Second Storey Additions · Castle Hill
Add bedrooms, bathrooms & living space, without moving.
Fixed price second storey additions for Castle Hill homeowners, from $274,000. Built to our Above Standard Carpentry Specification, with a solid Hebel PowerFloor included as standard on early projects.
Hebel PowerFloor included free on early Castle Hill packages. A solid, quieter floor, normally an upgrade.
Space without moving
More room, without leaving Castle Hill.
You love your Castle Hill street, your neighbours, the school run. What you do not love is running out of space. Moving means stamp duty, agent fees and starting over somewhere that may never feel like home.
On a million dollar purchase, stamp duty alone runs to roughly $40,000 before you have paid an agent, a conveyancer or a removalist. In a suburb like Castle Hill, with the schools families move here for and the Metro into the city, that maths rarely favours moving.
A second storey addition lets you stay exactly where you are and build the space you need. Extra bedrooms, a second bathroom, a private master retreat or an upstairs living zone, without giving up a metre of backyard.
Strava Group builds second storey additions across Castle Hill and the wider Hills District. About us.
Choose your package
Three fixed price starting points.
All prices are “from”, GST inclusive, and apply to the new upper floor works only. Every package includes Hebel PowerFloor while the current offer runs.
- New upper level with 1 bedroom
- 1 bathroom or ensuite
- Retreat or study zone
- Internal staircase allowance
- Hebel PowerFloor included
- 2 to 3 bedrooms upstairs
- 1 family bathroom
- Internal staircase
- Moves bedrooms up, opens your ground floor
- Hebel PowerFloor included
- 3 bedrooms upstairs
- 1 bathroom
- Upstairs retreat or living area
- Internal staircase
- Hebel PowerFloor included
Not a package job?
Custom second storey additions.
The three packages cover the shapes we build most often. Plenty of Castle Hill homes do not fit them. Wider footprints, a second bathroom upstairs, a full ground floor reconfiguration underneath, or a split level that has to be worked with rather than against.
We build those too, priced against your plans rather than squeezed into a package. Same fixed price contract, same standards, same specification. Custom builds generally run $270,000 to $400,000 depending on size and what we find underneath.
- Any size or configuration
- Ground floor works included in scope
- Heritage and character homes
- Structural upgrades where needed
Every plan is drawn to suit your Castle Hill home. Package price covers the new upper floor works. Design, engineering and council approvals are quoted separately as preliminaries, at roughly $30,000.
The Strava difference
A solid, quieter upstairs.
Most second storey additions sit on 19mm lightweight particleboard. While it does the job, it can feel hollow and bouncy underfoot. As a result, footsteps carry straight down to the rooms below.
For early Strava Group projects in Castle Hill we include Hebel PowerFloor as standard. It is a 75mm autoclaved aerated concrete panel, almost four times thicker than standard flooring. Laid over your joists, it creates a solid, concrete style floor.
- 75mmAlmost 4 times thicker than standard 19mm particleboard, so it feels solid underfoot with no bounce or flex.
- 0Squeak free. The thick AAC panel does not creak the way timber based flooring can over time.
- ↓Helps reduce noise transfer between levels for a quieter upstairs, especially with the right ceiling system.
- ✦Non combustible AAC, with thermal insulation and moisture resistance built in.
Local knowledge
Building a second storey in Castle Hill.
Castle Hill is one of the easiest suburbs in Sydney to add a second storey to. Here is what shapes a project locally.
The Hills Shire
Castle Hill sits within The Hills Shire Council. The planning controls here are among the more generous in Sydney, and for a typical Castle Hill block a well designed second storey usually fits inside them with room to spare.
CDC is usually available
Castle Hill has no significant heritage overlays, so the fast Complying Development pathway is open for most homes. A private certifier can approve the project rather than a full council DA, which takes months off the timeline. We confirm which pathway applies to your block before quoting.
80s and 90s brick veneer
Much of Castle Hill was built in the 80s and 90s: brick veneer on concrete slabs, trussed roofs, generous footprints. It is some of the most straightforward housing stock in Sydney to build a second storey onto, once the slab and footings are confirmed.
Big, with real access
Castle Hill blocks commonly run 700 square metres and up, with double driveways and side access. Crane and scaffold access is rarely a problem here, and that flows straight through to cost.
Slopes and clay
Parts of Castle Hill fall away sharply, and the shale and clay soils through the Hills move with the weather. Both affect the footings more than the design, and both are exactly what the engineer’s assessment is for.
Two storeys are the norm
Whole Castle Hill estates were built double storey from day one. A well designed addition does not just fit the street here, it brings a single storey home up to what the street already is.
Before anything is designed
Can your house actually take a second storey?
This is the first question, and it usually gets skipped in favour of talking about floor plans. It is worth answering properly, because for roughly one house in six the answer is no, or not without spending money you would rather put into the addition itself.
What is under the house
Your house was built to hold up one storey. A second floor roughly doubles what the foundations carry. Most Castle Hill homes sit on concrete slabs, which are usually a strong starting point, but the clay soils through the Hills mean the engineer still checks before a design is drawn. That is a real cost, and you want to know about it before you fall in love with a floor plan.
What the walls are made of
A double brick house, a brick veneer house and a timber framed house each handle a new floor differently. The question is whether the weight can travel down through the walls you already have, or whether new supports need to appear somewhere you would rather they did not.
What the timber has been through
Framing that looked fine when you bought the place can be quietly damaged in ways that only matter once you ask it to hold a floor up. We look before we quote, not after.
What your council allows
City of Parramatta sets a height limit and protects your neighbours’ winter sunlight. Between them, those two rules often decide your ceiling heights and your roof shape before anyone draws anything.
Whether we can get a crane in
Access is rarely the problem in Castle Hill. Where cost does creep in is steep blocks and retaining, which we price at the start rather than discover in week three. Better to know at the start than in week three.
How we find out
An engineer checks the first three. We organise that before we give you a fixed price, because a price without it is a guess.
Clear scope
What is included, and what is not.
Being upfront about both is exactly how we keep your fixed price genuinely fixed.
Included as standard
- Hebel PowerFloor (75mm solid AAC panel), where suitable
- Structural timber framing to engineer’s details
- Wall framing and roof framing
- Roofing
- External cladding
- Aluminium windows
- Insulation
- Plasterboard and setting
- Internal doors, hardware and hinges
- Skirting and architraves
- Standard staircase allowance
- Electrical allowance, LED downlights and smoke alarms
- Bathroom allowance (where part of the package)
- Painting to new upper floor areas
- Builder supervision and construction management
Quoted separately if needed
- Structural steel beams (unless listed)
- Footing, pier or foundation upgrades
- Additional bracing to the existing house
- Ground floor renovations or layout changes
- New downstairs kitchens, bathrooms or laundries
- Existing termite, rot, water or defect repairs
- Electrical mains, switchboard or stormwater upgrades
- Air conditioning upgrades
- Design, engineering, BASIX and council approvals (preliminaries)
- Rock excavation or unforeseen ground conditions
- Premium window, cladding or staircase upgrades
- Any works outside the new upper floor package area
Want the full detail?
The complete inclusions and exclusions, right down to hardware, fixtures, fittings, finishes and specifications, are provided in detail when you enquire, and confirmed in your contract.
Our fixed price packages apply to the standard new upper floor works listed above. If your property needs structural steel, footing upgrades, extra bracing, service upgrades, defect repairs or downstairs renovation works, those items are assessed and quoted separately, clearly, before you commit. Where something genuinely cannot be priced until the roof comes off, it is listed as a provisional sum with a stated allowance rather than hidden inside the total.
The first decision
Up or out?
Most people arrive having already decided. In Castle Hill the block gives you a real choice, and plenty of homeowners here genuinely could go either way.
Go up
Go up if the yard, the pool or the future granny flat matters to you. Castle Hill blocks are big, and a second storey keeps every metre of them while adding the bedrooms upstairs.
It costs more per square metre than extending out, but it leaves the garden and the side access intact, and two storey homes are already the norm in most Castle Hill streets.
Extend out
Extending out is a genuine option on a Castle Hill block. Many homes here can give up yard and still keep more than an inner west house started with.
Ground floor work is cheaper per square metre, you can often stay living there, and it avoids the structural question entirely. A rear home extension in Castle Hill can be the better value answer.
If the existing house needs work regardless, a full renovation staged alongside the addition costs less than doing them five years apart, because you pay the preliminaries once and open the walls once.
Plan · Manage · Build
Your Castle Hill second storey, step by step.
Our proven building process is designed to customise your project, avoid cost traps and deliver your vision with minimum disruption.
Your Initial Assessment
First, we review your enquiry, site, timeframe and budget. Then we contact you within 24 to 48 business hours to arrange a consultation.
Consultation & Build Cost Estimate
An experienced builder discusses your project and site, then prepares a detailed build cost estimate.
Preliminary Agreement
This formalises your engagement, secures your spot in our schedule and starts coordination with consultants and authorities.
Plans & Design
Next, we coordinate design and documentation. As a result, you get plans that suit your brief, site and budget, with optional 3D modelling.
Submission to Council
After that, we prepare and lodge your DA and CC, or a CDC with The Hills Shire. Approval typically takes around 4 to 8 weeks.
Final Cost & Contract
Once approved, we confirm the final build cost and issue your HIA Fixed Price Building Contract. Importantly, you review it in full before signing.
Pre-Start Selections
Together, we finalise your fixtures, fittings and finishes with suppliers, so everything is confirmed before work begins.
Start of Construction
Your project manager meets you on site to confirm documentation, expectations and communication before works commence.
Construction
Your project manager oversees the build, coordinates trades and manages quality, keeping disruption to a minimum.
Practical Completion
A final inspection, then warranties and compliance documents are provided. We stay available after handover.
Why Strava Group
A licensed builder who knows what is behind the wall.
A stronger standard inclusion
Hebel PowerFloor comes standard on early packages, giving a solid, quieter upstairs that standard lightweight flooring cannot match.
Structure first, always
Over a decade across site and project management on residential and commercial builds, backed by a trade background. Your addition is framed and supported to our internal Above Standard Carpentry Specification, so the new level feels solid, aligned and original.
Clear scope and fixed pricing
Transparent inclusions and exclusions from day one, so you know exactly what your Castle Hill project covers before you commit. NSW Builder’s Licence 487370C.
Also exploring other options? Strava Group builds home renovations and home extensions in Castle Hill. See our recent work in the gallery.
Nearby
Also building across the Hills District.
Second storey additions nearby
Other services in Castle Hill
See all Sydney service areas.
Get in touch
Talk to a builder about your Castle Hill home.
Tell us about your home and what you would like upstairs. We will let you know whether your property suits a second storey and which package fits. No cost, no obligation.
Good to know
Frequently asked questions.
How much does a second storey addition cost in Castle Hill?
Do I need council approval for a second storey addition in Castle Hill?
Can you add a second storey to an 80s or 90s brick home in Castle Hill?
Can my Castle Hill house support a second storey?
What is Hebel PowerFloor and why is it included?
Will I have to move out during construction?
How long does a second storey addition take?
Does a second storey addition add value to an Castle Hill home?
What is not included in the package price?
Are you licensed and insured?
Get your free quote today.
Ready to build up in Castle Hill?
Contact Strava Group for a free consultation and a quote for your second storey addition, with Hebel PowerFloor included while the offer runs and a fixed price scope you can rely on. Building up is one of the most cost effective ways to add space and value under current NSW housing and construction settings.
