A leaky basement can damage your home, including destroying possessions, letting mould grow, and weakening the foundation. To stop this, homeowners must decide whether to waterproof the basement from the inside or the outside. Both have pros and cons, and the best depends on your situation. We’ll guide you through the differences between interior vs. exterior basement waterproofing so you can make an informed choice for your home.

What Is Interior Basement Waterproofing?

Interior basement waterproofing is a way of addressing problems with leaks and water in your basement. It serves as a wall to keep water out of the living area and control any water that has already gotten in.

Here are the key steps involved in waterproofing basement walls from the inside:

A waterproof membrane covers the inside walls and foundation floor. This membrane acts as a wall, preventing water from entering the concrete floor and walls. The membrane can be made of waterproof coatings, sealants, or Polyurea Hot Spray Waterproofing membrane to seal your basement walls and floor.

A drainage system collects water that gets past the membrane or through foundation cracks. It includes a sump pump and trenches dug outside the basement. The trenches gather water, which is then sent to the sump pump. When water builds up in the sump pump, it lifts it and sends it away from the foundation, usually through a drain pipe outside the house.

Depending on the situation, an interior waterproofing system might have extra steps added to it. Some of these are:

Filling in holes and cracks in walls: To prevent water from entering, foundation wall cracks can be filled with sealants or epoxy injections.
Dehumidification: A dehumidifier can help keep the basement dry and stop mould from growing.

What Is Exterior Basement Waterproofing?

Exterior basement waterproofing is a preventative method for fixing leaks by keeping water from reaching the foundation.

Here’s a breakdown of the typical steps involved in exterior basement waterproofing:

The first step is to carefully dig out the ground around the foundation, usually down to the footing, which is the base of the foundation wall. This makes it possible to waterproof basement walls from the outside.

After being dug up, the foundation walls are cleaned well and checked for any holes, cracks, or other problems. Cracks are usually fixed with sealants or epoxy injections to ensure the surface is smooth and doesn’t leak.

A high-quality waterproofing membrane covers the outside foundation walls. As a barrier, this membrane keeps water from getting through the concrete and into the basement.

A drainage system is installed around the foundation to collect and move any water that builds up near the foundation’s walls. This system usually includes perforated drainage pipes along the base of the foundation walls, with gravel around the pipes to help collect water. The drain pipes slope away from the house, sending the water that builds up to a sump pump for drainage.

After installing the waterproofing membrane and drainage system, the soil dug out around the foundation is carefully restored. The backfill is packed in layers to ensure the foundation walls are properly supported and to prevent the ground from sinking. Landscaping and restoration work are completed to blend the repaired area with the surrounding landscape.

What’s the Biggest Difference Between Interior vs Exterior Waterproofing?

The main difference is where the membrane is placed to deal with the water problem.

Waterproofing the basement from the inside stops water already seeping into the basement. On the other hand, waterproofing the outside stops water from getting to the foundation.

How To Decide If You Need Exterior Vs Interior Waterproofing?

The ideal waterproofing method depends on several factors:

Severity of Leakage: Waterproofing the inside might work for minor leaks. However, waterproofing the outside is generally recommended for severe leaks or foundation cracks.
Budget: Most of the time, waterproofing inside is cheaper than outside.
Property Considerations: Exterior waterproofing might not be possible if there is limited access around the house or if the foundation is not stable.

Can You Waterproof a Basement from the Inside?

Yes, you can waterproof a basement from the inside, and there are two approaches:

Professional Installation: A qualified contractor can install a full interior waterproofing system that includes a sump pump, a waterproofing membrane, and a drainage system. Professional installation ensures the system is installed correctly and will work well for a long time.
DIY Methods: DIY efforts like painting the basement walls with sealant paint might temporarily stop small amounts of water from seeping in. However, these methods might not work for long-term waterproofing or fixing major leaks.

Can You Waterproof a Basement from the Outside?

Yes, waterproofing a basement from the outside is also an option, with both professional and DIY methods:

Professional Installation: A professional contractor can dig out the foundation, put down a good waterproofing membrane, set up drainage systems, and properly fill in the hole that was made. This is the best and most long-lasting way to solve the problem.
DIY Methods: DIY exterior waterproofing is complex and requires specialized skills and equipment. It’s not a good idea for most homeowners because it could be installed incorrectly and damage the foundation.

Still Not Sure? Call the Professionals!

When choosing exterior vs. interior waterproofing, you should carefully consider your situation. Hiring a qualified professional is the safest and most reliable way to ensure effective and long-lasting basement waterproofing for most homeowners. Waterproof Basement has over 15 years of experience in the industry.

We guarantee the quality of our work and offer a 25-year transferable warranty on our services. Contact us today for a free foundation inspection and a personalized quote to give you a dry and healthy basement for years.

Waterproof Basement from Inside or Outside? Understanding Interior vs Exterior Waterproofing

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