Water and moisture control

• Drain Tile
  We installed drain tile and a sump pit all around the perimeter of the basement. This is essentially a perforated plastic pipe wrapped in cloth. The pipe is then covered in coarse river gravel to allow water to drain into the pipe. The whole pipe is angled towards the sump pit, where any water that accumulates is pumped out. The walls of our basement are cinder block, which is known to "weep." To prevent this, once the drain tile was installed, holes were punched in the bottom of the wall to allow any water in the wall to drain into the drain tile.

  After the basement was dug out, 8 inches of crushed gravel were added back to allow water to move to the drain tile. This prevents hydrostatic pressure under the slab, which can cause water to come up through any small cracks in the new slab. U.S. Waterproofing is the company that actually installed the drain tile and sump pit.

• Backup Pump
  The sump pit uses an electric pump to remove any groundwater that enters the sump pit from the drain tile. If the power goes out, which is of course more likely during a storm when it is raining, you are at risk of having your basement flood. Most people use a battery powered backup pump that takes over if the regular pump has no power or fails. The problem with this approach is that even if you use a deep cycle battery, it will only protect you for several hours, the battery needs to be replaced at least every 5 years, and while not common, lead-acid batteries can explode. We opted for a venturi pump which is driven off of the municipal water supply. Water pressure from the city water mains is used to remove water from the sump pit when the main pump fails. The pump we used is the Basepump. The only caveats about using a water driven pump is that, at least for the model we chose, you need a minimum of 50 psi to provide enough lifting power. Also, these kinds of pumps will use water to remove water, so you will be discharging extra water into your yard over and above what is removed from the sump pit.
• Plastic Barrier under Slab
  Before the new slab was poured, heavy weight polyethylene sheets were laid on top of the crushed gravel to help create a moisture barrier below the concrete.
• Delta FL underlayment
  Once the slab was poured, we used a material called Delta FL on top of the slab as an underlayment below the plywood subfloor. It is essentially a dimpled plastic sheet that creates a small airspace just above the slab. This allows any moisture that comes through the slab to evaporate. The airspace also has insulating value which helps keep the floor warmer.
• Overhead Sewer
  We installed an overhead sewer. It works by having all the drains in the basement drain to an ejector pit where it is then pumped up above grade and then drains back down into the sewer. This makes sewer water backing up from the street into your house essentially impossible. Drains other than basement drains still drain by gravity directly into the sewer; they don't drain to the ejector pit. The City of Lombard has a great diagram that explains it very well.

• Humitek
  Even though we went to great lengths to make sure the basement stayed dry, we used moisture and mold resistant drywall for the walls, USG Humitek.
• Washing Machine Shutoff Valves
  Finally, since washing machines can occasionally run over, and this would be a small disaster with our wood floor, we installed a device called Floodstop. It consists of two shutoff valves, a floor sensor, and a control module. If the washing machine overflows, the sensor gets wet, and the valves shut off the water to the washing machine and an alarm sounds.