RESTROOM CONSTRUCTION
Commercial restroom build-out plumbing
TWO CODES AT ONCE
A restroom has to satisfy the plumbing code and the accessibility standard
The plumbing code sets how many fixtures the space needs, how they drain and how they vent. The accessibility standard sets where those fixtures sit, how much clear floor space is around them, how high they are mounted and what the reach ranges are. A restroom can be plumbed perfectly and still fail because a grab bar is an inch out of position.
Fixture counts come from the occupant load, which comes from the use and the square footage. A tenant improvement that changes the use or increases occupancy can push the building into needing more fixtures than it has — which is an expensive discovery if it happens after the layout is approved.
Alterations bring their own rule: when you alter a restroom, the altered elements generally have to comply with current standards, even if the rest of the building is grandfathered. Many jurisdictions also require accessibility improvements along the path of travel once the project cost passes a threshold.
What we check before layout
- Occupant load and required fixture count for the use
- Existing fixture count and whether it is still compliant
- Clear floor space and turning radius in the proposed plan
- Mounting heights measured to finished floor and wall
- Grab bar backing and blocking in the framing
- Path of travel from the suite entry to the restroom
RESTROOM SCOPE
What goes into a restroom build-out
Fixture count verification
Occupant load calculated from the use and area, then checked against the plumbing code’s required water closet, lavatory and drinking fountain counts before the plan is finalized.
Accessible layout
Clear floor space, approach and turning dimensions, door swing and reach ranges verified on the drawing so the inspector finds nothing to write up.
Carriers and fixture setting
Wall-hung carriers set plumb and at the correct height, floor-mounted fixtures anchored properly, and all mounting measured to finished surfaces.
Drainage and venting
Branch waste sized for the fixture units, vents run to satisfy the code’s distance and sizing rules, and cleanouts placed where they stay accessible.
Tempered water
Mixing valves and tempering for lavatories, set and documented so the delivered temperature is within the range the code requires.
Janitor and support fixtures
Mop basins, hose bibbs, floor drains and the drainage that keeps a janitor closet usable, plus drinking fountains and bottle fillers where required.
BUILD SEQUENCE
How restroom work is sequenced
01
Verify the count before the plan is fixed
02
Dimension the accessible fixtures
03
Underground or in-slab drainage
04
Rough-in with blocking coordinated
05
Fixture setting and trim
06
Final inspection
COMMON QUESTIONS
Restroom build-out questions
It depends on the occupant load, which is calculated from the use and the floor area, and on which plumbing code your jurisdiction has adopted. We run the calculation during pricing and tell you whether the existing restrooms already satisfy it.
No, but the elements you alter generally do have to comply with current accessibility standards. Separately, many jurisdictions require a portion of the project budget to be spent on the path of travel — entrance, route, restrooms, drinking fountains — when alterations exceed a cost threshold.
Because the blocking was set before the final fixture selection, or the height was measured to the substrate rather than the finished wall. We confirm blocking locations with the framer at rough-in and verify against the actual specified fixture.
Usually yes, provided the wall can take a carrier and there is depth for the chase. Wall-hung water closets make floor cleaning easier and are common in commercial restrooms, but they need more wall depth than a floor-mounted fixture, which has to be allowed for in the partition layout.
In many occupancies, yes, and the requirement is usually for fixtures at two heights. Some jurisdictions accept a bottle filler in place of one unit. We check the local amendment rather than assuming the model code applies unchanged.