[Massplanners] can a small primary dwelling become an ADU?

[Harry LaCortiglia]

Hi Bill,

Assuming that the owner first builds a small principal dwelling of less 
than 900sf, how can they then be permitted to build anything larger than 
450 sf?

The regs state that the ADU :

/(b) is not larger in Gross Floor Area than ½ the Gross Floor Area of 
the Principal
Dwelling or 900 square feet, whichever is smaller;/

Am I misunderstanding something from the regs that allows the build of 
an ADU that's _larger_ than the principal dwelling?

Best,

H. LaCortiglia
Georgetown P.B.

On 1/30/2025 10:33 AM, William Cole via MassPlanners wrote:
> An owner of a vacant parcel (and our Planning Board) needs to know if 
> a small (less than 900 sf) primary dwelling could be built first, then 
> later a larger primary dwelling be built while declaring the first 
> dwelling to be the ADU.  The end result would be the same as if the 
> larger dwelling had been built prior to the smaller one.  I asked for 
> and suggested clarification on this point when the legislation was 
> being finalized, but got response.  Thanks for any thoughts on this.
> Bill Cole
> Hardwick MA PB
>
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