Here’s How to Seal Your Home’s Foundation

Kenneth Wilson

When it comes to any construction job, a solid home foundation is essential. While you can take numerous measures to guarantee that your foundation will last as long as your home, one vital way of keeping it functional through the years is by sealing it.

If your foundation isn’t properly sealed, moisture can penetrate your house through the foundation walls and floor. This moisture can create issues such as mold development and contribute to a range of health concerns. Knowing more about foundation sealing can help you understand the problems that might arise if you do it incorrectly and what you can do to repair existing foundation problems in older buildings.

Most homeowners and property owners refer to "sealing a foundation" as a thick layer of asphalt-modified polyurethane (called the foundation sealer) applied to the foundation built to keep water out from walls. Exterior waterproofing membranes work well on both poured concrete and masonry foundations, and installing one to prevent leaks is typically a good idea.

You’re probably already deciding on sealing your foundation to protect it from further water damage! But before you do that, you should first watch out for the signs that will tell you it's truly time for you to seal your foundation, as well as what may be causing those uninvited water leaks in your basement.

Indicators for When You Need to Seal Your Foundation

Water infiltration is one of the most distressing things that can happen to a house. The structural damage that water can inflict is severe, the health risks connected with mold are substantial, and the danger of future damage to your house is inevitable.

Once water has entered your house, it will cause damage and you’ll end up needing to replace your insulation, drywall, and, based on the extent of the damages, framing.

Here are few things that you need to look out for: 

  • Stains on the floor or on the walls caused by water
  • Leaks from the floor or the walls
  • Doors that have swelled or are distorted
  • Condensation on doors and windows in the basement
  • Accumulation of water puddles in the basement
  • The stench of moisture that refuses to leave
  • Mold or mildew must be seen to be confirmed
  • Cracks on the floor or on the walls

In the worst-case scenario, your home's foundation could get damaged if a water leak has stayed undiscovered for a long time or if moisture concerns have not been properly handled.

Getting Assistance for Foundation Sealing

While a lot of people have considered doing a D.I.Y. project for sealing their foundation, we advise you to call professionals for these main reasons: 

Reason # 1

It is hard to acquire the necessary materials without the assistance of a professional. We cringe every time we see people use alternatives like roofing tar or plastic sheeting in "sealing" their basements because the endings are always very horrific. Professional polyurethane is a specific substance designed for soil contact that will not degrade over time like consumer polyurethane.

Depending on the scenario, heavy-duty drainage board and insulating material may also be needed. A roll of Visqueen just won't cut it. Most of the time, professionals get foundation sealer and other supplies from direct suppliers that are only available to the circle of people who work in the field.

Reason # 2

Sealing a foundation takes a lot of time and effort. The procedure begins with the removal of everything in the affected area that is next to the home, such as decks, patios, walkways, and planters – and then the actual work begins.

Adding to that, the entire foundation wall must be dug out to a depth of up to eight feet in order to install the membrane, and the trench must be wide enough to work in. Oh, and because it's so close to the structure of the home, all digging will have to be done by hand.

Reason # 3

Assessing if a drain tile is needed or not can only be done by a professional. It's possible that drain tile will be required. When laying the waterproofing membrane, a specialist may analyze the groundwater status and indicate if the foundation would benefit from placing outside drain tile. Even if a homeowner could estimate right, they would still have difficulty in installing it appropriately.

Reason # 4

Even if you're willing to do the work, it will take a significant amount of time. Even with a few capable assistants, the excavation process can take days. The excavation must then be backfilled once the wall has been properly cleaned. Alongside this, the membrane is applied and allowed to set before the drainage board or insulation can be placed. Also, that isn't even taking into account the removal of external buildings.

Benefits Of Using A Waterproofing Foundation Sealer

Extending the Life of Your Walls

Consistent leaks erode the strength of your concrete walls. As a result, they will fall apart in no time. Water sealant paints can manage all seepages except interior leaks. This will protect your foundation by keeping it dry, providing healthy, long-term protection through the years.

Waterproofing Paints

Many water pipes are covered by cellar flooring. As a result, you'll almost certainly find it wet on a regular basis. Water-repellent paints can prevent water from leaking through your walls and flooring. However, it only works on a wet surface that has had some moisture problems, not on a flooded basement.

Promotes Resistance To Mold and Mildew

When you allow your basement walls to become extremely damp, molds and mildews grow. The advantage of utilizing water sealing paints for basement walls is that they prevent the walls from becoming moist. As a consequence, no exposure implies no growth of molds or fungus.

Water Diffusion Prevention

If you look closely, your basement’s walls and floors are permeable. When you use waterproofing stains on the floors and walls, you fill all of the pores. This eliminates the sources of vaporization, resulting in dry basement walls and floors.

Things to Consider Before Buying Waterproofing Foundation Sealer

We recommend that you leave sealing your foundation to the professionals because you may cause more damage if you do it on your own. However, if you want to be more involved in the process, whether it’s doing it on your own or checking out the materials that your contractor will use, here are some tips you can follow to make your suggestions more informed. (Related: The Best Waterproof Paints For Your Shower That You Can Buy Today)

Intended End-Product

Different kinds of sealants are better at different jobs. For example, the sealant you use to guard against dirt and temperature changes will most likely be different from the sealer you use to waterproof. There are numerous multi-use coatings on the market, so you should be clear about which features you want and which you do not.

Process of Sealant Curing

You may encounter some issues with curing periods depending on how and where your sealants or coatings are set. Some coatings require specific equipment to cure for long periods of time, while others cure fast at ambient temperature. The cost of each choice will most likely reflect the amount of effort required to cure the sealants properly.

Cleaning of the Surface

You'll need to pay special attention to how your surfaces are prepped prior to treatment. If you want the caulking or sealant to stick to the surface without flaking afterward, you'll need to clean it well. You may have to take extra procedures to guarantee this depending on the type of coating existing on the material, painted or not.

Types of Sealants

Epoxy coatings, which offer a glossy, long-lasting finish and protect surfaces, are pretty popular. There are also other polymers designed for industrial use, such as silicone, acrylic and polyurethane. Always consult a specialist to determine what sort of sealant is most commonly used for your intended purpose, as well as any brands or variations that are best suited to your requirements. A coatings specialist can help you choose the correct product and save you money in the long run, all while ensuring that your sealants are properly placed and will perform as expected in any climate.

Best Basement or Foundation Sealers in the Market According To Experts

D.I.Y. Leaky Basement Wall Crack Repair Kit

For homeowners that wish to do their own basement repair, the D.I.Y. leaking basement wall crack repair kit is an easy-to-use foundation crack repair kit. The fix is excellent against leaky basement wall fractures and provides a long-term remedy for keeping water out of these gaps.

It has a polyurethane (low viscosity) that may be injected directly into fractures. Because it does not involve drilling into the concrete, homeowners may inject a normal chalk gun from inside the foundation wall.

  • No drilling is required.
  • Low-pressure repair for concrete cracks
  • User-friendly
  • To seal the fracture, you must expose the whole surface.

Xfasten Fiberglass Waterproofing Fabric Tape

The waterproofing membrane mesh on the XFasten fiberglass waterproofing fabric tape may give up to 40 years of severe waterproofing. Not only that, but the tape also keeps additional moisture sources from entering your walls and floors.

Even when bent at severe angles, the product creates a water barrier of the proper thickness and resists fracture. As a consequence, even novice homeowners can use the tape without a problem.

The tape is versatile and easy to cut and apply, despite its great durability. The cloth is also compatible with the most popular waterproofing polymers, making it extremely flexible.

  • Waterproofing polymer that is widely used is compatible with this product.
  • Simple to set up and maintain
  • It comes with a huge roll
  • It cannot be folded

Liquid Rubber Waterproof Sealant

The Liquid Rubber Waterproof Sealer is an environmentally safe sealant that includes no solvents, hazardous odors, or V.O.C.s. Because of this, it may be utilized without any specific breathing equipment without risk of contaminating anything.

The sealant's design is inspired by the basic design of paint that requires minimal effort when it comes to application and finishing. You may apply the sealant using a roller or a brush and then shut the container to save the excess substance for another use. Basements, concrete, foundations and roofs can all benefit from the product.

  • Eco-friendly
  • Can be used again
  • Easy to use
  • The instructions on the can don’t give enough detail.

RandonSeal Plus Deep-Penetrating Concrete Sealer

The RandonSeal Plus Deep-Penetrating Concrete Sealer prevents water vapor, water spillage, radon gas, and efflorescence from entering the basement through the floor or walls by seeping through up to four inches of the concrete and internally sealing it.

It also blocks the capillaries and micro-pores in the concrete to prevent efflorescence, radon gas, water spillage and water from entering the basement through the walls or floor. It protects the concrete by hardening and strengthening it, as well as reducing crazing and dusting.

Furthermore, the breathable product doesn’t retain moisture. Plus, it’s non-toxic and contains no volatile organic compounds (V.O.C.s).

  • It strengthens and hardens concrete.
  • Environmentally-friendly
  • Seals the concrete matrix internally
  • The material is too thin.

RandonSeal Concrete Foundation Crack Repair Kit

The RandonSeal Concrete Foundation Cracks Repair Kit is another RandonSeal product that uses an injection technique that is low-pressure so you don’t have to drill holes in your basement’s flooring and walls. It has low viscosity and is two-component, featuring an injection urethane for hairline crack repair.

Because no holes need to be drilled before usage, this kit saves you money that would otherwise be spent on excavation. Plus, it requires no specific equipment and provides a long-term solution for avoiding water vapor, soil gases, and water seepage. It's a waterproofing sealant for the basement.

  • There are no specific tools necessary.
  • You don’t have to dig.
  • Excavation costs are reduced.
  • The instructions are complicated.

Costs of Foundation Sealing

The expenses included in waterproofing a basement depend on different factors, the most important of which is the size of your property. Basement waterproofing expenses, including labor charges, range from $3 to $10 per square foot on average.

According to HGTV, basement sealing costs between $500 and $1,000. The cost of filling a foundation fracture ranges from $250 to $800. Expect to pay between $2,000 and $10,000 for more significant properties or situations with more severe damage. If drainage is the issue, downspouts and gutters can cost anywhere from $3 to $40 per linear foot to replace.

The Verdict

Protecting your foundation is critical to maintaining the structural integrity of your home. Unfortunately, traditional concrete foundations are not waterproof. Water can quickly penetrate your foundation and cause mayhem for even the fanciest and strongest of homes. To ensure your foundation remains solid and to avoid tens of thousands of dollars in repairs, make sure it's sealed, whether you go the DIY route or get it done by the pros (again, we recommend the latter!).

Kenneth Wilson
September 8, 2021

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done. I also operate remodeling design service for homeowners.

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