Exterior Excavations are required to install, repair or replace drain tile located at the perimeter footing. It is not uncommon for drain tile to become blocked by dirt and tree roots over time or suffer from a collapsed section preventing proper drainage. In fact, this is one of the most common causes of basement flooding. To learn more about drain tile, see our section on Weeping Tile. In some cases, the tile may have been incorrectly installed or have shifted over time.
Where an existing drain tile does not enter the house into a sump pit, it will either be connected in the country to a field tile or municipal drain. In the city it will be connected to the sanitary or storm sewer. In exceptionally rare cases, it does not lead anywhere. Often it will be recommended that we dig a test hole down to the drain tile in order to attempt to utilize a camera to assess the problem area recommend the appropriate remedy.
In homes built pre-1970, the drain tile was actually hooked up to the sanitary sewer in many cases. This is a hazardous situation which can lead to extensive and costly damages should the sanitary sewer ever backup from the street drain. Some cities, such as London and Stratford, have subsidy programs to help the homeowner remedy this situation. See our Basement Isolation section for more information.
When access to the foundation walls from the inside is limited or just not practical, an Exterior Excavation may be your best choice for waterproofing your basement walls and permanently preventing water from entering your home through the foundation walls. Not all leaks enter through the walls though and while an Exterior Excavation will address water that may enter between the floor/wall/footing joint, it may not address a hydrostatic pressure situation without doing additional work from the inside. Your DryBasements.com Estimator will provide you full details and explain alternative options such as an internal breakout.
An excavation is made to the footing along the problem area
A new drain tile is installed
The Air-Gap membrane is installed from grade level, down to the footing, and over the tile
The top and sides of the membrane are sealed to prevent entry of water and silt
6 to 8 inches of drainage stone is placed over the tile prior to backfilling with native soil
Filter fabric is then installed over the drainage stone to prevent silt from entering your new tile
Excess soil is left above the trench to allow for settling
Learn more about exterior excavation and whether or not it’s right for your needs. Talk to DryBasements.com today.