How to Waterproof a Wall From the Inside (8 Steps)

Waterproofing the outside of your walls is common, as it is needed to protect the walls from natural weather conditions. However, is it possible to waterproof your walls from the inside?

Although waterproofing the inside of your walls is nowhere near as common, waterproofing your walls does not have to be limited to the exterior. Waterproofing can be done from the interior and is most commonly done when there is moisture on the interior. There are eight steps to ensure the waterproofing process is as easy as possible.

Waterproofing your walls does not have to be a daunting or expensive task. Professional help is not required, as you can do all the preparation and installment yourself. Your walls can be waterproofed easily just by following the eight simple steps below!

1. Locate The Source Of The Moisture

Although this may seem an obvious step, a surprising amount of people overlook it and waterproof their walls when it is unnecessary to do so. Waterproofing your walls requires time and energy, so you will not want to do it unless absolutely necessary. It is important to locate the source of the moisture on your walls.

2. Conduct A Condensation Test

To determine which course of action is needed, conduct a condensation test. To conduct this test, ensure a small part of the wall is completely dry, leaving no moisture behind. A large part of the wall is not needed, a mere twelve square inch section is all that will be tested. Next, attach a piece of aluminum foil to the wall using tape or by applying pressure to it. After twenty-four hours, remove the aluminum foil. If the foil is damp, then water is coming through the wall from the outside. If it is dry, then the moisture has a different origin.

It is important to know if the moisture has a different origin, because if it does, then it could be fixed by simply installing a vent. If moisture is not coming from the outside, waterproofing your walls could be avoided. All other steps could be unnecessary, as there would be a simple solution to fix the condensation on your walls.

3. Fill The Damages In Your Walls

In order to successfully waterproof your interior walls, you must fill all the cracks and gaps in your walls. Otherwise, all other efforts will be in vain. It is impossible for your walls to be fully waterproof if they have cracks to allow the water to seep through.

Leaks and moisture are common on interior walls if there are unfilled cracks. Fortunately, fixing these cracks is a simple task that anyone can do. By following the steps below, you will be able to effortlessly fill the cracks in your walls.

Fixing Cracks In Drywall

If your wall is made of drywall, then you are in luck. Fixing cracks in drywall is the least challenging task. The best way to fix the cracks is to re-tape its joints. Remove any old tape from the wall and vacuum out any loose debris from the cracks. Re-cover the joints with tape and apply a fresh coat of drywall compound.

After the drywall compound has been applied, allow it to fully dry. After it has dried, lightly sand over the tape and compound. Next, apply another coat of compound and allow it to dry for twenty-four hours, or until it is fully dried.

Repeat the process of applying drywall compound and sanding until your cracks are completely filled and your walls are smooth. At least two applications of drywall compound are recommended, although three may be needed.

Fixing Cracks In Concrete Walls

Fixing cracks in concrete walls is more complex compared to drywall, however, this is no reason to give up. Cracks in concrete walls can also have a simple fix if the steps below are followed:

To fix the cracks in concrete walls, first purchase an epoxy kit. You will need to vacuum out any loose material and debris from the cracks. Next, you will use nails to align the injection points. Tap 3-inch nails into the crack, spaced 12 inches apart from one another.

Epoxy kits typically have two parts, A and B. A is the resin side and B is the hardener. Mix equal parts of A and B from the epoxy kit. Spread a small amount of the mixed epoxy onto each injection port. Slide the port over one of the nails and attach each port against the wall. Next, apply a larger amount of mixed epoxy to completely cover the crack.

Next, use a caulk gun and fill all of the ports with liquid concrete repair. Ensure all of the ports are completely filled and do not stop until they are starting to slightly overflow. After the liquid concrete repair has set for five days, cut the necks of the ports.

4. Fix The Deep Cracks

Fixing large and deep cracks may sound intimidating. However, by following the simple tutorial below, you will be able to fix the deep cracks in your walls with no problem.

“If cracks in drywall or plaster are deeper than a 1/4 inch, you will have better success if you first fill the crevice with a filler compound prior to taping with joint compound. Mix the compound as per the manufacturer’s instructions. Fill the crack until it is flush with the existing wall. Cover with tape and joint compound to achieve a smooth wall”. Source: HomeGuides

5. Use Sealer

Sealer is used to make walls water-resistant. Although a sealer will not be successful in fully waterproofing your walls, it can aid in the process. The sealer has an easy application, as it is applied just as paint would be.

Sealer protects walls from a number of pesky problems, such as chipping, cracking, and thankfully water damage. A sealer can be a tremendous help in waterproofing your walls, and it should not be overlooked just because it is not fully waterproof.

The following sealers will be able to make your walls water-resistant. Below is a list of the best sealers to use for your walls, in price ascending order:

1. The Zinsser Gardz Damaged Dry Wall Sealer can be purchased at AceHardware for only $9.99. This is the perfect sealer for you if you have drywall, and it has a perfect rating of 5 out of 5 stars.

2. The Rx-35 PRO-999 1 gal. Interior Drywall Repair and Sealer Primer can be purchased at HomeDepot for $19.98. This sealer is great in preventing water damage and has a rating of 4.4 out of 5 stars.

3. The Drylok 28613 Extreme Masonry Waterproofer can be purchased at Lowes for just $32.98. This sealer has a fifteen-year warranty and has an almost perfect rating of 4.7 out of 5 stars!

6. Use Water-Resistant Drywall

Water-resistant drywall is a great alternative to standard drywall. If you use water-resistant drywall, then you are already well on your way to waterproofing your interior walls.

The following drywalls will be able to make your walls water-resistant. Below is a list of the best drywalls to use for your walls, in price ascending order:

1. The Sheetrock Brand UltraLight Mold Tough 1/2 in. x 4 ft. x 8 ft. Gypsum Boards are sure to satisfy your needs. This water-resistant drywall is the lightest option and is encased in one hundred percent recycled moisture and mold-resistant paper. This drywall can be purchased from HomeDepot for only $13.64, with a rating of 4.6 out of 5 stars.

2. The 5/8 In. x 4 Ft. x 8 Ft. Moisture Resistant Drywall says all it needs to in its name! This drywall is moisture resistant and is a perfect option. This drywall can be purchased from ShellLumber for only $15.99.

3. The 5/8 in. x 4 ft. x 8 ft. Mold Tough Firecode X Panels are great for the interior of your home. These panels resist water, prevent fires, and prevent mold. They can be purchased from BuildClub for $18.90.

7. Install A Sump Pump

Drainage systems are a sure way to keep moisture out of your walls. Two common types that are used for interior walls are sump pumps and French drains.

A sump pump is especially common when it is being used for basements. This drainage system works by using centrifugal force to pump the water inside of the sump pit and ridding the water from your interior walls. Put simply, a sump pump pulls water away from interior walls and sends the water outside.

8. Install A French Drain

A French drain guides water away from interior walls. Exterior and interior French drains are available. Below is a tutorial in installing an interior French drain, in order to waterproof your interior walls:

“An interior French drain is installed by removing a strip of concrete floor around the perimeter and digging a shallow trench to the base of the footings.  A bed of washed gravel is poured and perforated, corrugated plastic pipe, wrapped in a filter “sock,” is laid on top and connected to a sump basin.  More gravel covers the pipe and the concrete floor is replaced”. Source: USWaterproofing

If French drains are used in concurrence with sump pumps, then your interior walls are sure to be waterproof. There will be no need to worry about the moisture on your walls ever again!

Ricky Kesler

With all of the projects I've done over the years, you'd think that I work on my house full-time. But I actually enjoy other things like spending time outdoors and time with my family.

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