A relatively inexpensive and highly effective basement waterproofing method, compared to external excavation and waterproofing, is an internal de-watering system. This type of waterpoofing system is also referred to as a perimeter drain system, an interior perimeter basement waterproofing system, an internal weeping tile system, and an internal breakout. This basement waterproofing method is used mainly in concrete block foundation waterproofing applications. The drain system keeps a basement dry by providing drainage for water that pools within concrete block / cinder block foundation walls, as well as for any water that leaks through foundation cracks. This basement waterproofing system effectively replicates the weeping tile system that is installed along the footing on the exterior of the foundation and will keep your basement perfectly dry.

This method of basement waterproofing involves the installation of a perimeter drainage system on the inside of the basement, beneath the basement floor; therefore, no digging outside the home is required. Concrete block / cinder block foundation de-watering allows a block foundation, into which water has pooled, to drain; thus preventing water from leaking from the concrete blocks onto, or under, the basement floor. By draining the cinderblocks, the system helps to extend the useful life of the concrete blocks which deteriorate over time due to the saturation of the blocks by pooled water within them. Properly installed, an internal de-watering system will keep your basement dry for the life of your home.

Installation of a Perimeter Drain / Internal De-watering System

Installation of this perimeter drain system requires access to bare basement walls inside the home.

1. The basement floor slab, next to the foundation walls is jackhammered open in order to expose the footing and create a trench for the subsequent installation of drain pipe;

2. The fully exposed bottom course of concrete blocks have weeping holes drilled into the hollow cavities within the blocks;

3. A perforated drain pipe is installed next to the footing;

4. An air gap membrane is installed along the wall to grade, or higher;

5. In the absence of a suitable sump pump, a sump liner and submersible pump are installed beneath the floor, with the liner cover flush with the floor;

6. The drain pipe is routed to the sump liner, beneath the basement floor, so that the water collected from the draining blocks can be mechanically evacuated to the exterior by the sump pump. Note: it is illegal in most municipalities in the GTA to dispose of this water by using the floor drain; and

7. The drain pipe and lower portion of the membrane positioned and concrete is poured over top and levelled. On completion, all you will see is a scar in the floor along the wall, a membrane fastened to the wall, and a sump pump discharge pipe to the exterior.

How water enters and pools within a concrete block foundation:

The steps involved in performing internal de-watering:

Below is a typical sump pump installation that is part of the internal de-watering system.

Note: Instead of having an unsightly discharge pipe emerging from the centre of the sump liner, it is possible to conceal the discharge pipe within the framed basement walls by modifying the configuration of the discharge so that it is "discrete" (beneath the concrete floor and travelling up the wall behind the drywall).

For a healthy and dry basement, and a truly professional perimeter drain system installation Contact us.