Nobody notices their perimeter drainage failing. They notice the damp patch, and by then the water has been in the wall for weeks.
How it fails
Perimeter drainage — drain tile — is a perforated pipe in gravel around the footing, carrying groundwater away from the foundation. It fails three ways, and all of them are gradual.
Silt washes in through the perforations and settles, narrowing the pipe until it carries nothing. Roots find the perforations and fill the pipe. Collapse or settlement creates a low spot that holds water permanently.
Older Lower Mainland homes often still have clay tile or early perforated pipe, and on the slopes above Marine Drive in North Vancouver the volume of water moving downhill is far higher than most homeowners realise.
The signs
- Damp or efflorescence — white powder — at the base of a basement wall
- A musty smell that returns every autumn and goes in spring
- Water pooling against the foundation outside after rain
- Downpipes discharging at the base of the wall rather than into a drain
- A sump that runs far more than it used to
Flushing versus replacing
Not every system needs replacing. A camera inspection tells you whether the pipe is intact and simply silted, in which case flushing restores it, or whether it has collapsed, in which case it has not. Flushing is a fraction of the cost of excavation, and it is worth establishing which situation you are in before anyone quotes you for digging.
What it costs you to wait
Water against a foundation does not stay outside it. Once it is in the wall you are looking at remediation and finishes on top of the drainage work, and in a finished basement that multiplies the cost several times over.
Booking it
We work across Langley, Surrey, Vancouver, Burnaby, Richmond, the North Shore, the Tri-Cities and the Fraser Valley. Licensed and insured, with a written workmanship warranty set out in our Service Guarantee.
This is one of eight jobs we cover in the autumn plumbing guide for the Lower Mainland.
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- Pipe Insulation and Heat Trace: Where Pipes Actually Freeze
