I visited Roger Conrad, a neighbor across the way on Sulphur Mountain, on Sunday morning and toured his new dogtrot house that he has been building for a year or more. It's closed up and awaits stucco.

On Saturday evening I chatted with Leon Berg at a reception at The Beatrice Wood Center for the Arts for The Rangoli Dance Company. Leon is the expediter-cum-project manager for the Besant Hill School Pool project which includes boys and girls changing rooms. Originally designed as a butterfly roof structure the changing rooms were split asunder in order to skirt the County's fire-sprinkler requirement - the two buildings being less than the minimum size requiring sprinklers. The two shed roofed structures are now designed to be 10' apart providing a kind of dogtrot-like breezeway between them.

Roger's house is a variation on the Shotgun typolgy: a long thin house type popularized in New Orleans and originating under a tax code that was based on a building's frontage. Minimising the width and extending the length was thus the most efficient strategy in terms of tax liabilty. Avoiding the installation of an expensive sprinkler system has been the driver for the bifurcation of the dressing rooms into two separate pavilions.

Thus it is that design develops as a direct result of tax-policy, legislation or municipal codes. Constraints are good for design. I have often credited the California Building Code as my co-designer - not entirely in jest. Certainly the energy provisions under Title 24 have a dramatic influence on the design of fenestration, and shear wall requirements - made more restrictive after the 1994 Northridge earthquake - can provide a major design impetus.

The two issues that prompted Roger's design were the need to provide natural cooling (as an off-the-grid project utilizing a limited photo-voltaic array Roger could not afford the energy use of air-conditioning) and audio privacy between both ends of a small house. Roger's wife Ruthie Marks, the crochet designer, is a great baseball fan and Roger is allergic to the 'soundtrack to summer' provided by Vince Scully and others. As a child I loved listening to Test Match cricket with soothing voices of John Arlott, Richie Benaud and Brian Johnston. In Australia I enjoyed listening to Rugby League with the incomparable Frank Hyde (1916-2007) providing the commentary. I even enjoy listening to Vince Scully on occasions, but quite understand Roger's aversion.

The screen porch which divides the kitchen living and dining end of the house from the two bedrooms/offices solves both these design constraints and does so in a way that has the imprimatur of tradition - always a useful ally in architectural design- and makes his house typical of the dogtrot typology.

We met early on Sunday because Roger was driving down to Malibu for a re-union with Peter Jon Pearce and their colleagues. Pearce had headed up a major design and engineering firm (Pearce Structures) in the latter part of the twentieth century and was involved in many mega-structure projects throughout the world most notably perhaps, the design of the superstructure for the Biosphere II. Bits and pieces of prototype glazing systems still litter Roger's yard from his time on that project.

Pearce is now focused on his own 'Ecohouse' the prototype of which he plans to build on a few acres in Malibu. Ultimately he envisages a community of 'Ecohouses'. Later that morning, having looked at Pearce's web-site it was fascinating to consider Pearce's contribution to the genre in light of my own house and my visit to Roger's new home - both after all could claim to be eco-houses. Pearce suggests that his Ecohouse "takes solar design, green design, green architecture and pre-fab building beyond green, beyond pre-fab."

But first he needs to design the tooling for the space frame struts and knuckles that will form the armature for the 'Climate Management Canopy' that "intercepts solar radiation...and incorporates solar panels and solar thermal collectors''. Roger and I utilized a climate management canopy in our eco-houses, but we refer to them as walls and a roof. Pearce uses his exo-skeleton to shade what is essentially a glass box which assures abundant natural light and ventilation. We used windows.

Pearce suggests that his project "comprises a paradigm shift, which is intended to further the goal of contributing to the sustainability of the built environment through the implementation of a high performance design ethic". The pay-off for Pearce's Ecohouse is "a carbon-netral footprint by means of a net-zero energy use on an annualized basis". We just achieved that with our grid-tied photo-votaics and Roger has been living 'off-the-grid' these many years without recourse to Edison's help or accounting.

I should point out that the cynicism with which I view Pearce's endeavor is all mine. Roger told me of the projected Malibu Ecohouse in order to share his enthusiasm for a bravura engineering exercise and to touch on his own background as an engineer.

On a more prosiac level, Roger has achieved the great feat of persuading Ventura County to sign-off on an 'off-the-grid' residential project. His engineering background has been put to solid use designing his photo-votaic array and storage system as well as the water systems to support sprinklers, a draft hydrant and domestic supply. Constrained by budget and lacking any vestige of architectural ego or bombast he has (with designer Jane Carroll's able assistance) devised a modest but supremely 'green' house.