Second storey additions vs ground floor home extensions

Home renovators are often confused. Should they build a second storey addition or ground floor extension? In this blog, we’ll help you answer that question!
house extension
Image credit: Preston Lane via Dwell

Do you have a growing family and need more space at home, but you are hesitant to move because you’re in love with the place? If so, renovating your home is the next best thing. You can build outwards with a lovely house extension or build upwards with a first-floor addition. So, how do you know which project is the best for you? 

Here, you’ll read about the factors you need to consider when deciding between a ground-level house extension and a second-storey addition—plus the pros and cons of each one. You’ll also read about what to do in case you can do both on your property.  

house extension
Image credit: Addbuild Additions

A house extension vs a home addition

A home extension and addition can add real value to your home and give your family the extra square space you need. 

Why build a second storey addition?

If you’ve got limited land space and need to build more rooms, extending upwards is your best option. Adding another level to your house allows you to:

  • Build extra bedrooms for your children, extended family, and guests
  • Create a second living space and other rooms like a small library, home office, or a home theatre
  • Enjoy the view of the natural landscape or cityscape around you
house extension
Image credit: Aspect 11


  • You can instantly double your home’s floor space
  • You get to preserve your current outdoor space
  • You can enjoy lovely views
  • You can boost the resale price of your home


  • Not suitable for some house designs (i.e. heritage-listed homes)
  • Often requires you to change the layout of the ground floor
  • Sacrifices floor space to build stairs
  • It always requires structural rework
  • Daily activities get disrupted because the builders need to access your entire house during construction
house extension
Image credit: Ben Callery Architects

Why build a ground-level house extension?

If your block can accommodate an outward extension, then it’s a good option. A ground-level house extension makes these possible:

  • Additional room for lounging and entertaining
  • A more spacious, open plan living space
  • An indoor-outdoor space that you’ll love, and
  • A more accessible home for people with mobility issues
house extension
Image credit: Parsons Architects


  • It’s easier to build
  • It applies to most houses, provided that the plans meet the council requirements
  • It gives you bigger interior rooms
  • It gives you interior spaces that seamlessly blends with your landscaped backyard
  • It can boost the resale price of your home


  • The cost of laying a foundation is expensive
  • Often requires you to sacrifice a portion of your lawn and garden
house extension
Image credit: Urbane Design Architects

Which is cheaper? A second storey addition or a ground floor home extension?

The cost to renovate the house is the biggest concern of every homeowner. However, there is no general knowledge that proves one to be less expensive than the other. Each renovation project is unique and custom work. In some cases, a ground floor house extension is more expensive. Sometimes, it’s the first level addition that costs more depending on the level of renovation you want.

Apart from the final cost of the project, there are other factors to consider that we’ve listed below. Weigh them all, then decide which is the best way to move forward.

Other crucial factors to consider 

Your lot size and shape

The shape and size of your property are major considerations. 

You can do a ground floor extension and still enjoy a spacious backyard if you have a massive lot. Your outdoor spaces won’t feel cramped. 

If your lot is too small to accommodate a home extension, building up makes more sense. 

Your other plans with your outdoor space

Consider the other home improvement projects you want to do as well. Portion out the spaces for the features and structures you want (e.g. a lap pool, alfresco dining, granny flat, etc.) and how these will impact the look and feel of your backyard. 

house extension
Image credit: Modinex

The rooms and spaces you need

What is your ultimate goal you wanted to achieve with renovating your home?

Both an extension and addition makes sense if you want additional bedrooms and bathrooms. 

A ground-level extension makes more sense if you want recreational rooms such as a home theatre, rumpus room, playroom, home gyms, and family rooms. 

If you want an oversized kitchen and dining area, a ground-level extension is more suitable. 

If you want a more traditional setup, consider a first-floor addition, then put all the bedrooms upstairs. Let the upper floors be the province of bedrooms and other private areas (office, den, craft room, study, etc.). 

Planning and development regulations

Both home extensions and additions require council approval. So first, head to your local council’s website and review the planning and development regulations relevant to your project. Then, book a consultation with your local council’s planning and development team to discuss your pre-development application and to get initial feedback straight from the people who will assess your application! 

Image credit: Louvretec

Zoning regulations

Ask about the possible zoning issues during your pre-development application as well! 

Check the ordinances regarding: 

  • Setbacks – The limit of how close you could build next to your property’s boundary. Your local council will ask you to revise your plans to extend when it doesn’t meet the setback requirements. Your neighbour might lodge a complaint or an objection too.
  • Building height – The maximum height and the number of storeys a residential building is allowed in your community. Councils establish building height restrictions for a better street appeal. There are planned communities of single storey homes where homeowners are not allowed to build upward. Most councils with historic districts veto second-storey additions to preserve the architecture of heritage homes too.
Image credit: Barnes Coy Architects - Amagansett

Views and landscaping 

Another thing you should factor in is the view from your house. 

When you decide to build upward, you will capitalise on the incredible scenery around you, whether nature or the city skyline. A beautiful view from your home adds value to your property. 

Invest in a well-kept landscape when you decide to extend your ground floor and build an indoor-outdoor area. The best indoor-outdoor spaces integrate the two areas seamlessly and use the outdoors to beautify the home interiors. 


Home extensions and additions will disrupt your daily activities once construction starts, but ground floor extensions are often more convenient than second-floor additions. 

Picture this, in a ground floor extension, builders will only work on one side of the house. You can still establish a construction-free zone where you can stay. It is possible to live through the renovation.

In a second storey addition, the builders need to access the ground floor and remove the roof. Situations like this make it impossible for many families to live through the renovation. It might be wiser to move out until the renovation gets done.

Image credit: Modinex

Building a second floor on top of a ground floor extension

Building second storey additions and ground floor house extensions for many homeowners in the suburbs are realistic options.

This plan will be more expensive, but it will give you the best of both worlds. 

You will also need planning permission for this kind of renovation project. 

The best thing to do is work with skilled and qualified design and construction professionals in producing plans that will likely get approved.

Consider signing up to Superdraft to access the project coordination dashboard to find and engage these professionals. Then, use the dashboard to coordinate their work and manage your renovation like a pro!

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