Hornsby Shire Council
Private building certifier in Mount Colah
Mount Colah has homes from several eras, from railway settlement to 1960s public housing and 1980s villas. We match each project to your lot’s zone, house age and layout.
NSW 2079
Class 1 homes and Class 10 structures
Local rules
Layers of Housing in Mount Colah
A layered history
Trains first stopped here in 1887, at a station then called simply Colah. Public housing arrived in the 1960s, and villa developments appeared on the western side in the 1980s. That gives the suburb a mix of building ages and construction types. A 1960s home may be built quite differently from a 1980s villa next door, so check how the house was built before drawing an addition.
Mostly detached homes
The 2021 Census counted 7,816 residents in 2,820 private dwellings. Stand-alone houses accounted for 83.9% of occupied homes. Flats were 12.3%, and townhouses or semis about 4%.
Highway precincts
Hornsby's DCP names precincts along the Pacific Highway twice: once for medium-density housing and again for five-storey buildings. Each has its own design diagram. Part 4 adds a masterplan for the town centre. These apply only to mapped land, not to every residential street. Sites next to the railway or the highway may also need design responses to noise and vibration.
Typical work
Common projects and how they get approved
What owners build here
Most Class 1 and 10 work here involves detached houses.
- Rear additions. On older homes, plan how the added rooms join the original structure while leaving a usable yard.
- Garages and carports. Check setbacks and how the driveway meets the street.
- Decks. A raised deck needs careful checks on height, privacy and how it joins the house.
- Pools and roofed alfresco spaces. Plan them with the landscaped area in view.
- Granny flats. Possible where the lot, house and design meet the rules.
- Villa alterations. Check party walls, the shared driveway and the strata boundaries first.
Apartment buildings and shops are outside Class 1 and 10, so they need a different certifier.
How approval usually works
A rear addition, garage, pool or granny flat on a standard housing lot often suits a CDC, a quick approval issued by a certifier. Other projects need a DA from Hornsby Shire Council, and the CC comes after consent.
Do not assume a highway precinct envelope applies just because your home is near the road or station. Check your zone, any state housing rules and the right diagram first. For a villa, get the strata plan and approved layout, because a change to one home can affect the next. Send a survey, photos and your planning certificate. If the house is older, include any past approvals you hold, since earlier unapproved work can delay a new certificate. CertifiBuild can help you choose a clear path for your house project.
Our services
From approval to sign-off.
One certifier for your whole Mount Colah job, from the first plan check to the occupation certificate.
Local questions
Questions we hear about this suburb.
No two lots in Mount Colah are the same. Give us your address and we will check every map that affects it.
See the council pageDoes the Pacific Highway precinct cover my Mount Colah house?
Only if the map takes in your lot. Hornsby’s development control plan (DCP) names Pacific Highway precincts twice, once for medium-density housing and once for five-storey buildings, and gives each a design diagram, and Part 4 adds a town centre masterplan. They apply only to the mapped sites, whatever your distance from the road or station. Check your zone, any state housing rules and the right diagram before comparing your house with a local apartment building. Homes beside the railway or highway may also have to deal with train or traffic noise and vibration in the design.
Can I add a granny flat behind my Mount Colah home?
Often, provided your block, the current house and the new design all satisfy the rules. On a standard housing lot, a granny flat often suits a complying development certificate (CDC). Otherwise Hornsby Shire Council assesses a development application (DA). Look at access, landscaped area and services together rather than one at a time. The apartment precincts near the highway neither block a granny flat elsewhere in Mount Colah nor show that your own yard has room for one. Send a survey, photos and your planning certificate, plus past approvals if the house is older.
Is a Mount Colah villa renovation treated like a house project?
Not exactly. Many of Mount Colah’s villas date from the 1980s on the western side, and they can share walls, driveways or strata land with their neighbours. Ahead of any deck, carport or extension, get the strata plan and the approved layout to confirm which parts are yours. A change to one villa can affect the next, through party walls, drainage or the shared driveway. The owners corporation may need to agree as well. With ownership settled, we can match the job to the right controls and approval path.
Building in this suburb?
Send us the address first.
We check the local maps for your lot, confirm the approval path and quote in writing.