Design decision
Why this idea works
A sink at the greenhouse turns washing produce, rinsing pots, and cleaning tools into a one-stop job right where the work happens. The concrete pad handles the constant water and drips, and keeping the wash zone here means soil and mess stay in the garden instead of ending up in the kitchen.
- The tradeoff
- The layout sets a clear direction, but it also commits the project to fixed relationships. Plan the sink plumbing, drain, and outlet before the pour.
- How to measure it
- Conceptual range: the greenhouse pad plus a sink zone with plumbing and a drain.
On your property
Plan it for your site
A grippy, rinseable surface sloped to a drain suits a wet sink zone, and the plumbing needs planning before the pour. Detail the drain and its outlet so soil-laden wash water clears cleanly.
- Rough in the sink supply and drain before placing concrete.
- Slope the sink zone so soil-laden water clears to a suitable outlet.
- Confirm where garden wash water is allowed to drain under local rules.
Before forms are set
Build implications
- Confirm before estimating Sink plumbing and drain roughed in before the pour.
- Confirm before estimating A slope and outlet that clear muddy water.
- Confirm before estimating A wash-water disposal path that suits local rules.
- Measure the site and establish elevations Record boundaries, thresholds, grade changes, utilities, and the dimensions of vehicles, furniture, equipment, or structures that affect the layout.
- Test how the space will be used Check walking routes, turning paths, door swings, working clearances, maintenance access, and the route back to the house or street.
- Resolve drainage, services, and structural support Decide where water goes and coordinate drains, conduit, irrigation, fuel, electrical work, footings, and independent supports before forms are set.
- Define and estimate each concrete element Confirm the slab or footing section, base, joints, edges, and finish, then estimate simple measurable fields separately from steps, walls, drains, and supported features.
Prevent these problems
- Matching the wall footprint exactlyA small dry perimeter can improve the threshold, door clearance, maintenance access, and runoff control.
- Using one uniform thin sectionBearing walls, anchors, heavier storage, or manufacturer requirements may call for thickened edges or a footing.
- Allowing wet soil against the slabPoor grading, mulch, and irrigation can keep the pad edge damp and undermine the base or the structure above.
Next step
Turn the idea into your estimate
Enter measurements from the property. The conceptual image does not provide a takeoff.
Estimate a similar shed padQuestions this idea raises
Why have a sink at the greenhouse?
It lets you wash produce, pots, and tools where the work is, keeping soil and mess out of the house. A drained concrete pad handles the constant water.
Where does greenhouse wash water go?
It needs a drain and an outlet that suit local rules, since soil-laden water can silt up a poor detail or run afoul of drainage rules. Confirm the allowed disposal before building.
- Best when
- Greenhouse pads
- Reconsider when
- Reconsider the idea if base preparation, bearing edges, anchors, drainage, and building-manufacturer requirements cannot be resolved on the property.
- Verify first
- Plan the sink plumbing, drain, and outlet before the pour.
- Professional input
- Concrete contractor; verify the building manufacturer’s foundation requirements
Sources and further reading
- American Concrete InstituteTechnical references for small slab-on-grade pours and thickened edges.
- NRMCA CIP 6: Joints in Concrete Slabs on GradeUseful when a longer garden or greenhouse pad needs planned crack control.
- ICC model code portalCheck whether an accessory building or its slab needs a permit or setback in your area.
