Converting Raw Land into Saleable Lots and Desirable Communities Subdivision Design Converting Raw Land into Saleable Lots and Desirable Communities

Today’s Agenda What is a subdivision? Subdivision layout process Regulatory requirements Qualitative standards Subdivision layout process Design concepts Case study example

What is a subdivision? Conversion of a land parcel from its natural or previous state to: Legal entity, where lot ownership can be transferred Profit venture, where development costs can be recouped through lot sales Urban place, where neighborhood roots can be developed

Each Lot Must Have: Minimum size (sq. ft.) Minimum road frontage Provision for utilities Water/sewer or well/septic Electricity, phone, gas, cable, etc. Buildable area/feasible structure location Meeting setbacks, buffers Respecting constraints (slopes, soils, wetlands)

Subdivision Approval Process Sketch plan review Feedback on type (major/minor), regulatory fit Preliminary plat review Checks on roads, utilities, lots, etc. Final plat submission Install improvements or post bond Recorded in land and tax records

Sketch Plan

Preliminary Plat

Final Plat

What is a Good Subdivision Creates desirable social patterns Respects natural environment Provides efficient utility services Ensures accessibility (car, bike, pedestrian) Builds safe roads Minimizes cut and fill Seeks pleasant aesthetics

Elements of Success: 3 Scales Housing cluster or block Access, parking, yards Neighborhood Road systems Open space network Community Connectivity Activity centers

Building a Sense of Place Theme or big idea (e.g., walkable neighborhood) Amenity location (e.g., central park, pool) Unique landscape (e.g., native plants, oaks) Architectural style (e.g., neotraditional) Site graphics (e.g., entry sign, st. signs)

Central Commons as a Big Idea

Subdivision Layout Process Lot layout (rectangles, short side to st., build. area, n/s orientation, no double frontage) Open space, amenities Paths, sidewalks Utilities/storm water Vegetation & slopes Refine alternatives Regulations (density, lot size, open space, utilities, etc.) Average/minimum lot sizes Site analysis Road access Internal roads (topo, block layouts)

Open Space Subdiv. Design-1 Identify open space areas Primary conservation: wetlands, floodplains, steep slopes Secondary conservation: sensitive, scenic, unique uplands Locate house sites Maximum view lots, abut open space, min. lot width

Site Before Development

Traditional Yield Plan

Primary Conservation Areas

Secondary Conservation Areas

Open Space Subdiv. Design-2 Design road & trail alignments Level or rolling areas Avoid wetlands, habitats Minimize road length, cost, dead ends, long straight streets Draw in lot lines Use off center, up front houses for larger side & back yards

Adding Houses, Roads, Trail

Adding Lot Lines

Subdivision Street Concepts Curvilinear: naturalistic, organic Source: Frederick Law Olmsted Auto oriented street standards Examples: Treyburn, Gov. Club, The Oaks Neo-traditional: geometric, grids, diagonals Source: Andres Duany, Peter Calthorpe Pedestrian/transit/auto networks Examples: Seaside, Washington, South. Village

Subdivision Street Concepts-2 Urban cluster: geometric, central courts Source: Clarence Stein, Henry Wright Separation of auto service lanes & pedestrian paths and open spaces Example: Radburn, N.J.

Curvilinear, Grid, & Cluster

Basic Housing Layout Concepts Single family detached &/or attached Block: face street, w/ alleys (5-10 du/ac) Cluster: face st. or green, w/ alleys (4-6 du/ac) Parking court: face court (10-12 du/ac) Eyebrow: face island (3.5-6 du/ac) Multi-family Quadrangle: face court & parking (14-16 du ac) Parking court: face parking (15-18 du/ac)

Block Layout

Cluster Layout

Parking Court Layout

Eyebrow Layout

Multi-family Quadrangle

Multi-family Parking Court

Case study example Difficult hilly site 1st layout disregarded drainage ways, slopes 2nd layout left drainage ways open, followed natural contours with road

Case Study Site Analysis

Original Plan--Too Costly

Better Plan: Respects Contours