Cosgriff House | Christopher Polly Architect
Annandale, NSW, Australia

James Lyall Smith

Project Type
  • Residential
  • Annandale, NSW, Australia
Lead Architect
  • Christopher Polly
Interior Designers
  • 167m2
Project Year
  • 2013
  • Brett Boardman
  • Gregson Constructions
Structural Engineer
  • SDA Structures
Hydraulic Engineer
  • ACOR Consultants
  • Damian O’Toole Town Planning
  • Junek & Junek
  • Annandale, NSW, Australia

The Cosgriff House Project by Christopher Polly Architect is a substantial lower ground room that has been inserted under the original fabric, harnessing the fall in the site towards the rear.

The room extends deeply beneath the existing dwelling and outwards towards the garden to transform the original dwelling in combination with the re-crafted rear of the ground floor above.

Both levels accept a modestly-sized lightweight addition which extrapolates existing wall alignments, gutter levels and enclosing wall heights – that at once, extends and subverts existing geometries to present an interpreted mirrored slice of the original vernacular form extant vernacular tectonic form and palette attached to the retained rear fabric.

An eccentric roof form extrapolates the original southern roof plane to mitigate adjacent impacts – lifting to light and tree views to the east, while also folding upwards for access to northern light and sky through a sole fire-rated window along the boundary.

The project retains its original envelope and significant portion of its ground floor fabric as part of its overriding environmental and economic sustainability objectives. New work is substantially embedded within the existing footprint, with only a modestly-sized 20sqm addition to the rear.

Vaulted ceilings and skylights carved within the original roof form expand volumes for access to light and sky within the middle of the ground floor – while a stair hall, cantilevered balcony and generous void spatially expands to the lower level below, and upwards to views of the external environment to strengthen connections to its setting. Fenestration placement improves natural light access and promotes passive ventilation, assisted by ceiling fans and a roof venting system to exhaust trapped heat out of the original roof space.


2014 Architizer A+ Awards – Shortlisted Finalist

2013 BPN Sustainability Awards – Shortlisted Finalist


2013 Houses Awards – House Alteration & Addition – Shortlisted Finalist

2013 Australian Interior Design Awards – Shortlisted Finalist

To view more Christopher Polly Architecture and Interior Design Archives head to his TLP Designer Profile.        

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Brett Boardman

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