Why drains depend on slope
Drains work by gravity. Pipes need a consistent fall toward the sewer, and that slope has to fit within the floor and ceiling heights. In renovations, this can be the hardest constraint. A washroom far from the main drain may need a pump or trenching in the slab.
We survey existing elevations before planning, so promises about layout are based on real numbers.
What a system includes
- Underground drains below the slab
- Stacks and horizontal branches above
- Floor drains, trap primers and cleanouts
- Vent piping through the roof
- Sumps and ejector pumps where gravity will not work
- Storm drain connections, coordinated with roofing
- Fire stopping where pipes pass through rated assemblies
Venting
Vents equalize air pressure so water flows freely and traps keep their seals. They also carry sewer gas to the roof. A building with poor venting gurgles, drains slowly and smells.
Vent terminations on the roof need to be clear of air intakes and properly flashed. In Alberta, they can frost over in extreme cold, and larger pipes at the roof help prevent that.
Testing and inspection
Drain systems are tested before concealment, often with water or air. Inspectors check slope, support and venting. We schedule them so walls and slabs are not closed too early.
Below-slab work is the point of no return. We confirm every location with other trades and the architect before concrete is poured. Our carpenters, concrete partners and plumbers keep a shared set of marked drawings.
Existing drains deserve a look in renovations. Camera inspection can show cracks, roots or blockages. We tell you what we find and recommend repair or replacement. Planning for cleanouts at accessible locations saves money for years, since a clogged line with no access means opening floors.