Exterior Waterproofing Services

Waterproofing the exterior of your home, is the most effective way to stop water from penetrating your foundation wall. The idea of external water proofing is to seal the water leak, rather than redirecting where water ends up. The installation of a waterproof membrane along the outside of the foundation wall, has the ability to stop further erosion and degradation of your home’s foundation. During the water proofing process the existing weeping tile drainage system is upgraded, allowing for external transport of surrounding water, keeping your basement dry. The external waterproofing system is a multi-step process that is outlined below.

External Waterproofing Procedure

1. Excavate area around foundation wall.

Excavation is typically done with an excavator, making a 20”-30” trench around the perimeter of the house or target area. All excavation is done with compliance to Technical Standards and Safety Act, outlining proper procedures during excavation around utilities and underground dangers.

Alternative methods of excavation include hand digging and hydro-excavation, which are both suitable methods to expose underground utilities, and allow for excavation in areas inaccessible by means of an excavator.

Excavation depth can vary on each house, as the depth of foundation footing from the surface ground level may vary between situations. Excavating to the bottom of footing is very important when waterproofing, as the new weeping tile must be laid at the same level as the bottom of the footing.

2. Remove existing weeping tile.

Weeping tile material can very on each house, the determining factor is when the weeping tile was installed. Older houses dating back to pre-weeping tile technology, and have no active method of draining ground water, in this case a full drainage system is required.

The first generation of weeping tiles installed are clay weeping tiles. These tiles are 1’ to 2’ in length and are laid from end to end with no mechanical means of connection.

The last type of weeping tile that can be found in Ontario, is corrugated/perforated weeping tile which has more recently been upgraded to be encapsulated in a filter sock.

In all cases the weeping tile is removed as previous experience as shown the commonalities in plugged or damaged weeping tile due to improper installation, tree root growth inside the weeping tile, and sediment accumulation stopping water flow.

3. Apply waterproof membrane to wall.

The application of water proof membrane can vary between contractors, however the Pro WaterProofers method an up to date, modern method which is currently specified by structural engineers. The application of waterproofing membrane may be based on the foundation wall construction, as some instances will require a self-adhesive membrane, where other instances require a sprayed on monolithic coating. Each project is matched with the best suited waterproof membrane for the best quality results.

4. Install drainage board.

Drainage board is the dimpled board that most people are familiar with, as it tends to stick up above grade. Although drainage board isn’t a primary waterproof membrane, it made to span from the grade level to the weeping tile level at the footing of your foundation wall. All drainage boards are intended to be installed over liquid or sheet water proofing membranes, assisting in directing water downwards to the weeping tile, helping keep your foundation wall dry.

5. Install new weeping tile drainage system.

In all cases a new corrugated/perforated weeping tile within a filter sock is always installed. In many cases when water proofing is required, the existing weeping tile does functioning as well as a new one would, so the existing weeping tile is always replaced.

6. Lay ¾ inch clear stone to act as a filter and allow water migration to weeping tile.

Laying a proper amount of ¾” stone is just as important as a new weeping tile. The tile works in conjunction with the stone around it to help surrounding ground water migrate through the stone into the tile, keeping the foundation dry. Clear stone, sometimes referred to as drainage stone, surrounds the weeping tile, allowing for clean water to passes through the filter sock of the weeping tile.

7. Install 1 inch foam to act as insulating factor and protect waterproofing layers.

When waterproofing basement foundations, it is common to backfill with the existing soil that was is surrounding the house. Over the years it has been found that previous waterproofing membranes have failed because of being damaged during the backfill process. The use of foam on the exterior of the drainage board acts as a cushion, preventing the tendency of tears and lacerations, caused by the backfill containing debris, pulling on the drainage board.

8. Backfill trench with native soil.

Under normal circumstances the trench is backfilled with the native soil excavated at the beginning of the job. Many circumstances call for the native soil to be removed from site and stone used to backfill the trench to avoid any type of settling, minimizing horizontal pressures and improved drainage. The removal of native soil is almost always recommended when working around areas that require concrete or pavement. The use of a high performing backfill is beneficial in eliminating future settling and sinking.