Design decision
Why this idea works
Designing the meeting of terrace and garden around where water goes turns runoff from a problem into a feature, guiding it along a planted route that slows and absorbs it. This green-infrastructure approach keeps the terrace dry and the garden watered, so the transition works with the rain rather than shedding it to a drain.
- The tradeoff
- The layout sets a clear direction, but it also commits the project to fixed relationships. Design where the water goes before the finish.
- How to measure it
- Conceptual range: the terrace plus a separately measured planted runoff route.
On your property
Plan it for your site
Keep the terrace sloped to feed the planted route cleanly, and detail the edge so water enters the planting without undercutting the slab. Size and plant the runoff route for the flow it carries, with species that handle wet and dry.
- Slope the terrace so runoff feeds the planted route cleanly.
- Detail the edge so water enters planting without undercutting the slab.
- Size and plant the route for real flow, with wet-and-dry-tolerant species.
Before forms are set
Build implications
- Confirm before estimating Terrace grading that feeds the planted route.
- Confirm before estimating A stable slab edge against the planting.
- Confirm before estimating A route sized and planted for real runoff.
- 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
- Calling a retaining element decorativeA wall or planter that holds soil or water needs support, reinforcement, drainage, and often professional review.
- Hiding runoff with plantingA rain garden, swale, or planted edge must receive water intentionally and have a safe overflow route.
- Choosing the finish before defining the jobSeat walls, planters, edging, terraces, and retaining walls may look related but carry very different loads and details.
Next step
Turn the idea into your estimate
Enter measurements from the property. The conceptual image does not provide a takeoff.
Estimate a similar concrete featureQuestions this idea raises
What is a drainage-aware transition?
A meeting of paving and garden designed around where water goes, guiding runoff into a planted route that slows and absorbs it. It is a green-infrastructure approach to the terrace edge.
Why route runoff into planting?
It slows and absorbs the water, easing drainage and watering the garden, instead of shedding it straight to a drain. Size and plant the route for the flow.
- Best when
- Drainage-aware features
- Reconsider when
- Reconsider the idea if retained soil or water, footing and reinforcement needs, drainage, and long-term access cannot be resolved on the property.
- Verify first
- Design where the water goes before the finish.
- Professional input
- Landscape or concrete contractor; engineer for retaining or structurally loaded work
Sources and further reading
- American Concrete InstituteTechnical context for seat walls, planters, and small structural concrete elements.
- EPA: Types of Green InfrastructureContext for rain gardens, planted swales, and water-aware transitions beside concrete.
- NRMCA CIP 6: Joints in Concrete Slabs on GradeA starting point for jointing terraces, landings, and larger flat features.
