How to Troubleshoot a Wet Basement

Take care of water seeping into the basement before it damages stored items or fills the family room with mildew. Controlling the water's source is always preferable to attempting to block its entry. You can fix the vast majority of wet basements by controlling roof water and surface drainage.

Difficulty: Challenging

Instructions

Things You'll Need:

• Hydraulic Cement
• Brick Or Pointing Trowel
• Fill And Topsoil
• Garden Hose And Nozzle
• Grass Or Ground Cover
• Digging tools, iron rake and wheelbarrow
• Foundation coating, backfill and applicator or brush
• Pressure washer, scraper, steel brush, compressed air or other wall-cleaning tools

Evaluate the water's source

1. Observe when water enters: If it occurs within an hour or so of heavy rain, the cure lies in controlling surface and roof water.

2. If seepage happens only after days of heavy rain, the problem may be a swelled aquifer. If leaks persist for several days after the rain stops, the source is likely related to the presence of a high water table (the top of an aquifer), an uphill spring or a perched water table (a small underground pond). A rising water table usually penetrates everywhere at once. Springs and perched water tables may enter along one wall.

3. If water is unrelated to either the weather or seasonal changes in the water table, it might stem from a broken water service. Test this by shutting off the house main and observing the meter at the street, or contact the local water utility for assistance.

Correct an improper grade

4. Scrape away loamy topsoil, then add soil or rearrange dirt as needed, using digging tools, an iron rake and a wheelbarrow. The grade should slope away from the foundation at least 1 inch per foot (2.5 cm per 30 cm) for a distance of about 3 feet (1 m) minimum but preferably 10 feet (3 m), and leave at least 8 inches (20 cm) of foundation exposed under the siding, more in snowy climates.

5. If this involves a great deal of work and transplanting, consider having a professional excavator and landscaper do the work.

6. Plant grass next to the foundation and locate planting beds 5 to 6 feet (1.5 to 2 m) away from the building; or plant ground cover with a thick root system (which draws water out of the soil) rather than putting mulch (which holds water in) around the foundation.

Seal foundation cracks and holes

7. Excavate the area to access the crack or hole from the outside.

8. Use a pressure washer, scraper, steel brush, compressed air and/or other approaches and tools to clean the wall area in and around the leak thoroughly.

9. Use a brick or pointing trowel to pack large voids with hydraulic cement, which you can apply to a wet surface. When it dries after a few days, brush on foundation coating and backfill.

Tips & Warnings

• To clear a clogged foundation or footing drains, if clean-outs (access pipes that allow auguring, flushing and other cleaning tasks) are provided, attempt to flush the system yourself by inserting a garden hose.
• You can resolve some groundwater problems with grading and drainage work, or control them with a sump (pit) pump. Evaluating the problem and designing a solution requires consultation with professionals.
• Plugging holes and filling cracks from the inside is rarely successful, especially if there's hydrostatic pressure on the wall.
• Interior dewatering that requires drilling holes in foundation walls and interior wall sealants at best get rid of dampness, not water.
• A 1,000-square-foot (93- square-m) roof will collect about 250 gallons (950 l) of water in a 2-inch (5-cm) rainfall. With four downspouts, that's about 63 gallons (240 l) to deal with at each location.
• You can resolve some groundwater problems with grading and drainage work, or control them with a sump (pit) pump. Evaluating the problem and designing a solution requires consultation with professionals.
• Plugging holes and filling cracks from the inside is rarely successful, especially if there's hydrostatic pressure on the wall.
• Interior dewatering that requires drilling holes in foundation walls and interior wall sealants at best get rid of dampness, not water.
• A 1,000-square-foot (93- square-m) roof will collect about 250 gallons (950 l) of water in a 2-inch (5-cm) rainfall. With four downspouts, that's about 63 gallons (240 l) to deal with at each location.