Three. Four. Three thousand. Thirty-five. Fifty thousand. Each are numbers that can be used to evaluate a house design. Three are currently on the books as town regulations; the other two are not. Several of these numbers turn out to be subject to interpretation and dispute. None of the five, of course, communicate anything about what a proposed house design actually looks like. Let’s look at the first two, then go on to the others in the days to come.

Three, the numbers of acres required for a lot of record, is unambiguous and well-established on Block Island. However, these lots of record are in the minority. The majority of the island’s actual lots are less than three acres. There is certainly potential here for oversight, since non-conforming lots can be treated differently from those of three acres or more.

Four, the per cent of a lot’s buildable area that can be filled by the so-called “footprint” of a building design, is also encoded in town regulations. (The footprint is the top-down size of the structure; it is what it looks like to Google Earth and is usually synonymous with the square footage of the foundation.) Four per cent of a minimum three-acre lot is an enormous number: more than 5,000 square feet. Considering that a house can go three stories, such a number has no real-world impact.

On Block Island, however, with its non-conforming lots and extensive wetlands, the four per cent number does come into play. Wetlands and the 50-foot collar around them are subtracted from the gross acreage. Developers pushed recently to get some of this space back into the four per cent calculation but the town, to its lasting benefit, resisted this weakening.

On the other hand, the four per cent number, used blindly, can act against the best interests of the island. Four per cent of the smallest island lots is a tiny number and it acts like a fist on a tube of toothpaste. Squeeze the footprint and there’s no place to go but up. A house that would be more respectful if it were longer and lower is forced into the mushroom category.

Tomorrow: Three Thousand.