Should I Waterproof My Basement From Inside Or Outside?

Basement seepage is an all too frequent occurrence. Wetness can be caused by the poor construction of basement floors and walls that could have been resolved by either exterior or interior waterproofing. But, should you approach basement waterproofing from the outside or the inside of your dwelling? We've researched both methods of waterproofing to get the best answer for you.

Depending on your budget and structural needs, each of these waterproofing methods has its pros and cons, but will surely save your property from further preventable deterioration. Exterior waterproofing, while more expensive, provides the most efficient water prevention. Interior waterproofing is more affordable and easier to maintain in the long run.

To help you make the right choice to address or, better yet, prevent that source of dampness in your basement, we've created an easy-to-understand guide on the different waterproofing systems consolidated in this article just for you! Read on!  

Protecting the basement foundation outside of a brick house from water and moisture using a foundation waterproofing dimpled membrane, barrier for the exterior walls, Should I Waterproof My Basement From Inside Or Outside?

Basement Waterproofing Methods

Correct and professional basement waterproofing ensures that the integrity of your house–which is one of your biggest investments in life–is not jeopardized by the perennial wet weather conditions. Two of the most common methods of waterproofing your basement are:

Waterproofing From The Outside

worker applies bitumen mastic on the foundation

Though labor-intensive and expensive to carry out, waterproofing your basement from outside provides the most efficient way of preventing water and moisture build-up around the foundation of the house.

Consisting of gutters and downspouts, exterior waterproofing ensures that water is directed away from the main structure. Exterior waterproofing can be undertaken with any type of basement, made either of poured concrete or masonry block walls.

The process likewise entails excavating the soil away from the external basement wall, installing on it a water-resistant membrane, known as a moisture barrier, and constructing a footer drain pipe that will lead the water to an exterior French drain.

Remember that the strength of the basement wall will start to deteriorate as soon as it becomes constantly exposed to moisture and pressure. Keeping the foundation of your house dry with this method is integral to making your home last a lifetime! 

Waterproofing From The Inside

waterproofing for foundation with waterproof membrane and drainage

During heavy or continuous rainfall, water creeps through the porous soil surrounding the basement wall. As it accumulates through time, it creates a greater force–called hydrostatic pressure–against the wall, causing tiny cracks and eventually water leaks.  

To learn more, check out: "Is Basement Seepage Normal?"

Interior waterproofing, which is less expensive and easier to maintain, uses carefully engineered pipes and drains around the perimeter of the basement floor to help prevent excessive build-up of water. The pipes collect water flowing through holes and carry it to a sump pit, a temporary pit where excess water is deposited until discharged using a pump from the basement floor.

Some engineers however observed that not all pipes function well the way they are portrayed in advertisements because of poor installation. Consulting professionals and knowing what is fit for your budget and structure needs are indispensable considerations to avoid this from happening.   

A homeowner might also choose to have vapor barriers made of foil sheets mounted on the interior basement walls to reduce the accumulation of humidity. Another method of waterproofing from the inside.

What is the best product to waterproof basement walls?

 close-up of a metal downspout, roof gutters downspout installed near unfinished foundation, basement covered with a bitumen waterproofing membrane.

There is a wide array of products available on the market that can help strengthen your basement walls’ defense against water leaks and moisture buildup, but some of the best products as reviewed by Breaking Free Mediation are:

  • Liquid Rubber Concrete Foundation Sealant
  • Miracle Sealants 511QT6 511 Impregnator Sealer
  • Ghostshield Siloxa-Tek 8500 Penetrating Concrete Sealer
  • Essential Values Concrete Sealer: Acrylic Emulsion Formula
  • Thompsons Water Seal 24111

How can I waterproof my basement without digging?

Given the high cost of exterior waterproofing, time-consuming excavation it requires, and possible destruction of lovely landscapes, many homeowners opt to do the alternatives instead.

Some basement waterproofing methods without digging include:

  • Crack Injection - This is applied to non-structural cracks. In this process, an expanding polyurethane is injected into ports to fill the crack completely
  • Interior Drain Tile - Also referring to a drainage pipe, drain tiles provide a path for the water away from your home through a sump pump.
  • Crawl Space Encapsulation - Usually used for partial basements (not in full height), encapsulation requires the application of a heavy-duty moisture barrier on the floor of the basement.

Can any basement be waterproofed?

Light grey and spacious basement area with staircase.

Engineers have designed dependable waterproofing methods and made them available for you to choose from, and that means however your basement was constructed, it can be waterproofed. Of course, professional supervision during any construction is a must!

How much does it cost to waterproof an old basement?

The cost of waterproofing depends primarily on the choice and the need of a homeowner like you. Typically, when the water has already accumulated in the basement, the best solution is interior waterproofing, which is generally cheaper.

On the other hand, exterior waterproofing is best undertaken while the house is under construction.  

Depending on other factors such as labor and material costs, location, size of the area, foundation type, existing damage, etc. -the usual cost of waterproofing an old basement according to Home Advisor ranges from $2,255 to $7,284.

Accordingly, waterproofing basements costs between $5 and $10 per square foot.

Thinking of undertaking this project? Check out: "How Long Does Basement Waterproofing Last?"


A suburban residential construction site new basement foundation

Waterproofing your basement primarily stems from a good assessment of what your house urgently needs considering the weather conditions and your financial capacity. Both methods are proven to be effective to save you from unnecessary headaches of fixing property damage due to water seeping through the basement walls.

At the end of the day, all you want is to create a habitable space in the basement–dry, clean, and fresh–for your family and safe storage space for your most treasured possessions.

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