Typical Basement Waterproofing Methods

Interior Sealants

Interior sealants are an effective way to waterproof basement walls and floors. The most common entry points for water seepage in concrete foundations are cracks and openings where pipes penetrate the foundation walls. Sealants work by sealing these cracks and gaps.

Two main types of interior basement sealants are epoxies and urethanes. Epoxies are very strong adhesives that can be applied directly to cracks and openings. Urethanes can be pressure-injected into cracks and voids in the concrete.

Using interior sealants prevents humid interior air from penetrating the porous concrete and leading to further cracks and damage. Sealants also block water from seeping in through foundation cracks due to hydrostatic pressure or heavy rains.

Applying an interior sealant to basement walls and floors is often one of the best waterproofing solutions, especially for preventing moisture migration through the concrete. Be sure to address any exterior drainage issues as well for comprehensive waterproofing. Interior sealants provide an extra barrier against water intrusion and humidity for drier, more usable basements.

Exterior Basement Waterproofing

Exterior waterproofing is an effective approach to keep basements dry and prevent water damage. This method involves applying waterproofing materials to the outside surface of foundation walls. Popular exterior waterproofing solutions include:

  • Polymer coatings - Polymer-based waterproofing products can be sprayed directly onto the concrete foundation. They cure quickly to form a waterproof barrier and are durable enough to last the lifetime of the structure. Polymer coatings are not degraded by the pH of the surrounding soil.
  • Membranes - Waterproofing membranes made of materials like rubber, asphalt, or synthetic polymers can also be adhered to the exterior foundation walls. These continuous sheets block moisture from seeping into the basement.
  • Drainage boards - Drainage boards or dimple boards are sometimes applied on top of exterior waterproofing. These textured panels help direct groundwater away from the foundation through drainage pipes.

Exterior waterproofing seals out water before it can enter the foundation walls and cause structural issues like cracks or shifting. For maximum basement water protection, exterior coatings and membranes can be combined with proper exterior grading and drainage.

Interior Basement Drainage System

Installing an interior drainage system is an effective method to manage water buildup and prevent flooding in a basement. This involves creating a drainage channel around the full perimeter of the basement, positioned next to the foundation footers.

Plastic PVC piping or other specialized drainage panels can then be fitted into this channel to direct water away from the foundation walls. The pipes lead to a sump pump that ejects the water outside.

Once the drainage pipes are in place, the channel can be covered over with new cement to create an interior drainage network under the basement floor. This system catches any water that seeps in through basement cracks or permeable foundation walls and diverts it away before it can pool.

An interior French drain or other drainage system handles water intrusion issues and prevents future cracks or damage. By controlling water inside the basement, an interior drainage network is an effective basement leak repair solution.

Interior Basement Waterproofing

Using interior basement waterproofing coatings on walls and floors is an effective solution when condensation is the main cause of minor dampness or seepage. These coatings create a waterproof barrier that prevents humid interior air from penetrating porous concrete surfaces. This condensation control can address minor moisture issues.

For more serious water intrusion through cracks or the foundation, interior basement waterproofing may not be sufficient. Installing a backwater valve on the main sewer line can help prevent sewer backup flooding, but doesn't address actual water leaks.

For comprehensive interior waterproofing against leaks, a full interior drainage system is required. This complex solution involves installing a drainage channel around the basement interior linked to a sump pump. Drainage pipes behind walls or under floors collect incoming water and divert it away from the foundation.

While interior coatings help control humidity and condensation, substantial basement leaks need an integrated drainage system for full interior waterproofing. This interior drainage approach manages water buildup and leak points inside the basement for a dry, usable space.

Foundation Crack Repair

Injecting sealants into foundation cracks is an effective basement leak repair method that can be done with minimal disruption. Cracks in poured concrete basement walls commonly form due to shrinkage or shifting of the foundation. If left unaddressed, these cracks allow water to seep into the basement.

Specialized injection sealants like epoxy resins can be pumped into cracked concrete under pressure. The liquid sealant penetrates deep into the foundation crack and bonds the concrete surfaces back together while sealing out water.

Epoxy injections provide a structural repair by gluing cracked sections of the foundation wall together. Other waterproofing sealant injections may just fill the void without bonding.

Because the concrete does not need to be replaced, foundation crack injections stop basement wall leaks with minimal demolition. This targeted repair technique seals cracks at their source and is less invasive than exterior excavation or interior drainage work. Overall, injecting cracks is an efficient way to repair basement leaks. Monitoring for new cracks and maintaining drainage is also recommended.