Commercial Plumbing for New Construction
Commercial Plumbing for New Construction
Postma takes plumbing scope on new commercial construction across Chatham-Kent, Sarnia-Lambton and Windsor-Essex. Underground and below-slab through rough-in, top-out, fixtures and final inspection, working directly for general contractors, developers and building owners.
Plumbing is the trade with the least margin for error on schedule, because most of it goes in before the concrete is poured and the walls close. Underground that is wrong is expensive to correct and impossible to hide. We front-load the coordination for that reason.
Scope by Project Stage
| Stage | What We Handle |
|---|---|
| Preconstruction | Budget pricing from concept drawings, fixture and material takeoffs, coordination of water service and sanitary connection sizing with the municipality, and early flagging of anything with a long lead time or a permit dependency. |
| Underground | Below-slab sanitary and storm drainage, floor drains and trench drains, water service entry, sleeves and penetrations, grease interceptor and interceptor piping, and inspection before backfill and pour. |
| Rough-in | Drain, waste and vent stacks, domestic water distribution, gas piping to equipment, hydronic and mechanical room piping, hangers and supports, and coordination with structure, ductwork and electrical before anything closes in. |
| Top-out and testing | Pressure testing on domestic water and gas, hydrostatic testing on drainage, insulation, and sign-off with the inspector before walls and ceilings are closed. |
| Finish and trim | Fixture setting, trim and carriers, sensor faucets and flush valves, water heaters and recirculation, backflow preventers, mixing valves, and connections to kitchen and process equipment. |
| Closeout | Final inspection, backflow device testing and initial report filing, disinfection and flushing where required, as-built drawings, O&M manuals, warranty registration and owner training. |
One contract across three trades. We also self-perform commercial HVAC and commercial electrical, so plumbing, mechanical and electrical scope can sit on a single contract with one schedule and one set of coordination drawings. On a tight mechanical room or a congested ceiling, that removes the interface where most trade conflicts happen.
What We Install on New Commercial Builds
Drainage & VentingSanitary and storm systems, floor and trench drains, backwater valves, sumps and lift stations, roof drainage. |
Domestic WaterWater service, distribution, isolation valves, booster pumps, recirculation loops, backflow prevention. |
Gas & Process PipingNatural gas and propane distribution, equipment connections, compressed air, process and chemical feed lines. |
Fixtures & EquipmentCommercial fixtures and carriers, barrier-free groups, water heating, grease interceptors, kitchen connections. |
Decisions That Move Plumbing Cost on a New Build
These get decided early, often without much discussion, and they set the cost of the plumbing package more than anything that happens on site.
| Decision | What It Affects |
|---|---|
| Pipe material | Material choice on both domestic water and drainage changes install labour, expected service life and how the building sounds. Cast iron drainage costs more than plastic and is noticeably quieter, which matters in apartments, hotels and offices with occupied space below washrooms. |
| Water service sizing | Undersizing the service to save on the initial connection is one of the more expensive mistakes available, because correcting it later means going back into the ground and back to the municipality. We size for the building as designed plus any expansion you have told us about. |
| Water heating approach | Tank, tankless, or boiler-fed indirect. The right answer depends on peak demand rather than daily volume. A building with heavy simultaneous draw, such as a kitchen or a shower block, behaves differently from an office with washrooms only. |
| Backflow hazard level | The hazard classification of your building determines which devices are required and where. Boilers, irrigation, process equipment and fire lines each create their own requirement. Getting this settled at design avoids a device being added at inspection in the worst possible location for servicing it later. |
| Grease interceptor | Sizing follows kitchen output, and location decides what servicing costs for the life of the building. An interceptor placed for construction convenience rather than access turns every future pump-out into a bigger job. |
| Future expansion | If a phase two is planned, stubbing and sizing for it during the underground stage costs a fraction of opening a slab later. Tell us what the building is expected to become and we will build the capacity in now. |
Permits, Inspections and Closeout
Commercial plumbing carries more inspection points than most trades, and each one is a schedule dependency. We pull the permits, book the inspections and hold the work to the stage where the inspector needs to see it, which on a new build usually means underground before backfill, rough-in before close-in, and final at occupancy.
- Plumbing permits and municipal inspections at each required stage
- Pressure and hydrostatic testing with documented results
- Gas piping installed and pressure tested by G1 and G2 licensed technicians
- Backflow device installation, initial certified testing and report filing under the local cross-connection control program
- Disinfection and flushing of new potable water systems where required
- As-built drawings, O&M manuals, warranty registration and owner training at handover
Commercial Plumbing New Construction FAQ
Do you work directly for general contractors?
Yes. Most of our new construction plumbing is scope under a general contractor. We also work directly for developers and owners on design-build, and we bid plan-and-spec tendered work for institutional and municipal projects.
Can you take plumbing, HVAC and electrical on one contract?
Yes, and it is usually why contractors call us. One contract, one schedule, one set of coordination drawings and one point of accountability at closeout instead of managing the interface between three separate subcontractors.
Are you licensed and insured for commercial construction in Ontario?
Yes. Licensed plumbing contractor, TSSA registered, ECRA/ESA licensed electrical contractor, G1 and G2 gas technicians and certified backflow testers on staff, WSIB in good standing and full liability coverage. Certificates are available for prequalification packages.
How early should we bring you in?
As early as there is a floor plan and a use for the building. Water service sizing, drainage routing, interceptor location and backflow requirements are all cheap to get right at design and expensive to change once the underground is in.
Do you handle tenant fit-outs and renovations in occupied buildings?
Yes. Fit-outs, washroom renovations and phased work in occupied space are routine, including off-hours scheduling and temporary shutdown planning so tenants keep water service through construction.
Who handles service after the building is turned over?
We do. Our commercial service department carries the warranty on what we install and can put the building on a maintenance agreement from day one, which covers annual backflow testing and keeps you compliant from the first year. See commercial plumbing maintenance.
Do you install process and industrial piping on new plants?
Yes. Process water, chemical feed, compressed air, glycol and equipment connections, including piping modifications and tie-ins scheduled around production or a planned shutdown.
See all commercial plumbing services, or our commercial HVAC new construction for the mechanical side of the same project.
Have a project to price? Send us drawings, or just a building type and square footage, and our commercial team will scope the plumbing package. Postma provides plumbing, HVAC and electrical on a single contract across Chatham-Kent, Sarnia-Lambton and Windsor-Essex. Call 519-354-9491.