Wet Basement Drainage

Keeping Your Home's Feet Dry

Table of Contents

Part I: Drying Out Existing Basements

• 1.0 Determining the problem, how water can get in: Troubleshooting Guide
  • 1.1 Plumbing leaks
  • 1.2 Surface water entrances: how water finds its way in
  • 1.3 Groundwater, the rising tide: how a basement is like a well
    • 1.3.1 High water table, where does it come from
    • 1.3.2 Springs and things
    • 1.3.3 Looking for the signs of trouble in nearby wetlands, road cuts and hillsides
    • 1.3.4.Checking nearby dug wells & septic systems
  • 1.4 Condensation/high humidity
    • 1.4.1 Moisture holding capability of water
    • 1.4.2 Thermal mass of concrete and stone
• 2.0 Back to Basics: Understanding the interaction of soil and water
  • 2.1 Difference between sand, silt & clay
  • 2.2 Effect of hardpan and ledge on water movement in the ground
  • 2.3 Relation of water table to the ground surface
  • 2.4 Capillary action
• 3.0 Choosing and executing a solution
  • 3.1 Dealing with surface water leakage (only if you’ve ruled out groundwater as a problem)
    • 3.1.1 Cut stone, field stone & rubble foundations;
    • 3.1.2 Block foundations: block failure, poor mortar, buckling, settling
    • 3.1.3 Poured foundation: Settling cracks, honeycombing, pour joints, tie leaks;
    • 3.1.4 Utility penetrations
    • 3.1.5 Windows, window wells;
    • 3.1.6 Other unique problems
    • 3.1.7 Surface grading errors
    • 3.1.8 Gutters, downspouts and the North Country
  • 3.2 Creating a dry island - using perimeter drains
    • 3.2.1 Locating and restoring a “lost” drainpipe
    • 3.2.2 Location and depth for retrofit installation
    • 3.2.3 Bedding material: concrete sand vs. stone
    • 3.2.4 Pipe choices
    • 3.2.5 Adding insulation to the wall when the hole is open
    • 3.2.6 Commercial drainage products: Mirafi. Dow Corning, etc
    • 3.2.7 Interior drains: When to choose this alternative, why do most commercial outfits do it
      • How to do it
      • Double duty for drainage and for radon mitigation
    • 3.2.8 Combining interior and exterior in extreme conditions
    • 3.2.9 Backfilling and backfill material:
  • 3.3 Getting rid of the water, some rules to follow
    • 3.3.1 Gravity drain to outlet
      • choosing pipe;
      • outlets & rodent guards
    • 3.3.2 Sump pump systems
      • sumps & pumps
      • discharge lines, frost protection
    • 3.3.3 Relocating water underground: drywells & soakaways
    • 3.3.4 Obtaining necessary permits and/or permission to discharge
• 4.0 Dealing with condensation
  • 4.1 Ventilation vs. dehumidification
  • 4.2 Vapor barriers

Part II : Protecting a New Foundation or Addition From Water

• 1.0 Siting the house for success,
  • 1.1 Determining if there is likely to be a high water table
    • 1.1.1 Check locally, ask the neighbors, look in a well
    • 1.1.2 NRCS, your tax money at work
    • 1.1.3 Check or get a septic plan etc
  • 1.2 Choosing whether gravity vent possible or sump pump required
    • 1.2.1 Can building be raised enough to gravity drain.
      • Modification of house design to daylight basement
      • Cost of fill to raise structure vs. long term cost of pumping
      • Option to not have basement because of extremely high water table
    • 1.2.2 Regulations for setback & separation distances
    • 1.2.3 Permission from beneficiary of water if necessary
  • 1.3 Placing drains inside footing, outside, or both [see Part I, 3.1.3 above]
  • 1.4 Establishing elevations for footing drain and outlet; “the tail wagging the dog”
• 2.0 Executing the drainage system
  • 2.1 Follow recommendations in PART I, 3.2 & 3.3 above
  • 2.2 Protecting drainage system during construction if not backfilled immediately
• 3.0 Waterproofing the walls
  • 3.1 To paint or not to paint with tar
  • 3.2 Treating all defects and penetrations; see PART I, 3.3 Exterior wall insulation: See PART I, 3.2.7
  • 3.4 Commercial dampproofing/waterproofing products: see PART I, 3.2.8
  • 3.5 Window, window wells: see PART I, 3.1.2
• 4.0 Backfill & finish grade: see PART I, 3.1.4, 3.1.5
• 5.0 Other considerations
• 6.0 Glossary