Home Extension Builder The Hills
Home extension specialists — additions, second storeys and structural reworks on existing homes.
Home Extension in The Hills — what it actually takes in 2026
Extension in The Hills is mid-tier to premium scope across the established suburban stock — 1970s–1990s brick homes on 600–1,200m² R2 lots in Baulkham Hills, Castle Hill, Beaumont Hills, Winston Hills, North Rocks, West Pennant Hills, Glenhaven, parts of Kellyville and Bella Vista. Second-storey additions, rear extensions, granny-flat-scale studios, garage conversions and acreage homestead extensions all common scope. Bushfire-prone overlays on rural west drive specs on extension scope above 50% of original floor area (BAL-29 minimum on most acreage). Tree Preservation Order strict — AS4970 root-zone protection plans routine. Acreage extensions on Kenthurst, Annangrove, Glenhaven, Middle Dural, Maraylya, South Maroota run premium homestead-grade work with sandstone retaining and bushfire spec compliance. Apartment renovations on Norwest, Bella Vista, Castle Hill, Kellyville and Rouse Hill Sydney Metro Northwest precinct R4 high-density stock — restricted by strata bylaws and common-property approval. Castle Hill Showgrounds, Bella Vista Farm and parts of Baulkham Hills heritage cottages carry heritage-grade work. Realistic budget $200K–$500K for thoughtful 50–110m² addition on suburban core; $400K–$900K on Bella Vista/Glenhaven/West Pennant Hills premium suburban; $600K–$1.5M on premium acreage homestead at Kenthurst/Annangrove/Middle Dural; $130K–$400K apartment-scale.
Why The Hills owners choose Buildana
- Fixed-price contracts referencing the Rawlinsons Australian Construction Handbook 2026 (Sydney column) — no estimate-only quotes that climb mid-build.
- In-house design and approvals coordination — DA, CDC, heritage, bushfire BPA, Coastal Management referrals all handled.
- Site investigation at proposal stage — soil, slope, sandstone, BAL, heritage and tree-protection assessment so the contract sum holds.
- Asbestos assessment and SafeWork NSW–compliant removal included on every pre-1990 stock project as standard.
- Owner-led project management — Oliver Alameri (NSW Builder Licence) signs every contract and runs every job.
Ready to talk home extension in The Hills?
Book a free site assessment with Oliver Alameri. We'll cover soil, slope, council overlays, realistic 2026 costs and the planning pathway for your block.
Home Extension The Hills — frequently asked questions
Do I need DA approval for a home extension in The Hills?
Most extensions exceeding 50m² floor area or altering envelope require DA in The Hills. Smaller compliant additions may use CDC fast-track. Heritage Conservation Areas require DA regardless of size. Buildana assesses your scope at proposal stage and provides the planning pathway in writing.
What does a second-storey addition cost in The Hills?
Second-storey additions in The Hills typically run $300K–$1.4M depending on footprint, structural reinforcement to existing footings, heritage overlay, and finish specification. Buildana provides fixed-price contracts after structural assessment.
Can I stay in the home during construction?
Most ground-floor rear extensions can be staged so you remain in the existing home during major works. Second-storey additions usually require temporary relocation for 4–8 weeks during structural and roofing works. Buildana confirms the staging plan at contract.
Other services across The Hills
Neighbouring Sydney LGAs we build in
We work right across the Sydney basin. If your block sits on the boundary of The Hills, or you're comparing options in a neighbouring council area, here are the closest LGAs we cover with the same depth of local knowledge.
We build across every Sydney LGA
Buildana works across all 28 Sydney metropolitan LGAs. Pick the council area your block sits in for a deep-dive on local soil, heritage controls, DCP rules, and realistic cost ranges.
Western Sydney
South-West Sydney
Inner West & River
North Shore & Beaches
Eastern Suburbs