Exterior Membrane Waterproofing · Waterloo
Exterior Membrane Waterproofing in Waterloo
Exterior waterproofing is the most complete fix in this trade and the most disruptive. It is the right answer for some Waterloo houses and the wrong answer for others, and the difference is the lot, the wall and the water.
Every basement wall in Waterloo built in the last several decades went into the ground with some kind of coating on the outside and a run of weeping tile at the footing. The coating on most 1970s-90s houses in Beechwood, Lakeshore and Lincoln Village was a sprayed or brushed tar-based dampproofing, which was never meant to hold back standing water and has now been in the ground for thirty to fifty years. The weeping tile was often clay or early perforated plastic, and on the clay pockets of the Moraine it silts up. Exterior waterproofing replaces both with something built for water that sits against the wall rather than drains past it.
What the job involves
- Locates and access. Gas, hydro, water and communications lines are located before a shovel goes in. Decks, steps, air conditioners, gardens and fences along the wall come out or get protected. On a tight Waterloo lot with a neighbour's driveway a metre away, access decides whether this job is possible at all.
- Excavation to the footing. The trench runs the full height of the wall down to the top of the footing, shored where the depth and soil require it. In Moraine sand the trench walls slough and need to be cut back wider; in clay they stand up but the spoil is heavy and wet.
- Wall preparation. The old coating and soil are cleaned off, cracks are repaired, honeycombed concrete is patched, and the joint between wall and footing is filled with a cove.
- Membrane. A waterproofing membrane goes on the whole wall from the footing to grade. It may be a rubberised liquid-applied membrane or a self-adhering sheet, and the choice depends on the wall surface, the temperature and the soil.
- Drainage board. A dimpled drainage board over the membrane keeps soil off it and gives water a free path down the wall to the tile.
- New weeping tile. Perforated pipe in a bed of clear stone, wrapped in filter fabric, laid beside the footing with fall toward the sump or the storm connection.
- Backfill and grade. Clear stone over the tile, then backfill, compacted in lifts, and the grade finished sloping away from the house. Where the original backfill was clay, some of it is replaced with material that drains.
Where it is the right call in Waterloo
Exterior work makes sense when the wall itself needs to be dry, not just the basement. That includes a wall where the exterior coating has failed across a whole face, a block wall with water in the cores, a wall where a finished basement, a bedroom or expensive built-ins sit against it and the owner wants no water inside the wall at all, and a house on one of the Moraine's clay pockets where the backfill holds water like a bathtub. It also makes sense when the outside is already being torn up for a deck, a driveway or an addition and the extra cost of doing the wall while the trench is open is small.
Where it is the wrong call
On a lot where the water comes up through the floor rather than through the wall, which is the pattern on low ground near Laurel Creek and in parts of Lakeshore, exterior work on the wall does not touch the problem. On an uptown lot where the house sits a metre from the neighbour's and the porch, the walkway and a hundred-year-old tree are all in the way, the digging costs more than the result is worth and an interior system does the job. And on a single leaking crack in a poured wall, excavation is a large answer to a small question. We will say which one you have.
Permits, the floodplain and the Moraine
Exterior excavation changes grading and drainage on the lot, and the City of Waterloo is where lot grading and any permit questions start. If the property is near Laurel Creek or the Grand, it may be in an area regulated by the Grand River Conservation Authority, and exterior work there may need their approval first. Both get checked during the quote. Where the weeping tile discharges — to a sump, to the storm sewer where the city allows it, or to grade — is settled before anything is dug, not improvised on the day.
What you should expect to be disrupted
Honestly, a lot. The side of the house is a trench for the length of the job, the lawn and gardens along it are gone and get reinstated, and an excavator and a stone truck need to get to the wall. On most Waterloo lots that means one or two walls at a time, and on a corner lot or a house with a wide side yard it can mean the whole perimeter. The written scope says exactly what will be removed, what will be reinstated and what will not, so there are no surprises about the rose bed.
Frequently asked questions
Is exterior waterproofing better than interior?
It is more complete, because it keeps water out of the wall rather than catching it after it comes through. It is also far more disruptive and costs more. It is the right answer for a failed exterior coating, a block wall taking on water, or a wall with finished space that must stay dry. It is the wrong answer for water rising through the floor on a high water table lot, or where there is no room to dig.
Can you dig on a tight uptown Waterloo lot?
Sometimes. Older lots uptown and in Mary-Allen often have the neighbour's house, a porch, a walkway or a mature tree within a metre or two of the wall, and hand digging or shoring changes the job. Where it cannot be done sensibly, an interior drainage system is usually the better answer, and we will say so.
Do I need a permit for exterior waterproofing?
It depends on what changes. Work that alters grading, drainage or discharges to the storm sewer involves the City of Waterloo, and lots in the Grand River Conservation Authority's regulated area near Laurel Creek or the Grand may need conservation authority approval. That is confirmed for your address during the quote.
Serving Waterloo and surrounding areas. Contact us for a no-obligation quote specific to your property.