Running out of room doesn’t always mean moving. If you love your street, your school zone and your block, a second storey extension lets you build up instead of out. It’s also one of the more complex projects a home can go through. Here are the eight things to settle before you commit to a second storey extension in Brisbane.

1. Can Your Existing Home Support a Second Storey?

Everything starts with the structure. A builder and structural engineer need to check:

  • Foundations and footings, and whether they can carry the extra load
  • Wall framing and bearing walls
  • Slab or stumps, depending on the home’s construction
  • Soil conditions, which vary a lot across Brisbane suburbs

Some homes need strengthening before anything goes on top. That’s normal, but it needs to be in your plan and budget from day one.

2. Council and Building Approvals

Most second storey additions in Brisbane need approval. Height limits, setbacks, site coverage, overlays (flood, character, bushfire, and others) and neighbour impacts can all affect what you’re allowed to build. An experienced builder handles this process with you, so the design is approvable before you spend money on detailed documentation.

3. Your Budget: What Drives Second Storey Extension Cost

Your second storey extension cost depends on several factors:

  • Size and number of new rooms
  • Structural upgrades to the existing home
  • Number of bathrooms and kitchens (wet areas cost more)
  • Stairs, and how they fit into the existing layout
  • Roof changes
  • Finishes and fixtures
  • Demolition and site access

Get a realistic estimate before you talk to a builder. A free-to-start tool like the B4U Build cost calculator lets you choose “Home Extension,” add your site details and rooms, and see an itemised estimate in about three minutes, with no plans needed. You can then download the cost report and builder brief to share with designers and builders. Then ask for a detailed, itemised quote rather than a single lump sum. It makes comparing builders far easier and avoids surprises mid-build. You can see how RedKem approaches this on our pricing page.

4. Living Through the Build

Can you stay in the house? Often yes, but expect noise, dust and some loss of access. For larger works some families rent short-term. A good builder will:

  • Stage the work to limit disruption
  • Protect the existing living areas
  • Give you a clear timeline and regular updates

5. Stair Placement and Floor Plan Flow

Where the stairs go affects both floors. Poor placement eats into living space downstairs and makes the upper level feel disconnected. Thoughtful design links the two levels so the extension feels like part of the original home, not a box added on top.

6. Matching the Look of Your Existing Home

A second storey changes your home’s street presence. Roof lines, materials, window proportions and colours all need to work together. Done well, the result looks like it was always meant to be there. This is also where council character overlays can come into play.

7. Comfort, Light and Energy Efficiency

Building up is a chance to improve how your home performs:

  • Orientation and window placement for light and breezes
  • Insulation in the new roof and walls
  • Ventilation to handle Brisbane’s heat and humidity
  • Possible upgrades to the existing ground floor while the builder is on site

8. Choosing the Right Builder

Second storey additions are a specialist job. Look for:

  • A current QBCC licence
  • Proven second storey experience you can see, not just hear about
  • Clear contracts, transparent pricing and a defined process
  • Good communication throughout the build

RedKem gives clients 24/7 online access to their project, so you can follow progress without chasing for updates.

See What a Second Storey Addition Looks Like

Seeing finished work is the easiest way to picture your own project. Have a look at these RedKem builds:

You can browse more on our Second Story Additions page.

Is a Second Storey Right for You?

If you want more space without leaving your suburb, building up is often the smartest option. The key is getting the early decisions right: structure, approvals, budget and design. Thinking about a second storey extension in Brisbane? Call RedKem Constructions on 1300 002 102 to talk through your plans.

Frequently Asked Questions.

The cost depends on the size of the addition, the structural work your existing home needs, the number of wet areas (bathrooms, kitchens), the stairs, the roof changes and your finishes. Use a calculator like B4U Build for a quick estimate, then ask builders for an itemised quote. You can see how RedKem prices projects on our pricing page.

In most cases, yes. A second storey addition usually needs building approval, and sometimes council development approval. Height limits, setbacks and overlays (such as flood or character) can all affect your design. Your builder or certifier can confirm what applies to your property.

It depends on your foundations, framing and soil conditions. A structural engineer should assess the home before design begins. Some houses can take the extra load as they are, and others need strengthening first.

Many families do, especially when the builder stages the work and protects the existing living areas. Expect some noise, dust and limited access at times. For larger projects, some families choose to rent short-term.

Timelines vary with the size of the project, approvals and weather. Your builder should give you a clear schedule at the start and keep you updated through the build. RedKem clients also get 24/7 online access to their project.