Drainscope - perimeter drainage systems:

Perimeter Drainage Systems

In Victoria, BC, the greatest natural threat to the safety of our possessions is winter rainfall and the flooding it brings. The principal weapon to combat such problems is your home's perimeter drainage system (sometimes called footing drains). Unfortunately, most houses built locally prior to the mid-1980's have antiquated clay or concrete tile systems, or, in the case of older homes, sometimes no drainage at all.

Clay and concrete tile systems are composed of 30cm (1') long sections of solid 4" diameter vitreous clay or concrete pipe laid end-to-end with small gaps between them to allow for water entry. Over time, however, tree and shrub roots in search of water push their way under, between and straight through the tiles, eventually forcing them out of line or simply breaking them. This creates two primary problems:

Increased gaps allow for the intrusion of surrounding soil, which clogs the tiles and further encourages root growth within
With the tiles pushed out of line, there is no longer a consistent, downhill grade to direct water away

This problem is compounded by the fact that concrete tile lacks the reinforcement of structural concrete (i.e. foundation or sidewalk) and has an inherent tendency to dissolve over time in wet ground.

Modern drainage systems consist of continuous PVC or ABS plastic pipe bedded in a layer of round drain rock. A complete drainage system includes two separate runs of pipe:

4" perforated pipe (footing drain) at the base of the foundation dedicated to picking up the ground water which threatens to seep through the foundation
3" or 4" solid pipe (tight pipe) (rainwater lead) sitting above the perforated pipe to take away roof water being channeled into the system by way of the gutters and downspouts

The two-pipe system ensures that extra rain water from the roof is not being sent into pipes which are already working hard to take water away from the foundation.

The two pipes combine past the low point of the foundation into a solid pipe traveling off the property into the city's storm drain mains.

If the city's storm drain mains is sitting at a higher elevation than the low point of the perimeter drainage system (an all too common scenario in many areas of town), a sump pump will need to be installed.

It is possible (although it can sometimes create grade challenges later on) to replace clay or concrete tile systems one section at a time. Flexible couplings are available to connect new plastic pipe to the old tile. Although the final cost of replacing the entire system will be higher, the financial burden can in this way be spread out over several years.

Homeowners whose drains are not working satisfactorily will often attempt to bypass the problem by directing their downspouts away from the house. It is important to remember that this water has to end up somewhere. It will either find its way back through the soil to the foundation, create washouts in the yard, or simply transfer the problem to your unsuspecting neighbors.

Remember: In the city, it is NEVER an appropriate solution to simply direct unwanted water out to the property line. This is how law suits happen.

Don't wait until its's too late! Call DrainScope to Inspect & Clean your Perimeter & Sewer systems Today.

 

Call Today 250.590.1535

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