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Residence for Florence and William Tsui
Berkeley, California USA

Owners: Florence Tsui
Location: 2747 Matthews St., Berkeley, California USA
Date: 1993-1995 (Design and construction)
Total Cost: $250,000.00
Square Footage: 2000 square feet

This structure is based upon the world's most indestructable living creature--the Tardigrade, with its oval plan and parabolic top it utilizes the same structural principles nature employs in creating an astoundingly durable design. Internationally touted as the world's safest house it features an oval reinforced concrete foundation over a series of large perforated drain pipes that immediately dispel any water built up and heaving from the soil or sudden flood conditions. Water is immediately taken out through a large storm drain. The house is partially buried in the soil about 1.5 meters and the walls are made of recycled styrofoam and cement block called "Rastrablock". It is impervious to water, fire, termites, has a 40+ R-Value rating and reduces sound by 50 decibels. It is also 10% less expensive then conventional framing construction and much less labor intensive since the blocks are simply glued together, rebar placed inside and concrete poured in. The upper structure is a series of parabolic arches connected by stressed wood sheathing and sprayed with reinforced concrete tied into the recycled block system creating a continuous, unified shell. A series of black flex tubing is placed on the roof to act as passive solar warm air vents. The house has proven itself to be cool in the hot summer months and warm in the cold winter months, all without mechanical air conditioning and heating machinery. A 5 meter diameter south-facing window acts as a light and heat (winter) magnifier to provide light to the central 10 meter high rotunda living area. From this open rotunda light and heat is distributed to the rooms of the house at two levels. Inside, the house contains three ever-deepening levels at the ground floor. The house grows more spacious the deeper one walks into it. The core living area features a suspended spiral ramp with steel cables radiating from the roof skylight. The 220+ square meter house contains a living/conversation area, a recreation room, music/study room, laundry, kitchen and antique display area, three bathrooms, three bedrooms, continuous hallway cabinets, sunken outdoor patio and garden. All but three of the windows in the entire house are openable. All shelves and cabinets are built into the structure of the house and cannot be broken apart in an earthquake. All forms are curvilinear for safety and ease of passing. Every part of the house is interconnected structurally with every other part of the house. The structure disperses stresses and strains that act upon it unilaterally. Manually operated opening and closing "Nostril" windows let in fresh air without letting in insects. Its aerodynamic shape also prevents fire, carried by wind, from adhering to its surface, helping to prevent fire.

Construction Materials: Concrete, styrofoam/cement block, "Hardwall" structural plaster, Stucco, Non-toxic waterproofing, acrylic, marine fiberglass, douglas fir, recycled wood, birch veneer plywood, "Opalina" irridescent paint and rich gold exterior paint

Special Features: The house is a precise ellipse in plan and contains four bedrooms, three bathrooms, a circular living room, sunken outdoor patio and carport. The two story structure utilizes a unique system of recycled styrofoam and cement blocks reinforced with steel and concrete. This material called, Ener-grid Block, is lightweight, fireproof, waterproof, termite-proof and extremely earthquake resistent. Structurally the block creates a reinforced lattice structure, very much like the skeleton of the Cholla cactus. Stress and strain forces are distributed equally throughout the lattice network. The continuous elipse wall forms an extremely durable shell chosen because of its properties of lateral rigidity.

Foundation consisting of Ener-grid recycled styrene/cement blocks.

The walls of the house are angled inward at 4 degrees to create a compressive structure with a low center of gravity; further aiding in resistence to lateral turn-over forces produced by strong earthquakes. This approach to structure has proved to be superior to the box configurations that is typical of buildings of the past. The curvilinear continuity of the ellipsoid form distributes loads in a dispersed manner tangent to the surface, thereby preventing point loads which are potentially destructive to the structure as a whole. This approach to structural integrity increases the internal strength of the frame while minimizing the surface area. By contrast, the box frame is poor at negotiating point loads because it needs supplementary reinforcing to resist tangential forces. In addition, the joints are at greatest risk because stress and strain forces stagnate at the corners requiring further rigidification and bracing to prevent the natural tendency to skew.

Construction of the circular ramp using douglas fir 2x4s.

Another advantage of the Tsui house design is that the exterior walls, being curved, deflect and accelerate wind currents around the surface preventing the vacuum suction phenomenon, so prevalent in flat plane surfaces, from occuring. The dimpled surface further enhances the efficiency of the aerodynamic shape by relieving wind friction. One of the most pronounced dangers of flat surface buildings are their ability to draw fire to themselves. Flat planes are fire targets in a high-risk fire area where winds are unpredictable. When a flame-carrying breeze contacts a flat surface it creates a small vacuum on that surface. This vacuum sucks fire onto the wall and accelerates the process of flame spread. By curving the walls, as in this design, this vacuum effect cannot occur and winds and flames are taken away from the surface helping to prevent flame build-up. For the Tsui house design an additional ring of four water jets immerse the exterior of the house in the event of a neighborhood fire. This precaution renders the house virtually fire-proof from the outside.

The placement of sub-surface tubes are used to create a self-sufficient radiant heating system.

The design program approached the house as a living organism capable of actively responding to various natural elements of the site. A prominent example of this is the subsurface solar water tubes that are positioned to correspond to the sun-ray like exterior motif that covers much of the upper level of the house. Water in the black tubes is heated by the sun throughout the day. At night the stored heat is radiated back into interior of the house walls and provides radiant wall heat. This subsurface solar heating system was conceived by studying the bone and capillary structures of two dinosaurs, the Dimetradon and the Stegosaurus. Both reptiles utilized a form of biological solar heating by way of the large sail-like structure on the back of the Dimetradon and the series of plate structures on the back of the Stegosaurus. In both these ancient reptiles the plate structures were surrounded by a very packed configuration of blood veins. The sun heated up these veinfilled plates and helped to regulate the body temperature of these reptiles. Thus a form of living solar heating was being practiced 150,000,000 years ago.

The continuous curvilinear form of the building maximizes the capacity of the exterior surfaces to drain away water, particularly when the exterior jet sprinklers are activated. For this and other reasons the house contains no eaves, soffits, shingles and related architectural features common to traditional buildings. Waterproof sealant is used both as an admixture to the cement plaster exterior as well as separate surface coating. The styrofoam/cement blocks render the house impervious to termites.

View of the central sitting area, and circular ramp.

On the interior there exists no stairs--the multiple levels inside the building are reached by a series of ramps which culminate in a central circular ramp at the midpoint of the house, figure 10. The name of the house "Ojo Del Sol" (The sun's eye) or Tai Yang Yen, in chinese, comes from the eye-like "oculus" window, fifteen feet in diameter, facing south, which disperses sunlight inside the house and warms the floors surface. In the daytime the floor absorbs this solar heat. At night it radiates into the spaces within.

The circular "oculus" window on the south-side of the building disperses sunlight into the house to warm the floor surface.

The ground level is three feet below grade to make insulation more effective. Three levels divide the ground floor into three living zones. The upper floor level features a series of specially designed trusses modeled after seagull bone marrow. The challenge here was to create an overhead truss system that minimized material usage, was extremely lightweight for ease of transporting and placement, and was very strong. In nature, an ideal candidate for fulfilling these requirements was the seagull bone. The bone is comprised of a series of angled struts integrated to the bone surface from bottom to top. By minimizing the number of struts and open space the seagull bone becomes a wonder of natural engineering. By understanding the principle at work in the bone we are able to solve the problem of material/weight efficiency without having to resort to the convenient but inefficient use of premanufactured beams and struts.

View of the central sky-light above the circular ramp

Owner Requirements: Maximize the usable square footage of the lot (35 feet wide by 100 feet long with a 28 foot height restriction). No stairs. Four bedrooms. Three bathrooms. A place to park a car. Privacy from neighbors. Lots of light. Conserve heatings and cooling bills wherever possible. Absolutely waterproof foundation. Minimize or eliminate grass areas. Fans in all bathrooms. A place to display art items. Do not go over budget. Spaces open to one another.

View of the bas wall relief in the master bedroom

Ecological Requirements: None. The owners were gradually educated about the benefits and advantages of a nature-based, ecological approach to designing their home. They grew to support this ecological attitude especially if it meant a cost savings and a simper way of maintaining the home.

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