Adding a second storey vs building out
Need more room in a home you love? How going up with a second storey compares with extending out across the block, on structure, approvals, yard and disruption.
When a home you love starts to feel tight, there are two ways to find more space: build up with a second storey, or build out across the ground. Both are proven ways to grow a home in SA and Victoria, and the right one depends far more on your block, your existing structure and how you want to live than on a simple preference. Going up protects your yard but leans on the existing structure and approvals. Going out is often simpler to build but eats into your land. Here is how to weigh it.
| Second storey | Build out | |
|---|---|---|
| Yard impact | Keeps your garden and outdoor space | Uses up part of the block and setbacks |
| Structure | Existing footings and walls must carry the new load | New footings, but the old home is largely untouched |
| Best for | Smaller blocks where land is precious | Larger blocks with room to spread |
| Disruption | Roof off, often move out for a stretch | Often possible to stay in part of the home |
| Approvals | Overlooking and overshadowing rules apply to the upper level | Setback and site-coverage rules apply at ground |
| Views and breeze | Upper level can catch a view or breeze | Stays at ground level |
Start with the block, and the bones
The block usually makes the first call. If you have generous land and room within the setbacks, building out is often the simpler, lower-risk path because it leaves the existing home largely alone. If the block is small or already close to full, going up is frequently the only way to add real space without losing the yard. For a second storey there is a second question that matters just as much: whether the existing footings and walls can carry the new load, which needs a structural engineer to confirm before you get too attached to the idea.
Approvals pull in different directions
The two paths trip over different rules. A build-out is governed by setbacks and site-coverage limits at ground level, so the question is how close to the boundaries and how much of the block you can cover. A second storey brings overlooking and overshadowing into play, because an upper level can see into neighbours yards and cast shade, and councils in both SA and Victoria watch that closely. Check the controls and any overlays on your property early, because they can quietly rule one option in or out.
Think about how you will live, and the disruption
Going up gives you a natural split between living downstairs and sleeping upstairs, and a chance at a view or a breeze, but it adds a staircase and usually means moving out for a stretch while the roof comes off. Building out keeps everything on one level, which is easier for young kids and ageing in place, and you can sometimes stay living in part of the home through the works. Weigh the lifestyle you want against the disruption you can stomach.
Second storey
- Keeps your yard and garden intact
- Suits smaller or tightly held blocks
- Upper level can capture a view or a breeze
- Clear separation of living and sleeping zones
- Existing footings and walls must be checked to carry the load
- A staircase takes floor space from the level below
- Usually means moving out while the roof is off
- Upper-level overlooking and overshadowing rules are stricter
Build out
- Often simpler to build with less structural risk
- The existing home is largely left intact
- No staircase to fit in
- You can sometimes stay living in part of the home
- Uses up yard and outdoor space
- Limited by setbacks and site coverage rules
- Less suited to small or already-full blocks
- Keeps everything on one level with less zoning
Build out when you have the land and want a simpler, lower-risk job that leaves the existing home mostly alone. Go up with a second storey when the block is tight, you want to protect the yard, or you are after a view and a clear split between living and sleeping. Get a structural engineer and your council overlays involved early, because they often decide this before your wish list does.
Still weighing it up?
Tell us about your block and what you want, and we will match you with three builders across SA or Victoria who do this sort of work well.
Match me with 3 buildersCommon questions
Is it cheaper to build up or out?
Each has a different mix of work: building out needs new footings and roofing but leaves the existing home alone, while going up relies on the existing structure carrying the load and usually means moving out. The better value depends on your block, your structure and your design, so get both properly assessed.
Can my house support a second storey?
Not automatically. The existing footings and walls must be able to carry the extra load, so a structural engineer needs to assess the home before you commit. Some homes need strengthening first, which is a key part of deciding between going up and building out.
What approvals do I need to add a second storey?
Upper levels bring overlooking and overshadowing rules into play, because they can see into neighbours yards and cast shade. Councils in SA and Victoria assess these closely, so check your planning controls and any overlays early in the process.
Will building out use up my backyard?
Yes, extending at ground level uses part of the block and is limited by setbacks and site-coverage rules. If protecting your yard matters or the block is already tight, that is often the deciding factor that points you toward a second storey instead.