Mosman · Rear Extension

Open up the rear of your Mosman home without guessing the approval path.

GY & Co checks the land, slope, access, drainage, heritage signals and CDC/DA pathway before detailed design begins.

Mosman rear extension living space

Ground-Floor Extensions

The hard part is not just adding floor area.

In Mosman, rear extensions often need careful thinking around views, neighbours, slope, drainage, side access, mature trees and older building fabric. We test the practical constraints first, then shape the design around what can realistically be approved and built.

  • Rear extension and open-plan living strategy
  • CDC / DA pathway checked before drawings go too far
  • Site access and construction practicality reviewed early

Mosman FAQ

Questions before building out

Can I build a rear extension in Mosman?

A rear extension may be possible in Mosman, but the site needs to be checked first. Slope, heritage, trees, stormwater, privacy, access and Mosman Council controls can all change the answer.

Is a Mosman rear extension usually CDC or DA?

It may be CDC only if all complying development rules are met. Many Mosman sites need DA because of heritage, slope, views, privacy, stormwater or other constraints.

Start Here

Check your Mosman extension feasibility before drawings.

Check Extension Feasibility