Best renovation and extension builders in Mosman (2026): thirteen compared

Short answer

For a renovation or extension in Mosman, owners can start with businesses that show completed Mosman work on their own sites, such as Andvic (an extension and a period-home renovation), Cumberland Building Projects (a heritage restoration), Kongstruction (a 2020 remodel) and Domus Homes (a renovation and addition, managed with a network of builders). For second-storey additions, The Perfect Space Design + Build, Next Storey Home Additions, AGATHĒ Builders, Buildscope Projects, Pearson Industries and Emerald Projects state them for Mosman, while LikeSilk Building and Hall & Hart focus on renovations. AUD Build (this is us) completed a new house in Mosman, and its alterations-and-additions approval is in Clontarf. Mosman has 13 heritage conservation areas, where complying development limits external alterations; BASIX applies to alterations of A$50,000 or more; and Mosman Council averaged 80 days to assess a DA in September 2026.

Local rules and figures

At-a-glance comparison

Facts from each business’s website, read 28 October 2026. Alphabetical order, not a ranking. AUD Build publishes this page.

The 13 compared

1. AGATHĒ Builders

Best for: Owners adding a living room, master suite, second storey or garage conversion who want the builder to design and build the addition.

What its website says:

• Its Mosman extensions page designs and builds additions, from a new living room or master suite to a second storey, alfresco or garage conversion.
• Describes builder-led delivery, managed end to end, and also builds custom homes and Passivhaus homes.
• Its website shows NSW Builder’s Licence No. 463967C.

Area: Has Mosman pages for custom extensions and home renovations

Sources: [11] [12] [13]

2. Andvic

Best for: Owners of a Mosman period home who want an architect-led extension or renovation from a builder that shows completed Mosman work.

What its website says:

• Lists a completed Mosman home extension among its projects.
• Its completed Mosman period-home renovation, with a named architect, balances heritage with contemporary living.
• Says it specialises in design-led residential projects, including renovations and additions; office in Macquarie Park. No licence number was shown on the pages read.

Area: Shows two completed Mosman projects: a home extension and a period-home renovation

Sources: [14] [15] [16]

3. Buildscope Projects

Best for: Owners planning a luxury renovation, architectural extension or second-storey addition in Mosman with a licensed builder.

What its website says:

• Its Mosman page lists luxury home renovations, architectural home extensions and second-storey additions.
• Says it has over 10 years of experience in residential and commercial construction.
• Builders licence number 326491C. Its suburb pages use one template.

Area: Mosman page for renovations, extensions and second-storey additions

Sources: [17]

4. Cumberland Building Projects

Best for: Owners of a large Mosman heritage home who want a builder that shows a completed restoration of one.

What its website says:

• Its Mosman project was a comprehensive restoration of one of Mosman’s grand merchant heritage homes.
• Also shows a new three-split-level home in Mosman.
• Its website shows Builders Lic No. 84913C; extensions are not stated as a separate service on the pages read.

Area: Shows a completed restoration of a Mosman heritage home

Sources: [18] [19]

5. Domus Homes

Best for: Owners who want one party to manage the design and construction of a renovation and addition, built through its network of builders.

What its website says:

• Its project page covers a house renovation and addition in the Mosman Council area.
• Says it has completed renovations, extensions, alterations and first floor additions, and names Mosman among the suburbs it lists.
• Describes design and construction project management that works with a network of builders; no builder licence number was shown on the page read.

Area: Shows a house renovation and addition in Mosman

Sources: [20]

6. Emerald Projects

Best for: Owners of an older Mosman house planning alterations who want a builder that discusses heritage documents and period fabric.

What its website says:

• Lists home extensions, second-storey and first-floor additions and home renovations on its Mosman page.
• Its Mosman page focuses on heritage alterations, including the heritage impact statement and careful work with period fabric.
• Its website shows NSW licence 476281C.

Area: Mosman page for home renovations and building services

Sources: [21]

7. Hall & Hart

Best for: Owners planning a major renovation who want design, approvals and construction handled by one in-house team.

What its website says:

• Says it designs and delivers major home renovations across the North Shore.
• Its portfolio includes Mosman Maison, a completed Mosman home shaped around the area’s heritage context.
• One in-house team handles design, approvals and construction; Builders Licence 275897C. Extensions are not listed as a separate service on the pages read.

Area: Mosman is among the North Shore suburbs its projects span

Sources: [22] [23]

8. Kongstruction

Best for: Owners who want to see a Mosman remodel before choosing a builder for a kitchen, bathroom or whole-house renovation or an extension.

What its website says:

• Its Mosman page has sections on home renovation and home extension in Mosman.
• Its 2020 Mosman project was an extensive remodel that took out the kitchen, bathroom and en-suite.
• Office in Auburn. Its suburb pages use one template.

Area: Mosman page; shows a 2020 Mosman remodel

Sources: [24] [25]

9. LikeSilk Building

Best for: Owners of a Mosman heritage home who want a family-run builder for bathroom, kitchen or full interior renovations.

What its website says:

• Handles bathroom, kitchen and full interior renovations across Mosman and the North Shore.
• Says it is experienced with Mosman heritage homes and conservation areas.
• Family-run; licence 274849C and HBCF insurance shown. Extensions and first-floor additions appear only in its site menu, so they are not counted here.

Area: Mosman area page covering bathroom, kitchen and full interior renovations

Sources: [26]

10. Next Storey Home Additions

Best for: Owners who want a second-storey or first-floor addition from a business that focuses on adding storeys.

What its website says:

• Lists second-storey extensions, first-floor additions, home extensions, renovations and attic conversions.
• Says it has over 10 years of experience delivering second-storey building services.
• Office in North Manly; no licence number was shown on the pages read. Its suburb pages use one template.

Area: Mosman page for home extensions and second-storey additions

Sources: [27] [28]

11. Pearson Industries

Best for: Owners of a Mosman period home who want a heritage renovation or a single or second-storey extension that blends with the house.

What its website says:

• Offers heritage renovations and restorations for Mosman period homes.
• Offers single and second-storey extensions designed to blend with the existing home.
• Its website shows Lic. Number 292515C. Its suburb pages use one template.

Area: Mosman service-area page

Sources: [29]

12. The Perfect Space Design + Build

Best for: Owners planning a luxury renovation or second-storey addition who want it designed and built by one group.

What its website says:

• Says it has delivered numerous renovations and second-storey additions across Mosman.
• A registered architectural partner and interior designers work with its construction team, so an addition is designed and built by one group.
• Says it has over 17 years of experience; Builders Lic 266190C; office in Manly.

Area: Mosman page: luxury renovations and second-storey additions across Mosman

Sources: [30]

13. AUD Build · This is us

Best for: Mosman owners planning alterations, additions or a second storey who want design, materials, construction and lending coordinated by one company, with material unit prices they can check.

What its website says:

• Brings design, construction, building materials, new-home sales and lending together in one company, backed by AUD Build Group; NSW Builder Licence 475778C.
• Services confirmed by AUD Build on 28 October 2026 include renovations and extensions (alterations and additions, second storeys), as well as new homes, knockdown rebuilds, custom and luxury homes, duplexes and granny flats.
• In Clontarf on the Northern Beaches, a DA for alterations and additions was approved on 20 February 2026, and the construction certificate application names AUD Build’s operating company as builder.
• In Mosman, AUD Build Group building companies completed a new house (not a renovation), with the occupation certificate issued in September 2024.
• Materials come from its own supply chain platform, www.audbuild.net, and AUD Build clients can log in to check the material unit prices in their quote.

Area: Completed a new house in Mosman (occupation certificate September 2024); its alterations-and-additions approval is in Clontarf

Sources: [31] [32] [33] [34] [35]

Where each one may suit you

• Completed Mosman renovations and extensions shown on their own sites: Andvic (an extension and a period-home renovation), Cumberland Building Projects (a heritage restoration), Kongstruction (a 2020 remodel) and Domus Homes (a renovation and addition).
• Second-storey and first-floor additions: The Perfect Space Design + Build, Next Storey Home Additions, AGATHĒ Builders, Buildscope Projects, Pearson Industries and Emerald Projects.
• Heritage homes and conservation areas: LikeSilk Building, Pearson Industries (heritage renovations and restorations), Emerald Projects (heritage alterations) and Cumberland Building Projects.
• Kitchens, bathrooms and interiors: LikeSilk Building (bathroom, kitchen and full interior renovations).
• One team for design and building: The Perfect Space Design + Build (registered architectural partner), Hall & Hart (in-house design, approvals and construction) and Domus Homes (design and construction project management through a network of builders).
• Design, materials, construction, sales and lending from one company, with material prices you can check: AUD Build.

How to choose

1. Check whether the house is a heritage item or in one of Mosman’s 13 heritage conservation areas: that decides whether exempt or complying development is possible, or whether you need a DA.
2. For a second storey, check the 8.5 m Housing Code height limit; in a conservation area a CDC cannot increase the height of the house, so a second storey there needs a DA.
3. If the work is valued at A$50,000 or more, BASIX applies; ask who prepares the certificate before the design is finalised.
4. On a waterfront lot, check the foreshore building line before designing a rear extension.
5. If the house was built before 1987, allow time and budget for asbestos testing and licensed removal before walls, kitchens or bathrooms come out.
6. Several pages on this list use one template for many suburbs: ask each builder which Mosman alterations it has completed.
7. Ask every builder to quote on the same drawings and scope of works, and compare inclusions line by line with the inclusions checklist.
8. Check the licence on Verify NSW and the HBC certificate before you pay a deposit.

Questions

Who are the best renovation and extension builders in Mosman?

It depends on the house and the work. For businesses that show completed Mosman work, owners can compare Andvic, Cumberland Building Projects, Kongstruction and Domus Homes; for second-storey additions, The Perfect Space Design + Build, Next Storey Home Additions, AGATHĒ Builders, Buildscope Projects, Pearson Industries and Emerald Projects; for heritage and interior renovations, LikeSilk Building. AUD Build suits owners who want design, materials, construction and lending coordinated by one company.

Do I need a DA to renovate or extend in Mosman?

Not always. Minor work can be exempt development if it meets the state standards (not on State Heritage Register items), and the Housing Code allows alterations and additions as complying development, up to 8.5 m high, with a CDC issued within 20 days. In one of Mosman’s 13 heritage conservation areas a CDC cannot increase the height of the house, so a second storey there needs a DA; Mosman Council averaged 80 days for a DA in September 2026.

Does BASIX apply to my Mosman renovation?

BASIX applies to all alterations and additions in NSW valued at A$50,000 or more, so estimate the value of the work early: at A$50,000 or more you need a BASIX certificate.

Can I extend a house in a Mosman heritage conservation area?

Yes, with limits. Development in or next to a heritage conservation area must be sympathetic to its heritage significance, and under complying development, external alterations to a house in a conservation area must not increase its height. Ask each builder who prepares the heritage documents.

How much does it cost to rent while I renovate in Mosman?

If you move out during the work, the median weekly rent for a house on a new bond was A$2,100 in Mosman (postcode 2088, 56 new bonds) in April–June 2026.

Why is AUD Build on this list?

AUD Build publishes this page and carries out renovations and extensions, including alterations and additions and second storeys. Its alterations-and-additions approval is in Clontarf on the Northern Beaches: a DA approved on 20 February 2026, with AUD Build’s operating company named as builder on the construction certificate application. In Mosman its group completed a new house, not a renovation. It is listed last and marked “This is us”. Facts about the other twelve businesses come only from their own websites.

How this list was built

Selection: businesses whose own websites state renovations, extensions, alterations and additions or second-storey additions on a page that names Mosman, drawn from Google Australia results for Mosman renovation, extension and second storey addition searches and the businesses’ own pages, read on 28 October 2026. A service shown only in a site menu or a bare list of services is not counted. Directories and marketplaces are excluded. Facts come only from each business’s own website, read on 28 October 2026; “Best for” is AUD Build’s editorial summary of those facts. Prices, sale results, reviews and award claims are not published, and a builder’s statements about planning rules are not repeated as fact. Where a builder’s suburb pages use one template, its row says so. The order is alphabetical, not a ranking. AUD Build publishes this page; if a business’s details have changed, contact AUD Build and the page will be corrected.

Sources (all read 28 October 2026)

1. Mosman Council, Low and mid-rise policy FAQ (updated 10 April 2026)
2. NSW Government, Council league table (September 2026 snapshot, as of 9 October 2026)
3. NSW Planning Portal, Exempt development (updated 7 February 2025)
4. NSW Planning Portal, Housing Code
5. Mosman Council, Heritage listings (updated 6 August 2024)
6. NSW Planning Portal, Complying development: home renovation (updated 30 April 2025)
7. NSW Planning Portal, BASIX: alterations and additions (updated 7 May 2025)
8. Mosman Council, Planning controls FAQ (updated 6 August 2024)
9. NSW Planning Portal, Complying development: demolition (updated 30 April 2025)
10. NSW DCJ, Rent tables June 2026 quarter (new bonds, houses)
11. AGATHĒ Builders, Custom extensions Mosman
12. AGATHĒ Builders, Home renovations Mosman
13. AGATHĒ Builders, Granny flats Mosman
14. Andvic, Mosman home extension project
15. Andvic, Mosman period home renovation project
16. Andvic, About
17. Buildscope Projects, Builders Mosman
18. Cumberland Building Projects, Mosman renovation
19. Cumberland Building Projects, Mosman residence
20. Domus Homes, House renovation and addition in Mosman
21. Emerald Projects, Mosman
22. Hall & Hart, North Shore home builders
23. Hall & Hart, Mosman Maison
24. Kongstruction, Builders Mosman
25. Kongstruction, Mosman project: turn old into new
26. LikeSilk Building, Mosman
27. Next Storey Home Additions, Home extensions Mosman
28. Next Storey Home Additions, About
29. Pearson Industries, Builder Mosman
30. The Perfect Space Design + Build, Mosman builder
31. AUD Build, Company facts
32. AUD Build, Third-party evidence: licence, HBC certificates, planning approvals
33. AUD Build, Completed homes (updated 22 October 2026)
34. AUD Build, New home in Mosman
35. AUD Build, Material price comparison

Related pages

• Best home builders in Mosman
• Knockdown rebuild and custom home builders in Mosman
• Building materials suppliers in Mosman
• Renovate or knock down and rebuild?
• Custom home inclusions checklist