of your basement walls. The most logical solution is to provide suitable drainage outside to avoid high rainfall or unusual flooding in your area.
- This issue may eventually need to be addressed, which we address at the end of this article: “How to Waterproof Walls from the Outside.”
Step 2: Prep Walls (Before Applying Waterproofing)
Use a stiff brush to remove loose impediments, dirt, or cobwebs from the walls. In addition, You may notice some white stains on the surface of concrete or masonry walls.
This is called efflorescence, a powdery substance left from salt pushed through the masonry wall from the outside ground.
This powdery substance prevents waterproof paint and sealer from adhering to concrete or masonry. To neutralize efflorescence before you waterproof walls, use Drylok liquid or Drylok powder etch first.
Step 3: Fix Wall Cracks From The Inside
Now that you’ve determined how the water gets inside, it’s time to fix your leaky basement walls.
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Fill Cracks in Walls:
First, repair all basement wall cracks up to 1/4″ wide (See Step 1) using a top-brand epoxy wall crack sealer.
- We recommend PC Products crack sealer because it is a highly rated, affordable, and permanent concrete crack sealer. PC Products includes one tube of two-part epoxy and is delivered efficiently to cracks with your standard caulk gun.
- Note: If you have wide basement wall cracks exceeding 1/4″, install concrete wall crack plug material such as Drylok Fast Plug. This product can even stop water under pressure from the outside.
Step 4: Buy the Right Waterproof Basement Wall Sealer
Depending on the condition of your basement walls, the severity of cracks, or whether your basement walls have been previously painted, you must determine the best concrete wall sealer for your particular situation.
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Using Waterproofing Paint for Basement Walls:
Waterproofing paints: These are expandable acrylic formulas similar to regular paint. You apply them in a much thicker layer by rolling, brushing, or spraying.
Of all the good “paint” products on the market, our first choice is KILZ Interior/Exterior waterproof paint – white from Amazon. It is easy to apply and water-based for simple clean-up.
Get Enough product! – One gallon only covers 100 square feet. A close second material, but slightly more expensive, is the Drylok Waterproof paint for the interior or exterior, which is White.
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Using Silicate-Based Concrete Sealer for Basement Walls
Also known as a densifier, silicate is a mineral sealer that will dry with a “Clear” transparent finish and is therefore only suitable for virgin concrete walls (walls that haven’t been painted or sealed before). One of the best silicate-based wall sealers on the market is the Siloxa-Tek 8500 product from Amazon.
This ready-to-use pre-mixed gallon covers 250 square feet (10 ft. x 25 ft.) of wall.
Silit sealers work by chemically reacting with specific components of concrete or brick, forming a solid, waterproof surface. Apply silicate-based sealers with a roller, brush, or sprayer. It’s relatively simple and won’t peel or flake off.
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Use Concrete coatings for Basement Walls:
If you have done extensive wall crack repair, you may wish to conceal all the patches with a concrete coating. Concrete coatings are cement-like coatings that stick permanently to concrete and masonry walls once they dry.
Apply this product using a heavy brush (preferably with Tampico bristles). Swirl the brush at the end to smooth out the final look. We recommend looking at Floor Tex 40 from Seal Krete.
Step 5: How to Apply Waterproofing Sealer to Walls
Once all wall cracks have been filled or patched, you can begin waterproofing your basement’s interior block or concrete walls—this is one of the most straightforward parts.
Note: If you have applied any crack sealer or patch material, allow at least 4 hours of curing time before applying a waterproof sealer or paint to the walls.
These are the three application methods for Waterproofing Basement Walls:
- 18″ (or standard 12″_ Paint Roller/Pan (To paint roll the walls)
- Four ft. paint pole (attaches to paint roller)
- 3″ Wide Paint Brush (to trim the perimeter)
- Painter tape (if masking off the perimeter)
- Spray gun/compressor (optional)
In most cases, we recommend using a combination of a 3″ paintbrush and a wide paint roller with a paint pole attachment – when applying the basement wall sealer.
After putting on disposable paint gloves, start the painting process with a 3″ wide paintbrush by cutting in the paint at the floor lines and top of the basement walls.
Follow that step by using the paint roller (fill in the box), overlapping rows, and completing these steps for each wall of your basement.
Optional Paint Spray Method: If you have paint spray equipment and expertise, you may additionally choose to use a professional paint spray gun and compressor.
However, the best basement wall seal products, especially paints, are thicker than regular latex paint.
Waterproofing Walls from “Outside” of Home
If you still find moisture intrusion after sealing basement walls inside your home, you need to consider removing the water penetration outside the walls. This is the surest way to eliminate water intrusion in more extreme circumstances.
However, it is not the cheapest way to waterproof, and depending on the size of your project, it can cost up to several thousand dollars.
This option involves installing a waterproof coating outside the basement walls, drainage tile, and a sump pump to evacuate the high water table.
Moreover, it requires professional help and equipment since it involves digging around the house to reach the full depth of the foundation wall.
Conclusion
Here’s our detailed guide to waterproofing basement walls. Remember, none of these solutions will work efficiently unless the cracks and gaps in the walls are properly sealed.
So make sure you use generous amounts of product to fill the cracks and gaps before you seal basement walls.
Frequently Asked Questions (FAQ)
Can you Seal the Basement “Floors” with “Wall” sealer?
You can seal basement floors with any good waterproof sealer for basement walls.
However, if you’re using “white” basement waterproof paint for walls, you should get waterproof sealer tinted (gray or brown) first to hide foot traffic and dirt on Floors.
Does Waterproof Paint stop water from coming into the Basement?
Waterproof paint or sealer for concrete will help prevent moisture on solid concrete and masonry basement walls, but it will not stop water intrusion.
If you have cracks in basement walls, you must first plug or fill the wall cracks before applying basement waterproofing paint or sealer to prevent water intrusion.
Can I Waterproof the Basement Walls Myself?
If you have minimal do-it-yourself skills and use our how-to waterproof basement guide to waterproof walls inside your home, you should be able to handle this task easily.
Doing this job yourself is one of the cheapest ways to build equity into your house and protect your home furnishings.
Video: How To Waterproof Basement Walls with “Drylock”
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