(dissenting, with whom Ireland, J., joins). I agree with the court’s conclusion that certain “small-scale alterations, *364extensions, or structural changes to a preexisting house” could not reasonably be found to increase the nonconforming nature of a house whose only nonconformity is that it is located on a smaller lot than what the town’s zoning bylaw now requires as a minimum for future residential development. Ante at 362. I continue to disagree, however, with the court’s conclusion that the reconstruction and enlargement of an existing single family residence that fully complies with current zoning and building size requirements, except minimum lot size, “increase[s] the nonconforming nature of [the] structure,” such that the grandfathering provisions of G. L. c. 40A, § 6, first par., provide it no protection. Ante at note 3. My disagreement with the court’s reasoning is set forth in the dissenting opinion in Bransford v. Zoning Bd. of Appeals of Edgartown, 444 Mass. 852, 863 (2005) (Bransford) (Cordy, J., dissenting, with whom Ireland and Sosman, JJ., joined), and need not fully be repeated here.
It does bear repeating, however, that the size of residential structures is not regulated by minimum lot size requirements. Rather, a town may (among other things) impose setback requirements, height restrictions, and even lot coverage ratios for this purpose, as apparently the town of Norwell does. Thus, while a preexisting residential structure that exceeds building size requirements may remain pursuant to G. L. c. 40A, § 6, first par., any attempt to alter, reconstruct, or extend the structure in a manner that would increase its size would plainly “increase the nonconforming nature of [the] structure,” thereby removing such an alteration, reconstruction, or extension from the protection of the statute and requiring a special permit.
Minimum lot size requirements are, however, of a different nature. They limit the number of dwellings that can be built in a town, thereby limiting the density of the population, and most particularly the number of families who may reside there and the burden such families place on town services (such as schools, sewers, and public safety). A home on a lot that has become nonconforming because of an increase in minimum lot size is not nonconforming because of the size of the structure. The nonconformity is that there is a dwelling on the lot at all. Whether the dwelling is 675 square feet or 3,500 square feet is irrelevant to the nonconformity of its lot — the latter is as nonconforming *365as the former. Consequently, increasing the dwelling’s size (so long as permitted by current setback and other building-size requirements) cannot be said to increase a nonconformity that has nothing to do with building size. There will still be one, and only one, dwelling on the property.
For these reasons, and those regarding what I perceive to be the Legislature’s intention to provide greater protection for the owners of single-family and two-family homes (as discussed in the Bransford dissent), I respectfully dissent from the court’s interpretation of the statute to the contrary.