Understanding the Risks
Basements are frequently the most susceptible parts of a building to water damage due to their below-ground location and immediate contact with soil. This soil can release absorbed water during precipitation or snowmelt, finding its way into basements through crevices or leaks. Astonishingly, water can even seep through solid concrete walls through capillarity—a phenomenon where liquid spontaneously ascends in confined spaces or porous materials. A damp basement can lead to several issues including toxic mold, structural decay, foundation failure, and termite infestations, affecting even the indoor air quality due to soil-released gases.
General Approaches for Waterproofing
Effectively waterproofing your basement can dramatically reduce moisture-related damage. Both homeowners and inspection professionals should be familiar with basic leak and flood prevention methods.
Divert Water from the Foundation
The first line of defense against water infiltration is directing water away from the foundation. Faulty roof drainage and poor land grading, often due to defective gutters, are common culprits behind basement dampness. Remedying these issues will largely keep water at bay. Here are some strategies:
- Ensure gutters and downspouts are well-maintained and direct water at least 10 feet away from the structure. Water should flow away, not pool near the foundation.
- Landscape grading should slope away from the building over a distance of 10 to 15 feet, leveling any depressions that may collect water.
- In sloping conditions, utilize shallow ditches or swales that lead water away from the building, emptying into another swale that directs it around the property and away from the foundation.
Seal Cracks and Holes
If moisture is seeping into your basement, it’s likely coming through minor cracks or openings, which could be due to various reasons like shoddy construction, house settling, or exterior water pressure. Fixing these will curtail leaks and floods.
- Locate potential entry points by inspecting the basement for wet spots, discoloration, or leaks.
- For minor cracks, use an epoxy-latex cement mixture, effective for sealing small gaps.
- For larger cracks exceeding 1/8-inch, employ a mortar mixture of one part cement and two parts sand, pressing it into the crevices to remove any air pockets. If exterior water pressure is an issue, a dovetail groove should be cut along the crack before applying the mortar.
Final Sealing with Sodium-Silicate
Once all the preliminary steps have been completed, consider applying a waterproof sealant as a final layer of defense.
Sodium silicate, a water-based substance, penetrates up to 4 inches into concrete and masonry, reacting with their lime components to create a crystalline structure that fills microscopic gaps. This makes the substrate denser, effectively blocking capillary action.
- Handle sodium silicate cautiously, as it can irritate skin and respiratory systems.
- Apply only to clean, bare concrete or masonry surfaces.
- Use a garden sprayer, roller, or brush for application on a slightly damp surface, applying multiple coats and waiting 10-20 minutes between each coat. Wipe away any excess to prevent residue formation.
By taking these measures, you can considerably lower the risk of water-related issues in your basement, thus ensuring the longevity and safety of your structure.