Sites on the edge of urban forest preserves present unique opportunities for residential architecture. The Hoke Residence, situated at the boundary of Portland’s Forest Park, demonstrates how nature-integrated architecture can respond to both a challenging sloping lot and the desire for dramatic interior spaces. At 4,800 square feet, the home uses finished concrete and glass walls to frame the surrounding trees rather than compete with them. The result is a residence that reads as part of its landscape while delivering generous, flowing spaces on a relatively small building footprint.
Designing for Sloping Urban Sites
A sloping site presents both constraints and opportunities. The grade change across the building footprint determines how the structure engages with the ground and what kind of walkout spaces are possible on lower levels. In the case of this hillside residence, the slope allowed the architects to create a sunken living room and a study passive house design advantages while maintaining visual connection to the outdoors through full-height glass walls.
Foundation Strategies for Sloped Lots
| Foundation Type | Best For | Typical Cost Premium vs. Flat Site |
|---|---|---|
| Step-down foundation | Moderate slopes (5-15%) | 10-20% |
| Pile and grade beam | Steep slopes (15-30%) | 25-40% |
| Drilled pier with elevated slab | Very steep slopes (30%+) | 40-60% |
| Stem wall with retaining notch | Variable slopes with walkout basement | 15-30% |
For the Hoke Residence on the edge of Forest Park, the foundation solution had to minimize disturbance to existing tree root systems while providing adequate bearing capacity. A combination of drilled piers and a grade beam system accomplished this goal. The piers extended to competent bearing strata below the organic topsoil, while the grade beam distributed loads horizontally between pier locations. This approach preserved mature trees close to the building envelope, maintaining the forested character of the site.
Early Geotechnical Investigation
Hillside projects benefit from geotechnical investigation before schematic design begins. Soil borings drilled to depths of 10 to 30 feet reveal the bearing capacity, groundwater conditions, and potential for soil movement that inform foundation selection. For this site, the geotechnical report confirmed stable volcanic subsoils typical of the Portland area, with allowable bearing capacities sufficient for a conventional pier foundation without deep underpinning.
Material Selection: Concrete Walls and Glass Panels
The exterior material palette of this modern hillside home is intentionally restrained. Finished concrete and glass compose the primary surfaces, with wood framing the glass panels to add warmth at the human scale. This material strategy serves multiple purposes: concrete provides thermal mass that moderates indoor temperature swings, glass maximizes views of the surrounding forest, and the wood detailing softens what could otherwise feel like an industrial aesthetic.
Concrete Wall Construction for Residential Use
Finished concrete walls in residential construction require careful planning during the pour and curing stages. Unlike concrete that will be covered with cladding or drywall, exposed concrete must meet aesthetic standards for surface uniformity, color consistency, and defect tolerance.
- Formwork selection: Plywood forms with a smooth, defect-free surface produce the cleanest finish. Medium-density overlay (MDO) plywood is the standard choice for architectural concrete.
- Release agent: A chemical release agent applied to the form faces prevents the concrete from bonding to the plywood during stripping. Water-based agents are preferred for environmental compliance.
- Mix design: A low water-cement ratio of 0.40 to 0.45 with superplasticizer additives maintains workability while achieving the 4,000 to 5,000 psi compressive strength typical for residential foundation and wall applications.
- Vibration: Internal vibrators consolidate the concrete within the formwork, eliminating honeycombing and air pockets near the visible surface. Over-vibration must be avoided as it causes aggregate segregation.
- Curing: Wet curing for a minimum of 7 days prevents surface cracking from rapid moisture loss. Curing compound or continuous water misting maintains surface hydration during this period.
Glass Wall Performance Specifications
Full-height glass walls in the living areas require high-performance glazing to meet energy code requirements. The glass wall assemblies in this residence use triple-glazed units with low-E coatings and argon gas fill, achieving a U-value of approximately 0.20 BTU/hr-sq ft-°F. The wooden frames, while visually prominent, incorporate thermal breaks to prevent condensation and heat loss at the glass edge. Structural silicone glazing eliminates visible stop profiles on the exterior, creating the uninterrupted glass surface that defines the modern aesthetic.
Indoor-Outdoor Flow Through Strategic Deck and Patio Systems
The Hoke Residence features an extensive system of decks and patios connected to interior spaces by door-to-ceiling openings. These outdoor zones are positioned in opposite cardinal directions from the core living areas, providing usable outdoor space at different times of day and across seasons. When designing a hillside lot layout, this orientation strategy compensates for the limited flat area that sloping sites typically offer.
Four-Season Outdoor Usability
The strategic placement of outdoor zones on opposite sides of the building envelope means occupants can seek sun or shade depending on the season. In summer, the north-facing deck provides cool respite during afternoon heat while the south-facing patio captures morning sun for breakfast seating. In winter, the south-facing deck becomes the preferred outdoor space, soaking up low-angle sun that the north deck cannot access. This approach to outdoor zoning does not require moving furniture: each zone is furnished for its optimal season and time of day, and residents move between them rather than rearranging a single outdoor space.
Door-to-ceiling openings, which extend from finished floor to the underside of the deck above, maximize the aperture between interior and exterior. Sliding or folding glass door systems with tall profiles allow openings 8 to 10 feet high, compared to the standard 6-foot-8-inch door height common in conventional construction. These tall openings make the transition between inside and outside feel nearly seamless, especially when interior floor finishes continue onto the deck without a threshold change.
Natural Daylighting with Skylights and Glass Walls
Natural daylighting is a defining feature of this hillside modern home. Beyond the perimeter glass walls, the design incorporates skylights over the study and bathroom shower, bringing light into the interior zones that perimeter windows cannot reach. For homeowners exploring how cottage-style modern living handles natural light, the contrast between the compact footprint and expansive fenestration offers useful lessons about scale and aperture.
Skylight Placement Strategies
| Room Type | Skylight Type | Light Well Depth | Daylight Factor Target |
|---|---|---|---|
| Study / home office | Fixed, tubular or rectangular | 1-3 ft | 3-5% |
| Bathroom shower | Fixed, frosted glass | 2-4 ft | 2-4% |
| Interior hallway | Tubular daylight device | 4-8 ft | 1-2% |
| Stairwell | Ridge or curb-mounted | 6-12 ft | 2-4% |
Skylight performance depends on orientation, glazing specification, and the geometry of the light well connecting the roof opening to the ceiling below. A south-facing skylight admits the most total light but can cause glare and overheating in summer unless specified with a low solar heat gain coefficient (SHGC below 0.30). North-facing skylights provide the most consistent, glare-free illumination throughout the year. East and west orientations admit strong morning or afternoon light that may require diffusion. Tubular daylight devices, which use a reflective tube to channel light from a small roof dome to a ceiling diffuser, work well in tight spaces like hallways and closets where a full skylight frame would be impractical.
Wooden Shutters for Light Regulation
Inside the home, wooden shutters provide adjustable light control without blocking the view when fully open. Unlike curtains or blinds that gather dust and block the window frame when retracted, shutters fold neatly against the window casing. The operable louvers allow residents to fine-tune incoming light from fully open to completely closed, with intermediate positions that diffract light into striped patterns across interior surfaces. This level of control is especially valuable in rooms with large glass walls, where unmitigated sunlight can cause glare on screens and discomfort during certain times of day.
Optimizing a Minimal Building Footprint
The technical challenge of this hillside residence was achieving generous, flowing spaces on a relatively small building footprint dictated by the steep slope. The architects resolved this tension through an open floor plan that eliminates interior partitions wherever possible, allowing the living room, dining area, and kitchen to occupy a single volume. The sunken living room adds spatial definition without a full wall, using the change in floor level to create separate zones within the open plan.
Built-in furniture further maximizes usable space. A fixed sofa in the sunken living room eliminates the clearance required for movable furniture placement while ensuring seating is always available. This approach, seen in other modern residential architecture projects, trades flexibility for spatial efficiency. The tradeoff works well in homes where the layout is carefully planned around the owners’ habits rather than designed for resale to an unknown future buyer.
The bi-level kitchen island with a tile countertop continues the space-saving strategy. The lower level provides standard counter height for food preparation, while the raised section offers bar-height seating that does not interfere with the work surface. This eliminates the need for a separate breakfast bar or casual dining table within the kitchen footprint.
Understanding how a minimalist architecture approach handles spatial constraints provides useful perspective for homeowners and architects tackling difficult sites. The combination of concrete, glass, and wood in a carefully organized plan demonstrates that challenging topography does not limit design quality. With proper foundation engineering, strategic daylighting, and thoughtful material selection, a sloping site can produce a home that feels more spacious and connected to its surroundings than any flat-lot alternative.