Renovating your home is a big decision, and most people want clear, room-by-room renovation cost guidance before they even call a builder. This guide breaks down what you can realistically expect to spend on kitchens, bathrooms, and extensions, in plain language you can actually use for planning.
You’ll see a simple, detailed residential cost breakdown for each space, plus tips on setting a renovation budget per room that fits your goals and avoids surprises. Think of this as your residential renovation cost guide so you can better understand the cost to renovate each room before signing any quote.
How Renovation Estimates Are Built (Before You Look at Each Room)
Before you look at costs for each room, it helps to know how builders calculate renovation costs. Most prices come from a clear scope, a materials and labour breakdown, and the level of detail in your quote. Understanding this detailed residential cost breakdown makes it easier to trust what’s in a renovation quote.
- Scope of Work: Builders start with a clear scope of work definition for each room—what’s being kept, moved, or replaced.
- Materials vs Labour: A good quote shows a basic materials and labour breakdown, not just one lump sum.
- Detailed vs Ballpark Quotes: A quick “ballpark” is only a rough guide; a detailed quote explains what to expect in a renovation quote line by line.
- Why Quotes Differ: Two builders may price the same room differently based on allowances, labour rates, and how they price kitchens and bathrooms.
- Assumptions and Exclusions: Look for notes on what’s excluded so your detailed residential cost breakdown doesn’t hide surprises.
- Ask, Don’t Guess: Always ask the estimator to explain your renovation quote in simple terms if something isn’t clear.
Kitchen Estimates – From Budget Refresh to Full Rebuild
Kitchen costs can swing a lot, from a simple facelift to a full new space. Before you panic at the numbers, it helps to see where the money actually goes and how scope changes things. This section explains the room-by-room renovation cost for kitchens in plain, honest language.
You’ll see average cost to renovate a kitchen across different sizes, what pushes prices up, and how your choices around layout, cabinetry, and services shape your renovation budget per room. By the end, you’ll know whether you’re closer to a light refresh or a true full kitchen remodel.
Typical Kitchen Cost Ranges
Most kitchen renovation costs fall into clear bands based on size and scope. A small kitchen with a simple layout and basic finishes will usually sit at the lower end, while a large kitchen with new layout, upgraded appliances, and custom joinery moves quickly toward a full kitchen remodel price.
If you keep your existing layout and services, your room-by-room renovation cost stays more controlled. As soon as you start moving walls, sinks, or ovens, you’re paying for extra trades, design time, and planning. This is where renovation budget planning really matters—knowing your range before you start saves stress later.
Main Cost Drivers – Cabinetry, Benchtops, Services
The biggest driver in kitchen pricing is usually cabinetry. Flat-pack units help keep costs down, while custom cabinets with soft-close hardware and clever storage quickly lift the total. Benchtops are next: laminate is budget-friendly, while stone or engineered surfaces come at a higher kitchen cabinetry and benchtop pricing point.
Services are the quiet costs people forget. Plumbing and electrical rough-in costs go up when you add an island, relocate the sink, or move the cooktop. When you look at a detailed residential cost breakdown, you’ll often see that materials and trades together make up most of the total, with design and project management filling the rest.
Cosmetic vs Full Gut Kitchen Renovations
A cosmetic kitchen upgrade keeps the bones of the room. You might swap doors, benchtops, handles, and paint without touching the layout or services. This keeps cosmetic kitchen upgrade cost moderate and disruption low, and it can still make a tired space feel fresh and usable.
A full gut renovation is more serious. Cabinets come out, the layout changes, and walls may be removed or opened up, bringing in demolition and disposal costs and potential structural changes and framing costs. This is where the cost difference between cosmetic and full gut renos becomes obvious—and where hidden costs in home renovations show up if issues are found behind the old finishes.
Worked Example – $35k vs $65k Kitchen
Seeing numbers in context helps make sense of your kitchen renovation costs. A basic kitchen around $35k might use flat-pack cabinets, a simple benchtop, and standard appliances, while a higher-spec $65k kitchen leans on custom joinery, stone tops, and premium fittings. Both can work; they just serve different needs and budgets.
Below is a simple way to think about a sample kitchen renovation breakdown:
- Cabinetry & Joinery: Often the largest share in both $35k and $65k kitchens; custom designs push the higher budget up quickly.
- Benchtops & Splashbacks: Laminate and basic tiles suit the lower budget; stone and feature splashbacks sit in the higher range.
- Appliances & Fixtures: Standard packages fit the $35k example; upgraded brands and extras (wine fridge, built-in coffee) sit in the $65k range.
- Trades (Plumbing & Electrical): More relocation and new points mean more cost, especially in the higher-priced kitchen.
- Contingency & Finishing: A small buffer in each example covers minor surprises and keeps your renovation budget per room realistic.
This kind of detailed residential cost breakdown shows you what to expect in a renovation quote and where changing one choice can move the final kitchen number.
Bathroom Estimates – Tiling, Waterproofing, and Fixtures
Bathrooms are small spaces with big price tags. A simple change of fixtures is very different from a full rebuild with new tiling and waterproofing. Knowing what sits behind a bathroom renovation estimate helps you set a real renovation budget per room and avoid nasty surprises once the tiles come off.
This section breaks down bathroom renovation costs by size and type, then explains the technical work—tiling, waterproofing, and rough-ins—that makes up a large part of your room-by-room renovation cost. You’ll also see how a light refresh compares to a full back-to-studs job, with a clear money example at the end.
Bathroom Cost Ranges by Size and Type
Not all bathrooms cost the same. A compact guest toilet, a busy family bathroom, and a private ensuite each sit in different cost bands. A small bathroom with basic finishes will sit at the lower end, while a family bathroom or ensuite with more fixtures will usually cost more to renovate.
Your bathroom renovation estimate also changes with layout. If you keep the same positions for the shower, toilet, and vanity, the room-by-room renovation cost stays more controlled. As soon as you start turning a standard bathroom into a wet room or move fixtures around, your renovation budget per room needs to grow to cover extra labour and materials.
Waterproofing, Tiling, and Rough-Ins
Behind every good bathroom lies careful waterproofing and tiling. Bathroom tiling and waterproofing costs are often charged per square metre and form a big share of the total. The more wall and floor area you tile, the more you pay in both materials and tiler labour. Feature walls and niche shelves also add to the bill.
Plumbing and electrical are the other heavy hitters. Plumbing and electrical rough-in costs rise when you relocate the shower, change the bath type, or add heated towel rails and extra lights. Good waterproofing requirements are not just “nice to have”—they’re important for compliance, insurance, and avoiding leaks. When you see a detailed residential cost breakdown, these technical items explain a lot of the total figure.
Cosmetic vs Full Bathroom Renovations
A cosmetic bathroom facelift keeps things simple. You might swap the tapware, vanity, shower screen, and mirror, and maybe regrout the tiles. This keeps bathroom facelift cost in a more friendly range and can be enough if the layout works and the waterproofing is still in good shape.
A full bathroom strip-out is more involved. Tiles come off, walls may be opened, floors are adjusted for proper falls, and new waterproofing, plumbing, and tiling go in. This “back-to-studs” approach carries higher bathroom renovation costs, more mess, and a bigger risk of hidden costs in home renovations if old issues appear. It also calls for bigger cost contingencies and overruns in your renovation budget per room.
Worked Example – $20k vs $40k Bathroom
It’s easier to read a bathroom renovation estimate when you see how the money splits. A simple bathroom around $20k might reuse the layout with mid-range tiles and fittings. A higher-end $40k bathroom could include more tiling, custom joinery, and upgraded fixtures, pushing both materials and labour breakdown higher.
Here’s a simple way to think about a sample bathroom quote:
- Demolition & Disposal: Old tiles, fixtures, and rubbish removal take a small share in both $20k and $40k jobs, but costs rise if asbestos or tricky access appears.
- Waterproofing & Tiling: In the $40k bathroom, more surface area, premium tiles, and detailed work push bathroom tiling and waterproofing costs well above the basic option.
- Plumbing & Electrical: Moving the shower or adding extra lighting lifts plumbing and electrical rough-in costs, especially in the higher-priced bathroom.
- Fixtures & Joinery: Standard fittings suit the $20k example, while custom vanity units and premium tapware fill much more of the $40k budget.
- Contingency: Both should include a small buffer so your renovation budget per room can handle minor surprises without breaking your plan.
Extension Estimates – Extra Space, Extra Structure
Extensions feel exciting because you’re gaining more space, but they also come with serious structure and cost. This part of the home extension cost guide explains how builders think about square-metre cost for an extension, and why adding rooms can change both your budget and your room-by-room renovation cost.
Single-Storey Extension Estimates
A ground-floor or single-storey extension estimate usually starts with a price per square metre. From there, costs change based on how simple or complex it is to tie the new structure into your existing house. A basic rear living area is often cheaper than adding a fully finished bedroom with built-ins or a utility room with extra services.
Your home extension costs also depend on structural work—footings, framing, and how much roof and wall work is needed. A simple box off the back with basic finishes will sit at the lower end of the ground floor extension cost, while detailed designs with large windows, doors, and custom finishes will push the number higher.
Two-Storey Extension Pricing
When you build up instead of out, your two-storey extension pricing reflects more structure. Extra beams, steel, and bracing are often needed to support the new level, and you’ll usually add a staircase too. This extra framing and engineering quickly increases the cost of structural changes for extensions compared to a single-storey build.
There’s also more impact on the roof and services. Extending plumbing and electrical to the upper level, changing the roof line, and adding insulation all feed into the final square-metre cost for extension. For some homes, going up makes sense when land is tight, but it almost always costs more per metre than keeping everything on the ground.
Extensions That Include New Kitchens or Bathrooms
Not all extensions are just extra living space. When you add a new kitchen or bathroom into an extension, you’re combining home extension costs with the complexity of kitchen renovation costs or bathroom renovation costs. That means more services, waterproofing, and joinery, which can multiply your room-by-room renovation cost.
A simple living or dining extension mainly involves structure, windows, doors, and basic finishes. As soon as you include a full kitchen or an ensuite, you add plumbing, electrical upgrades, tiling, and fixtures. This is where a detailed residential cost breakdown becomes important so you can see how much of the total is the extension shell and how much is the new wet area.
Worked Example – 25m² vs 45m² Extension
To make extension costs easier to picture, it helps to compare two simple scenarios: a smaller living-room extension and a larger extension that also includes a bedroom and ensuite. The size is different, but it’s really the complexity and extra services that move the budget the most.
- 25m² Living Extension (Simple Shell)
Think of this as a basic new living room. Most of the budget goes into walls, roof, basic flooring, and tying the new space into the existing house. Services are usually limited and simple. - 45m² Extension with Bedroom + Ensuite
This option adds more structure and floor area plus a full new bathroom. You’re paying for extra framing, more finishes, and all the plumbing, tiling, and fixtures that come with an ensuite. - Shared Structure & Roof Work
Both extensions need footings, framing, and roof adjustments. The larger one simply needs more materials and labour, which pushes up total home extension costs. - Rising Cost per Square Metre with Complexity
The square-metre cost for extension often increases as you add bathrooms or extra services. It’s not just about size; complexity and wet areas drive the rate higher. - Sample Extension Quote Breakdown
A sample extension quote is usually split into structure, roof, services, finishes, and contingency. In the 25m² option, more of the budget sits in the shell; in the 45m² option, more is taken by services and bathroom finishes. - Contingency and Risk Buffer
The larger, more complex extension should include a bigger allowance for cost contingencies and overruns, because there are more trades on site and more chances for small variations to add up.
Hidden Costs and Line Items Owners Often Miss
Even with a solid quote, there are costs that don’t show up clearly until work starts. These hidden costs in home renovations can push your budget if you haven’t allowed for them. Understanding them early helps you read a detailed residential cost breakdown with much more confidence.
- Demolition, Disposal & Site Conditions
Before anything new goes in, the old needs to come out. Demolition and disposal costs for old kitchens, bathrooms, tiles, and walls can add a lot, especially if you need skip bins, tipping fees, or extra labour. If asbestos is found, access is tight, floors are uneven, or parking is limited, you may also see more cost contingencies and overruns added to your bill. - Approvals, Permits & Professional Fees
Structural changes and extensions often need building approvals and permits before work can begin. On top of that, you may pay for engineering, design, certifier, or surveyor services. These don’t always sit inside the “build” line, but they are part of your real spend. Treat them as key items in your home extension cost guide, and make sure they’re clear in your renovation quote. - Allowances & Provisional Sums in Quotes
Many quotes include allowances for fixtures and fittings (PC items) for things like tiles, tapware, and appliances. If you pick items above the allowance, you pay the extra. Quotes may also include provisional sums for unknown soil, drainage, or rock. These are estimates only. To reduce provisional sum risk, ask your builder to explain these lines, tighten them where possible, and be sure you understand what to expect in a renovation quote before you sign.
Planning a Realistic Room-by-Room Renovation Budget
A renovation feels less scary when you break it into clear pieces. Instead of guessing one big number, you set a renovation budget per room for the kitchen, bathroom, and any extensions, then add a buffer. This way your room-by-room renovation cost actually matches what you can afford.
This section helps you turn rough price ranges into a simple plan, protect yourself from surprises, and talk to builders with more confidence. Used well, it becomes your own detailed residential cost breakdown before any quote lands in your inbox.
Setting Budgets for Kitchens, Bathrooms, and Extensions
Start by deciding how much you’re willing to spend on each major area. Using room-by-room cost estimates as a guide, you can split your total into kitchen, bathroom, and extension bands instead of letting one space swallow the whole project.
- Simple Budget Bands per Room
Use broad brackets for each space (for example: kitchen, bathroom, extension) based on the level of finish you want. This turns vague ideas into a clear renovation budget per room you can share with builders. - Prioritise the Rooms That Matter Most
Think about how you live. A tired main bathroom or busy family kitchen often deserves more of the budget than a spare room. This helps you allocate renovation funds per room in a way that matches real daily use and value.
Contingencies, Overruns, and Timeline Staging
Even with careful planning, there are always a few unknowns. That’s why you build in cost contingencies and overruns on top of your base numbers to protect against hidden costs in home renovations.
- Build in a Safety Buffer
Adding around 10–15% to each room’s budget gives you room to handle small surprises without panic. This buffer sits alongside your main figures and is part of a realistic renovation budget per room. - Plan Your Staging and Timeline
Decide if you’ll renovate one room at a time or tackle everything in one go. A clear renovation timeline and staging plan helps you line up your budget with your cash flow and how long you can live through disruption.
Worked Example – Simple Room-by-Room Budget Plan
A quick example can make things much clearer. Imagine you set a total cap for your project, then divide it between the kitchen, bathroom, and an extension, with a small buffer for each. This becomes your sample renovation budget and keeps the whole plan anchored.
- Kitchen Budget + Buffer
Set a base figure for the kitchen, then add a 10–15% contingency. This protects you if cabinetry, benchtops, or services come in a bit higher than expected. - Bathroom Budget + Buffer
Do the same for the bathroom. Because waterproofing and tiling can uncover issues, a strong buffer here is key to a calm room-by-room renovation cost plan. - Extension Budget + Buffer
For extensions, allow for structure, roof, and services, then add contingency for unknowns in the ground or framing. When you add all three rooms together, the total must still sit under your overall cap. If not, you adjust on paper first, not mid-build.
Comparing Quotes and Working With Builders/Estimators
Once you have a rough plan, you’re ready to collect and compare quotes. The goal is to compare like with like so you don’t pick a “cheap” option that’s missing key items.
- Compare Scope, Inclusions, and Allowances
Check that each quote covers the same rooms, finishes, and fixtures. Ask for a simple materials and labour breakdown so you know what you’re paying for and can fairly compare builder quotes. - Key Questions to Ask Your Builder or Estimator
Ask how they price kitchens and bathrooms, what might change the number, and how allowances and provisional sums work. Clear answers show you what to expect in a renovation quote and make it easier to choose someone you trust, not just the lowest number.
Room-by-Room Cost Ranges
| Room | Typical Scope | Approx. Cost Range | Budget Tip |
| Kitchen | Cosmetic → Full rebuild | $20,000 – $70,000+ | Layout changes, cabinetry and benchtops move cost the most. |
| Bathroom | Cosmetic → Back-to-studs | $15,000 – $40,000+ | Waterproofing and tiling take a big share of the budget. |
| Extension | Single or two-storey shell | $60,000 – $250,000+ | Size, structure, and whether you add a kitchen/bathroom are key drivers. |
FAQs
For most homes, an average kitchen reno will sit somewhere between a basic refresh and a full rebuild. A realistic average kitchen reno cost is usually in the tens of thousands, with bathrooms often a little less but still substantial. Your final figure depends on size, finishes, and how much layout and services change.
Reconfiguring inside your existing walls is usually cheaper than building out or up. A full extension adds structure, roof, and services, which lifts home extension costs. However, if your floor plan is very tight, an extension may offer better long-term value than forcing a poor layout to work.
A good rule of thumb is to allow around 10–15% on top of your planned room-by-room renovation cost for hidden costs in home renovations. This buffer covers things like minor structural fixes, extra labour, and small variations so your budget can absorb surprises without breaking.
The easiest check is to compare your wish list against rough room-by-room cost estimates. If you want high-end finishes in both the kitchen and bathroom plus an extension, but your total is closer to a basic renovation budget, something has to give—either scope, finish level, or number of rooms.
Yes, many people do. You might start with the kitchen, then the bathroom, then look at an extension later. A staged approach works well if you plan a clear renovation budget per room in advance and make sure each stage fits into the bigger picture, not as a standalone one-off job.
Conclusion – What to Expect and How to Move Forward
Renovating room by room is much easier when you understand the main cost drivers for kitchens, bathrooms, and extensions. Scope, finishes, services, and structure all shape your room-by-room renovation cost, which is why a clear renovation budget per room and simple scope are so important.
A detailed residential cost estimate breakdown and transparent quote will always beat a vague ballpark. Before you sign anything, compare renovation quotes side by side, ask about allowances, and check how contingencies are handled. That’s what to expect in a renovation quote and the smartest way of planning your renovation costs with fewer surprises.
