usually approval required is planned for major extension (such as kitchen extension to backyard) which affected the actually house design as show S&P... but as your case just to wall up the balcony only without extension should no approval required...

as for townhouse have no idea, because so far i never saw any single of apartment/condo walled up their balcony as their own living space... perhaps refer ur S&P, Deed Of Mutual (if any) or other related documentation whether have any clauses that no allowed the change the house exterior design, color, etc... but by sense should no allowed for such renovation as the same townhouse land sharing with few owners, which same as apartment/condo...

This post has been edited by gkl83: May 16 2011, 01:55 PM