How many square feet in the average microhousing unit? It depends on who you ask……

If you read the online articles, you will frequently see figures of 150-200 square feet, with 200 being a frequent average. They never say where they get these averages.

The Department of Planning and Development gives an estimate of 257 square feet per unit on average. When I inquired as to how they arrived at that estimate, they said it was the figure generated by dividing the total square footage of a project by the number of estimated units in a project. This would result in a higher than average square footage, as it does not make adjustments for corridors, stairways, utility areas and common areas. The DPD’s average is not credible and cannot be relied on.

My thorough examination of drawings for microhousing projects showed the following:

Of 1751 total units, the drawings do not contain sufficiently fine-grained information to determine the size of 767 separately leasable units. Some of the projects do not yet have drawings prepared and submitted. None of the drawings specify whether the square footage is net (minus corridors and stairways) or gross. Of the 691 units that are marked with a square footage number, 473 or 68.3% are contain less than 204 square feet. Why isn’t the DPD requesting this information on all of the drawings? Mike Podowski says that it is because the DPD doesn’t have the authority to request it.  Seattle City Council should request the DPD to obtain accurate square footage, specified as to whether it is net or gross, for all separately leasable units.

My analysis of all zones showed: 5% of units are under 100 square feet, 22% are under 140 square feet, 57% are under 180 square feet, 80% are under 220 square feet, 94% are under 260 square feet, 99% are under 300 square feet, and 1% are greater than 300 square feet. In an analysis of information I provided to him, Bill Bradburd examined the square footage for the Lowrise 3 zone. In the Lowrise 3 zone, nearly all – 97% –  of the 407 reviewed units are under 220 square feet.

Close analysis provides information that varies considerably from the conventional wisdom.